METHOD FOR ACCELERATING GROWTH OF COFFEE PLANTS

Abstract

Title: METHOD FOR ACCELERATING GROWTH OF COFFEE PLANTS Abstract The invention disclosed herein relates to methods for growing coffee plants, in particular methods for growing a coffee plant under such conditions that within 160 days the plant has a total leaf area per plant of at least 725 cm2. The invention also relates to a coffee plant per se, coffee beans obtainable from said coffee plant, roasted coffee beans, roasted ground coffee and / or a coffee beverage prepared from said roasted ground coffee, an arrangement to carry out said methods, a plant cultivation facility comprising said arrangement, as well as a use of artificial light to accelerate the growth of a coffee plant.

Description

P137505NL00 Title: METHODFORACCELERATINGGROWTHOF COFFEEPLANTS TECHNOLOGICAL FIELD The invention disclosed herein relates to methods for growing coffee plants, coffee plantsper se, coffee beans from said coffee plants, roasted coffee beans and roasted ground coffee prepared from said coffee beans and coffee beverages prepared from said roasted ground coffee, arrangements to carry out said methods, plant cultivation facilities comprising said arrangement, and the use of articial light to accelerate growth ofcoffee plants. BACKGROUND Plants ofthe genus Coea, also called coffee plants, are cultivated in over 70 countries. The fruits from coffee plants, also known as coffee cherries, contain beans that are used in the production ofcoffee beverages. The process ofgrowing coffee fruits starting from seeds of coffee plants is lengthy. Typically, seed is sown in an outdoors nursery bed, and the resulting seedlings grow slowly until they are large enough to be transferred to the eld. When a coffee plant is ready to be transferred to the eld, it is typically referred to as a young plant. On average, it takes about 160-240 days from sowing to obtain ayoung plantwhen growing said plant outdoors. Such outdoor grown young plants only have about seven leafpairs with a total leafarea per plant ofwell below 700 cm2, and are only about 20-45 cm tall. Moreover, during the outdoors nursery stage the conditions are not well-controlled, as the weather conditions are not constant. Furthermore, there may be an undesired degree ofvariation between different plants, and / or the plants may be exposed to pests and diseases. As such, it is desired that methods are developed that accelerate the growth of coffee plants, in particular such thatyoung coffee plants can be transferred sooner to the eld, shortening the production cycle. In particular, it is desired that such a method be provided that can be readily carried out, allows employing controlled conditions (including controlled environmental conditions such as light, C02, relative humidity, and the like, pest control, and / or disease control), may reduce the variation between plants, and / or is economical. Some efforts have been made in this respect. For example, in background reference WO 2024 / 023117 it is attempted to accelerate the time to owering and / or increasing the number ofowers and / or fruits ofa plant oftheRubiaceae family (which includes the genus Coea) by pruning the plant once it has reached a stage wherein the plant comprises a fork from which an orthotropic shoot and at leasttwo plagiotropic branches have developed. However, this approachmay be rather labour-intensive, and in said reference growth acceleration may be only achieved once the plant has already reached a certain stage. Moreover, as shown in Figure 2 ofWO 2024 / 023117 even after more than 300 days no signicant difference was observed between a pruned plant and a control plant. As such, it is still desired to further accelerate the growth ofcoffee plants, to achieve said acceleration at an early stage, and / or to faster obtain signicant differences as compared to reference examples such as outdoor-grown coffee plants. Moreover, traditionally grown coffee plants produce coffee beans that are bitter, and contain high amounts of sugars, chlorogenic acids, and free amino acids that are commonly reduced by treating the coffee beans. Consequently, it is desired that coffee plants be produced ofwhich the coffee beans are less bitter, and / or contain lower amounts of sugars, chlorogenic acids, and / or free amino acids as compared to traditionally grown coffee. Said lower amounts may be advantageous, as a less demanding and / or shorter treatment ofthe coffee beans may be necessary to arrive at the desired amounts of sugars, chlorogenic acids, and / or free amino acids. SUMMARY The methods, arrangements, facilities, plants, coffee beans, roasted coffee beans, roasted ground coffee, coffee beverages, and uses as disclosed herein meet one or more of the abovementioned desires. In particular, one or more ofthe abovementioned desires are achieved by the method, arrangement, facility, plant, coffee bean, roasted coffee beans and roasted ground coffee, coffee beverage, and use as claimed. DETAILED DESCRIPTION In a general sense, the invention is based on thejudicious insight that providing articial light to a plant from the genus Coea in its early stages ofdevelopment, especially in the rst 160 days, preferably in the rst 130 days, more preferably in the rst 120 days, accelerates and / or improves the growth and development of said plant. In particular, methods as disclosed herein enable that ayoung plant is obtained more quickly, such thatyoung coffee plants can be transferred sooner to the eld, shortening the production cycle. This may be expressed in terms ofthe coffee plant having a total leaf area per plant of at least 725 cm2, preferably in a range offrom 725 to 4000 cm2, within 160 days, preferably within 130 days, more preferably within 120 days. Altematively or additionally, this may be expressed in terms ofthe coffee plant having within 160 days, preferably within 130 days, more preferably within 120 days: i) a total dry weight of at least 5.5 gram, preferably in a range offrom 6.0 to 50 gram, ii) an average internode length of at least 3.5 cm, preferably in a range offrom 4 to 17 cm, iii) an average leafarea per leafpair of at least 125 cm2, preferably in a range offrom 125 to 300 cm2, iv) a height of at least 35 cm, preferably in a range offrom 40 to 200 cm, v) a ratio ofthe dry weight ofthe shoot over the dry weight ofthe root of at least 110.6; preferably in a range offrom 1:06 to 1:005, and / or vi) a number ofleafpairs on the main stem of at least 6, preferably in a range offrom 6 to 18. It will be understood that the plant material used as a starting material in the method ofclaim 1, preferably does not yet have a total leafarea per plant of at least 725 cm2, and / or one or more of i)-vi) as dened in the previous sentence. The methods can be readily carried out, allow employing controlled conditions, may reduce the variation between plants, and / or are economical. In the methods ofthe invention plant material of a plant ofthe genus Coea is provided. It will be understood that herein, plant ofthe genus Coea and coffee plant are used interchangeably. In principle, any species ofthe genus Coea can be used in the methods ofthe invention, but it is preferred that the coffee plant is selected from the group consisting ofCoea arabica, Coea canephora, and Coea liberica, more preferably from the group consisting ofCoea arabica, and Coea canephora. In some embodiments, the coffee plant is ofthe species Coea ambica. In other embodiments, the coffee plant is of the species Coea canephora. It will be understood that the plant material is subjected to the method ofthe invention to obtain a (young) plant ofthe genus Coea. Especially, the term plant material may refer to any stage ofgrowth, at any moment starting from seed, seedling, cutting, or tissue culture plant, up to ayoung plant and even a mature plant. In principle, at any stage ofgrowth a coffee plant can benet from methods ofthe invention. Preferably, however, the plant material is selected from the group consisting of a seedling, a cutting, and a tissue culture plant. Preferably, the plant material is a seedling. Seedlings are readily obtained from seeds of a coffee plant. As used herein, seedling refers to a coffee plant at the developmental stage between germination and being ayoung plant. The seedling typically has a height of at most 39 cm, preferably at most 35 cm, more preferably at most 30 cm, more preferably at most 25 cm, more preferably at most 20 cm, more preferably at most 15 cm, more preferably at most 10 cm, and most preferably at most about 8 cm. Preferably, a seedling is used directly after germination. Preferably, the seedling is obtained by providing a seed and germinating said seed. As such, the method ofthe invention may also start with providing a seed of a coffee plant, and germinating said seed. Preferred methods ofgerminating said seed are mentioned below. The plant material may also be a cutting or a tissue culture plant. The advantage of using a cutting or a tissue culture plant is that substantial or even complete genetic homogeneity may be achieved between various coffee plants. The skilled person is aware how to obtain cuttings and / or tissue culture plants ofcoffee plants. The cutting or tissue culture plant typically has a height of at most 39 cm, preferably at most 35 cm, more preferably at most 30 cm, more preferably at most 25 cm, more preferably at most 20 cm, more preferably at most 15 cm, more preferably at most 10 cm, and most preferably at most about 8 cm. In the method ofthe invention, the plant material is exposed to light, wherein said light is substantially exclusively articial grow light. Articial grow light is non-natural light that induces the growth ofcoffee plants, in particular induces photosynthesis in coffee plants. Articial grow light has a different composition in terms ofwavelength and / or intensity than sunlight. An advantage ofusing articial grow light is that more control can be achieved, in the sense that a constant spectrum and intensity can be maintained throughout the day, whereas the composition and intensity of sunlight changes during the day. With substantially exclusively it is typically meant that at least 95%, preferably at least 97%, more preferably at least 98%, more preferably at least 99%, more preferably at least 99.9%, and most preferably 100%, ofthe light to which the coffee plant is exposed is articial grow light. Consequently, it is preferred that the plant material is not exposed to natural sunlight, and more preferably that the plant material is not exposed to any other light than said articial grow light. In particular, it is preferred that the plant material is shielded from natural sunlight, and more preferably that the plant material is shielded from any other light than said articial grow light. Preferably, the method ofthe invention is carried out indoors. As used herein, indoors typically refers to a substantially sunlight- free conditioned cultivation environment. This environment may also be congured to control the relative humidity ofthe air, the space temperature, the substrate temperature, and / or the carbon dioxide concentration ofthe air. Below, preferred features ofthe articial grow light are described. In particular, the photosynthetic ux density ofvarious components of said articial grow light are mentioned. Herein, the photosynthetic ux density is expressed in units of umol / mz / s. Therein, the area (m2) refers to the surface area at the top ofthe plant material, typically one or more leaves of said plant material. The skilled person will understand that to maintain a specic photosynthetic ux density or to remain within a range of photosynthetic ux densities throughout the method ofthe invention, the height ofthe one or more lighting devices that are typically used to produce the articial grow light and / or the height ofthe surface on which the plant material are kept, may be adjusted, if necessary, while the plant material grows. In other words: the distance between said lighting device and the plant material may be held substantially constantby for example increasing the height atwhich the lighting device is kept as the plant material grows and / or lowering the surface on which the plant material are kept, ifnecessary. Altematively, said distance may be xed for a certain room, and the plant material may be moved to a different room with a different xed distance between the lighting device and the plant material. For all ofthe articial grow light components listed herein it holds that no upper limit needs to be specied for the photosynthetic ux density, since exposing the plant material to more light is not detrimental to the growth ofthe plant. However, preferably an as low as possible photosynthetic ux density is used, so as to reduce costs, and / or provide a more environmentally friendly method. Preferably, the articial grow light comprises a red component having a wavelength in a range offrom 600 to 700 nm. Preferably, the red component comprises substantially all wavelengths within a range offrom 600 to 700 nm, with a peak between 650 and 670 nm, preferably at 660 nm, and wherein the light intensities at 600nm and 700 nm are less than 5%, preferably less than 2%, more preferably less than 1% ofthe intensity at said peak. Preferably, the red component has a photosynthetic ux density of at least 30 umol / mZ / s, more preferably at least 50 umol / mZ / s, more preferably at least 75 umol / mz / s, more preferably at least 100 umol / mz / s, more preferably at least 125 umol / mz / s, more preferably at least 150 umol / mZ / s, more preferably at least 175 umol / mZ / s, more preferably at least 190 umol / mZ / s, more preferably at least 200 umol / mZ / s, and most preferably at least 210 umol / mZ / s. Preferably, the red component has a photosynthetic ux density of at most 1000 umol / mz / s, more preferably at most 750 umol / mz / s, more preferably at most 600 umol / mz / s, more preferably at most 500 umol / mz / s, more preferably at most 450 umol / mz / s, more preferably at most 400 umol / mz / s, more preferably at most 350 umol / mz / s, more preferably at most 300 umol / mz / s, more preferably at most 250 umol / mZ / s, and most preferably at most 230 umol / mZ / s. Preferably, the red component has a photosynthetic ux density in a range offrom 30 to 1000 umol / mZ / s, more preferably in a range offrom 50 to 750 umol / mz / s, more preferably in a range offrom 75 to 600 umol / mZ / s, more preferably in a range offrom 100 to 500 umol / mZ / s, more preferably in a range offrom 125 to 450 umol / mZ / s, more preferably in a range offrom 150 to 400 umol / mz / s, more preferably in a range offrom 175 to 350 umol / mZ / s, more preferably in a range offrom 190 to 300 umol / mz / s, more preferably in a range offrom 200 to 250 umol / mz / s, and most preferably offrom 210 to 230 umol / mZ / s. Most preferably, the red component has a photosynthetic ux density ofabout 220 umol / mz / s. Preferably, the articial grow light comprises a blue component having a wavelength in a range offrom 400 to 500 nm, preferably in a range offrom 420 to 495 nm. Preferably, the blue component comprises substantially all wavelengths within a range of from 420 to 495 nm, with a peak between 440 and 460 nm, preferably at 450 nm, and wherein the light intensities at 420nm and 495 nm are less than 5%, preferably less than 2%, more preferably less than 1% ofthe intensity at said peak. More preferably, the blue component comprises substantially all wavelengths within a range offrom 400 to 500 nm, with a peak between 440 and 460 nm, preferably at 450 nm, and wherein the light intensities at 400nm and 500 nm are less than 5%, preferably less than 2%, more preferably less than 1% ofthe intensity at said peak. Preferably, the blue component has a photosynthetic ux density of at least 10 umol / mZ / s, more preferably at least 20 umol / mZ / s, more preferably at least 25 umol / mz / s, more preferably at least 30 umol / mz / s, more preferably at least 40 umol / mZ / s, more preferably at least 45 umol / mZ / s, more preferably at least 50 umol / mZ / s, more preferably at least 55 umol / mz / s, more preferably at least 60 umol / mz / s, and most preferably at least 65 umol / mz / s. Preferably, the blue component has a photosynthetic ux density of at most 250 umol / mz / s, more preferably at most 200 umol / mz / s, more preferably at most 150 umol / mZ / s, more preferably at most 125 umol / mz / s, more preferably at most 100 umol / mZ / s, more preferably at most 95 umol / mz / s, more preferably at most 90 umol / mz / s, more preferably at most 85 umol / mZ / s, more preferably at most 80 umol / mZ / s, and most preferably at most 75 umol / mZ / s. Preferably, the blue component has a photosynthetic ux density in a range offrom 10 to 250 umol / mz / s, more preferably offrom 20 to 200 umol / mz / s, more preferably of from 25 to 150 umol / mZ / s, more preferably offrom 30 to 125 umol / mz / s, more preferably offrom 40 to 100 umol / mZ / s, more preferably offrom 45 to 95 umol / mZ / s, more preferably offrom 50 to 90 umol / mZ / s, more preferably offrom 55 to 85 umol / mZ / s, more preferably offrom 60 to 80 umol / mZ / s, and most preferably offrom 65 to 75 umol / mZ / s. Most preferably, the blue component has a photosynthetic ux density ofabout 70 umol / mZ / s. Preferably, the articial grow light comprises a far-red component having a wavelength in a range offrom 680 to 800 nm, more preferably in a range offrom 680 to 770 nm, more preferably in a range offrom 701 to 770 nm. Preferably, the far-red component comprises substantially all wavelengths within a range offrom 701 to 770 nm, with a peak in a range offrom 720 to 750 nm, preferably in a range offrom730 to 740 nm, and wherein the light intensities at 701 nm is less than 30%, preferably less than 25%, and more preferably less than 23% ofthe intensity at said peak, and the light intensity at 770 nm is less than 5%, preferably less than 4%, more preferably less than 3% ofthe intensity at said peak. More preferably, the far-red component comprises substantially all wavelengths within a range offrom 680 to 770 nm, with a peak between 730 and 750 nm, preferably in a range offrom 730 to 740 nm, and wherein the light intensities at 680 nm and 770nm are less than 6%, preferably less than 5%, more preferably less than4% ofthe intensity at said peak. Preferably, the far-red component has a photosynthetic ux density of at least 1 umol / mZ / s, more preferably at least 2 umol / mZ / s, more preferably at least 5 umol / mz / s, more preferably at least 8 umol / mz / s, more preferably at least 10 umol / mz / s, more preferably at least 12 umol / mZ / s, more preferably at least 15 umol / mZ / s, more preferably at least 18 umol / mz / s, more preferably at least 20 umol / mz / s, and most preferably at least 25 umol / mz / s. Preferably, the far-red component has a photosynthetic ux density of at most 100 umol / mZ / s, more preferably at most 75 umol / mz / s, more preferably at most 60 umol / mz / s, more preferably at most 50 umol / mZ / s, more preferably at most 47 umol / mZ / s, more preferably at most 45 umol / mz / s, more preferably at most 42 umol / mz / s, more preferably at most 40 umol / mZ / s, more preferably at most 37 umol / mZ / s, and most preferably at most 35 umol / mZ / s. Preferably, the far-red component has a photosynthetic ux density in a range of from 1 to 100 umol / mZ / s, more preferably offrom 2 to 75 umol / mz / s, more preferably of from 5 to 60 umol / mZ / s, more preferably offrom 8 to 50 umol / mz / s, more preferably of from 10 to 47 umol / mZ / s, more preferably offrom 12 to 45 umol / mz / s, more preferably of from 15 to 42 umol / mZ / s, more preferably offrom 18 to 40 umol / mz / s, more preferably of from 20 to 37 umol / mZ / s, and most preferably offrom 25 to 35 umol / mZ / s. Most preferably, the far-red component has a photosynthetic ux density ofabout 30 umol / mZ / s. Preferably, the articial grow light comprises the red component and the blue component, more preferably the articial grow light essentially consists ofthe red component and the blue component. Ifplants with a larger intemode length and / or taller plants are desired, it is however desired that the articial grow light comprises the far-red component. As such, preferably the articial grow light comprises the red component, the blue component, and the far-red component. More preferably, the articial grow light essentially consists ofthe red component, the blue component, and the far-red component. Ifthe articial grow light comprises said red component and said far-red component, it is preferred that the ratio ofthe photosynthetic ux density of said red component over the photosynthetic ux density ofthe far-red component is in a range of from 1:1 to 6011. More preferably, said ratio is offrom 2:1 to 40: 1, more preferably of from 3:1 to 30: 1, more preferably offrom 411 to 20: 1, more preferably offrom 5:1 to 15: 1, more preferably offrom 5.5:1 to 12: 1, more preferably offrom 611 to 911; even more preferably offrom 711 to 8:1. Most preferably, said ratio is about 7311. For all ofthe articial grow light components listed herein it holds that while lighting devices can be used that produce a single wavelength within the dened range, the best results are obtained when using one or more lighting devices that produce a range of wavelengths. Typically, the peak intensity of such light sources is at or around a specic wavelength, and the light intensity gradually decreases towards the lower and upper wavelengths ofthe range provided, typically forming a bell curve or a skewed distribution around said specic wavelength. At the lower and upper wavelengths ofthe range provided, the light intensity is typically less than 5%, preferably less than 2%, more preferably less than 1% ofthe intensity at said specic wavelength. For example, for the red light component a light source can be used producing light with wavelengths in a range offrom 600-700 nm with a peak between 650 and 670 nm, preferably at 660 nm. Likewise, for the blue light component a lighting device can be used producing light with wavelengths in a range offrom 420-495 nm with a peak between 440 and 460 nm, preferably at 450 nm. Similarly, for light having a far-red component a light source can be used producing light with wavelengths in a range offrom 701-770 nm, preferably in a range offrom 680-770 nm, with a peak in a range offrom 720 to 750 nm, preferably in a range offrom 730 to 740 nm. Preferably, in the methods ofthe invention the plant material is exposed to the articial grow light for at least 8 hours per day, preferably for at least 9 hours a day, more preferably at least 10 hours per day, more preferably at least 11 hours a day, more preferably at least 12 hours a day, and most preferably at least 13 hours a day. Preferably, in the methods ofthe invention the plant material is exposed to the articial grow light for at most 24 hours per day, preferably for at most 23 hours a day, more preferably at most 22 hours per day, more preferably at most 21 hours a day, more preferably at most 20 hours a day, even more preferably at most 19 hours a day, more preferably at most 18 hours a day, more preferably at most 17 hours a day, more preferably at most 16 hours a day, and most preferably at most 15 hours a day. Preferably, in the methods ofthe invention the plant material is exposed to the articial grow light for a duration in a range offrom 8 to 24 hours a day, more preferably offrom 9 to 22 hours a day, more preferably offrom 10 to 20 hours a day, more preferably offrom 11 to 18 hours a day, more preferably offrom 12 to 16 hours a day, and most preferably offrom 13 to 15 hours a day. Most preferably, in the methods ofthe invention the plant material is exposed to the articial grow light for about 14 hours a day. It will be understood that the exposure ofthe plant material to the articial grow light may be continuous or discontinuous throughout the day. However, it is preferred that the plant material is continuously exposed to the articial grow light during the time periods mentioned herein. When the plant material is not exposed to articial grow light during the methods ofthe invention, it is preferred that the plant material is not exposed to any visible light, more preferably that said plant material is kept in the dark. In principle, the growth ofand / or owering in the coffee plantmay be accelerated furtherby other means than exposing said plant to articial growth light, such as by pruning at a fork from which an orthotropic shoot and at least one plagiotropic branch have developed by removing at least the orthotropic shoot and maintaining the at least one plagiotropic branch, contacting the plant material with growth hormones (in particular synthetic and / or articial growth hormones), and / or genetically enhancing the plant material. However, one advantage ofthe methods ofthe invention is that such means are not necessary, thus making the process easier, more economical, and / or more readily available. Thus, the methods ofthe invention preferably do not comprise pruning the plant material at a fork from which an orthotropic shoot and at least one plagiotropic branch have developed by removing at least the orthotropic shoot and maintaining the at least plagiotropic branch. Likewise, the methods ofthe invention preferably do not comprise the step ofbringing the plant material into contact with growth hormones, in particular articial and / or synthetic growth hormones. Moreover, the methods ofthe invention preferably do not comprise genetically enhancing the plant material. It will be understood, however, that the methods ofthe invention optionally comprise pruning plant material having at least one plagiotropic branch by removing said at least one plagiotropic branch. Ifthe plagiotropic branches are pruned, it is preferred that all plagiotropic branches ofthe plant are pruned. Pruning may be carried out within about 4 weeks, preferably within about 3 weeks, ofthe formation ofthe plagiotropic branch. Duration OZmethod In principle, any coffee plant can benet from the method ofthe invention for any length oftime, whether it be short or for the entire lifetime of said plant. On the one hand, the longer the method ofthe invention is applied, the stronger and healthier a coffee plant may become. Therefore, it is preferred that the method ofthe invention is carried out for at least one day, more preferably at least 2 days, more preferably at least 5 days, more preferably at least 10 days, more preferably at least 15 days, more preferably at least 20 days, more preferably at least 25 days, more preferably at least 30 days, more preferably at least 40 days, more preferably at least 50 days, more preferably at least 60 days, more preferably at least 70 days, more preferably at least 80 days, more preferably at least 90 days, more preferably at least 100 days, more preferably at least 110 days, and most preferably at least 120 days. On the other hand, however, itmay be more cost-effective and more friendly to the environment to apply the method ofthe invention not longer than necessary, and to transfer the young coffee plant obtained with the method ofthe invention to the eld as soon as possible. Therefore, it is preferred that the method ofthe invention is carried out for at most 300 days, more preferably at most 270 days, more preferably at most 240 days, more preferably at most 220 days, more preferably at most 200 days, more preferably at most 180 days, more preferably at most 170 days, more preferably at most 160 days, more preferably at most 150 days, more preferably at most 140 days, more preferably at most 130 days, more preferably at most 110 days, and most preferably at most 120 days. Most preferably, the method ofthe invention is carried out for about 120 days. This is sufcient time to grow ayoung plant from a seed of a coffee plant. These periods relate towhen the starting material is a seed of a coffee plant, and a seedling is obtained therefrom by germinating said seed. As such, said periods include about 30 days for germination. When starting with a seedling directly, orwhen starting with a cutting or a tissue culture plant, the same periods apply minus 30 days. Typically, during the method ofthe invention the root ofthe plant material will be kept in a substrate. The substrate may be soil or an aqueous solution, but it is preferred that the substrate is soil. However, it will be understood that during the method ofthe invention the plant material can be repotted ifnecessary, and thus the rootmay temporarily not be kept in a substrate. Likewise, horticultural substrates and horticultural nutrient solutions suitable for the growth ofcoffee plants are known to the skilled person. Other parameters In principle, the methods ofthe invention work well, and accelerate the growth of plants ofthe genus Coea. However, even better results are obtained ifone or more other parameters are within certain ranges as well. These parameters are selected from the group consisting of space temperature, substrate temperature, relative humidity, COz concentration, electric conductivity ofthe substrate, and thepH ofthe substrate. The preferred values ofthese parameters are detailed below. In the methods ofthe invention the best results are obtained iffor all ofthese parameters the preferred values are used. The temperature ofthe plant material can be measured and adjusted using standard techniques known to the skilled person. Preferably, the plant material is kept at a temperature of at least 15°C, more preferably at least 16°C, more preferably at least 18°C, more preferably at least 19°C; more preferably at least 20°C, more preferably at least 21°C, more preferably at least 22°C, more preferably at least 23°C, more preferably at least 24°C, more preferably at least 25°C, and most preferably of at least 26°C. Preferably, the plant material is kept at a temperature of at most 40°C, more preferably at most 37°C, more preferably at most 36°C, more preferably at most 35°C, more preferably at most 34°C, more preferably at most 33°C, more preferably at most 32°C, more preferably at most 31°C, more preferably at most 30°C, more preferably at most 29°C, and most preferably of at most 28°C. Preferably, the plant material is kept at a temperature in a range offrom 15 to 40 °C, more preferably in a range offrom 16 to 39 °C, more preferably in a range offrom 18 to 38 °C, more preferably in a range offrom 19 to 37 °C, more preferably in a range of from 20 to 36 °C, more preferably in a range offrom 21 to 35 °C, more preferably in a range offrom 22 to 34 °C, more preferably in a range offrom 23 to 33 °C, more preferably in a range offrom 24 to 32 °C, more preferably in a range offrom 25 to 31 °C, most preferably in a range offrom 26 to 30 °C. Most preferably, the plant material is kept at a temperature ofabout 27 °C. In the methods ofthe invention, it is also possible to separately control the space temperature (viz. the air temperature) and the substrate temperature. Thus, the temperature ofthe root ofthe plant material can be controlled by the substrate temperature, and the temperature ofthe shoot ofthe plant material can be controlled by the space temperature. Although some variation between the space temperature and the substrate temperature is allowed, it is preferred that the space temperature and the substrate temperature are substantially the same. Preferably, the root ofthe plant material is kept at a temperature of at least 15°C, more preferably at least 16°C, more preferably at least 18°C, more preferably at least 19°C, more preferably at least 20°C, more preferably at least 21°C, more preferably at least 22°C, more preferably at least 23°C, more preferably at least 24°C, more preferably at least 25°C, and most preferably of at least 26°C. Preferably, the root ofthe plant material is kept at a temperature of at most 40°C, more preferably at most 37°C, more preferably at most 36°C, more preferably at most 35°C, more preferably at most 34°C, more preferably at most 33°C, more preferably at most 32°C, more preferably at most 31°C, more preferably at most 30°C, more preferably at most 29°C, and most preferably of at most 28°C. Preferably, the root ofthe plant material is kept at a temperature in a range offrom 15 to 40 °C, more preferably in a range offrom 16 to 39 °C, more preferably in a range of from 18 to 38 °C, more preferably in a range offrom 19 to 37 °C, more preferably in a range offrom 20 to 36 °C, more preferably in a range offrom 21 to 35 °C, more preferably in a range offrom 22 to 34 °C, more preferably in a range offrom 23 to 33 °C, more preferably in a range offrom 24 to 32 °C, more preferably in a range offrom 25 to 31 °C, most preferably in a range offrom 26 to 30 °C. Most preferably, the root ofthe plant material is kept at a temperature ofabout 27 °C. Preferably, the shoot ofthe plant material is kept at a temperature of at least 15°C, more preferably at least 16°C, more preferably at least 18°C, more preferably at least 19°C, more preferably at least 20°C, more preferably at least 21°C, more preferably at least 22°C, more preferably at least 23°C, more preferably at least 24°C, more preferably at least 25°C, and most preferably of at least 26°C. Preferably, the shoot ofthe plant material is kept at a temperature of at most 40°C, more preferably at most 37°C, more preferably at most 36°C, more preferably at most 35°C, more preferably at most 34°C, more preferably at most 33°C, more preferably at most 32°C, more preferably at most 31°C, more preferably at most 30°C, more preferably at most 29°C, and most preferably of at most 28°C. Preferably, the shoot ofthe plant material is kept at a temperature in a range of from 15 to 40 °C, more preferably in a range offrom 16 to 38 °C, more preferably in a range offrom 17 to 37 °C, more preferably in a range offrom 18 to 36 °C, more preferably in a range offrom 19 to 35 °C, more preferably in a range offrom 20 to 34 °C, more preferably in a range offrom 21 to 33 °C, more preferably in a range offrom 22 to 32 °C, more preferably in a range offrom 23 to 29 °C, most preferably in a range offrom 24 to 28 °C. Most preferably, the shoot ofthe plant material is kept at a temperature ofabout 25 °C. The relative humidity of air can be measured and adjusted using standard techniques known to the skilled person. As used herein, relative humidity indicates a present state of absolute humidity relative to amaximum humidity given the same temperature. Therein, absolute humidity is the actual water content ofthe air, and is typically expressed as either mass ofwatervapor pervolume ofmoist air (in grams per cubic meter) or as mass ofwatervapor per mass ofdry air (usually in grams per kilogram) Preferably, the plant material is subjected to a relative humidity of at least 60%, more preferably of at least 62%, more preferably of at least 65%, more preferably of at least 70%, more preferably of at least 72%, more preferably of at least 75%, more preferably of at least 76%, more preferably of at least 77%, more preferably of at least 78%, and least preferably of at least 79%. Preferably, the plant material is subjected to a relative humidity of at most 100%, more preferably of at most 95%, more preferably of at most 90%, more preferably of at most 87%, more preferably of at most 86%, more preferably of at most 85%, more preferably of at most 84%, more preferably of at most 83%, more preferably of at most 82%, and most preferably of at most 81%. Preferably, the plant material is subjected to a relative humidity in a range offrom 60 to 100%, more preferably in a range offrom 62 to 95%, more preferably in a range of from 65 to 90%, more preferably in a range offrom 70 to 87%, more preferably in a range offrom 72 to 86%, more preferably in a range offrom 75 to 85%, more preferably in a range offrom 76 to 84%, more preferably in a range offrom 77 to 83%, more preferably in a range offrom 78 to 82%, and most preferably offrom preferably in a range offrom 79 to 81%. Most preferably, the plant material is subjected to a relative humidity ofabout 80%. The C02 concentration in air can be measured and adjusted using standard techniques known to the skilled person. Preferably, the plant material is subjected to air having a C02 concentration of at least 250 ppm, more preferably at least 400 ppm, more preferably at least 450 ppm, more preferably at least 500 ppm, more preferably at least 600 ppm, more preferably at least 700 ppm, more preferably at least 800 ppm, more preferably at least 900 ppm, more preferably at least 1000 ppm, more preferably at least 1100 ppm, more preferably at least 1200 ppm, more preferably at least 1300 ppm, and most preferably at least 1400 ppm. Preferably, the plant material is subjected to air having a C02 concentration of at most 2750 ppm, more preferably at most 2600 ppm, more preferably at most ppm, more preferably at most 2500 ppm, more preferably at most 2400 ppm, more preferably at most 2300 ppm, more preferably at most 2200 ppm, more preferably at most 2100 ppm, more preferably at most 2000 ppm, more preferably at most 1900 ppm, more preferably at most 1800 ppm, more preferably at most 1700 ppm, and most preferably at most 1600 ppm. Preferably, the plant material is subjected to air having a C02 concentration in a range offrom 250 to 2750 ppm, more preferably in a range offrom 400 to 2600 ppm, more preferably in a range offrom 500 to 2500 ppm, more preferably in a range offrom 600 to 2400 ppm, more preferably in a range offrom 700 to 2300 ppm, more preferably in a range offrom 800 to 2200 ppm, more preferably in a range offrom 900 to 2100 ppm, more preferably in a range offrom 1000 to 2000 ppm, more preferably in a range offrom 1100 to 1900 ppm, more preferably in a range offrom 1200 to 1800 ppm, more preferably in a range offrom 1300 to 1700 ppm, and most preferably in a range offrom 1400 to 1600 ppm. Most preferably, the plant material is subjected to air having a C02 concentration of about 1500 ppm. The electrical conductivity ofthe substrate can be measured and adjusted using standard techniques known to the skilled person. Preferably, the electrical conductivity ofthe substrate in which the plant material of the coffee plants grows is maintained at a value of at least 1.0 mS / cmz, more preferably at least 1.2 mS / cmz, more preferably at least 1.3 mS / cmz, more preferably at least 1.4 mS / cmz, more preferably at least 1.5 mS / cmz, more preferably at least 1.6 mS / cmz, more preferably at least 1.7 mS / cmz, more preferably at least 1.8 mS / cmz, and most preferably at least 1.9 mS / cmz. Preferably, the electrical conductivity ofthe substrate in which the plant material of the coffee plants grows is maintained at a value of at most 3.0 mS / cmz, more preferably at most 2.9 mS / cmz, more preferably at most 2.8 mS / cmz, more preferably at most 2.7 mS / cmz, more preferably at most 2.6 mS / cmz, more preferably at most 2.5 mS / cmz, more preferably at most 2.4 mS / cmz, more preferably at most 2.3 mS / cmz, more preferably at most 2.2 mS / cmz, and most preferably at most 2.1 mS / cmz. Preferably, the electrical conductivity ofthe substrate in which the plant material of the coffee plants grows is maintained in a range offrom 1.0 to 3.0 mS / cmz, more preferably offrom 1.1 to 2.9 mS / cmz, more preferably offrom 1.2 to 2.8 mS / cmz, more preferably offrom 1.3 to 2.7 mS / cmz, more preferably offrom 1.4 to 2.6 mS / cmz, more preferably offrom 1.5 to 2.5 mS / cmz, more preferably offrom 1.6 to 2.4 mS / cmz, more preferably offrom 1.7 to 2.3 mS / cmz, more preferably offrom 1.8 to 2.2 mS / cmz, and most preferably in a range offrom 1.9 to 2.1 mS / cmz. Most preferably, the electrical conductivity ofthe substrate in which the plant material ofthe coffee plants grows is maintained at a value ofabout 2.0 mS / cmz. ThepH ofthe soil can be measured and adjusted using standard techniques known to the skilled person. Preferably, the pH ofthe substrate in which the plant material ofthe coffee plants grows is maintained at a value of at least 4.5, more preferably at least 4.8, more preferably at least 5.0, even more preferably at least 5.2, more preferably at least 5.4, more preferably at least 5.6, and most preferably at least 5.8. Preferably, the pH ofthe substrate in which the plant material ofthe coffee plants grows is maintained at a value of at most 7.0, more preferably at most 6.8, more preferably at most 6.7, even more preferably at most 6.6, more preferably at most 6.5, more preferably at most 6.4, more preferably at most 6.3, more preferably at most 6.2, more preferably at most 6.1, and most preferably at most 6.0. Preferably, the pH ofthe substrate in which the plant material ofthe coffee plants grows is maintained in a range offrom 4.5 to 7.0, more preferably offrom 4.7 to 6.9, more preferably offrom 4.9 to 6.7, more preferably offrom 5.1 to 6.5, more preferably offrom 5.2 to 6.3, more preferably offrom 5.4 to 6.2, more preferably offrom 5.6 to 6.1, and most preferably offrom 5.8 to 6.0. Most preferably, the pH ofthe substrate in which the plant material ofthe coffee plants grows is maintained at about 5.9. When multiple coffee plants are grown simultaneously using a method ofthe invention, it is preferred that the leafarea index is at most 4, more preferably at most 3.5. In this way, the plant material can be optimally exposed to the articial grow light. As used herein, leaf area index refers to the total leaf area present within a certain area divided by the ground surface area of said area. Herein, the leaf area is the amount of surface area of leaves ofplants (eg. one plant may have 1000 cm2 ofleafarea divided over 8 leaves). Ifin a method ofthe invention the starting material is a seedling, then for the rst about 20-90 days carrying out said method, not including time for germination, it is preferred that the seedling is kept in a container, such as a pot or a plug, preferably a plug, having avolume in a range offrom 50 to 150 mL, preferably offrom 65 to 130 mL, more preferably offrom 90 to 100 mL, and most preferably about 95 mL. In that case, it is preferred that on a day in the range offrom day 20 to day 90 ofcarrying out said method, not including time for germination, the plant material is transferred to a container, such as a pot or a plug, preferably a plug, having avolume in a range offrom 200 to 2000 mL, preferably offrom 300 to 1000 mL, more preferably offrom 500 to 900 mL, and most preferably ofabout 750 mL. Altematively, it is preferred that on a day in the range offrom day 20 to day 90 ofcarrying out said method, not including time for germination, the plant material is transferred to a container such as a pot or a plug, preferably a plug, having a volume in a range offrom 200 to 3000 mL, preferably offrom 300 to 2000 mL, more preferably offrom 500 to 1500 mL, more preferably offrom 750 to 1250 mL, and most preferably ofabout 1000 mL. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then the same values apply as indicated above in relation to a seedling. Firstdays 01a cutting or tissue culture plant Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then in the rst 8 days, and most preferably the rst 7 days it is preferred that the below values are used for the temperature, the relative humidity, and / or the articial grow light. After said rst days, it is preferred that the conditions as listed above are applied. If in a method ofthe invention the starting material is a seedling, it is preferred that the conditions as listed above are applied throughout conducting said method. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then in the rst about 3 days, the articial grow light preferably comprises a red component as dened herein. Then, the red component preferably has a photosynthetic ux density of at least 30 umol / mz / s, more preferably at least 40 umol / mz / s, more preferably at least 50 umol / mz / s, more preferably at least 60 umol / mZ / s, more preferably at least 70 umol / mZ / s, more preferably at least 80 umol / mZ / s, more preferably at least 90 umol / mZ / s, and most preferably at least 100 umol / mZ / s. Then, the red component preferably has a photosynthetic ux density of at most 190 umol / mz / s, more preferably at most 180 umol / mz / s, more preferably at most 170 umol / mZ / s, more preferably at most 160 umol / mZ / s, more preferably at most 150 umol / mz / s, more preferably at most 140 umol / mZ / s, more preferably at most 130 umol / mz / s, and most preferably at most 120 umol / mz / s. Then, preferably the red component has a photosynthetic ux density in a range offrom 30 to 190 umol / mZ / s, more preferably offrom 40 to 180 umol / mZ / s, more preferably offrom 50 to 170 umol / mZ / s, more preferably offrom 60 to 160 umol / mZ / s, more preferably offrom 70 to 150 umol / mZ / s, more preferably offrom 80 to 140 umol / mZ / s, more preferably offrom 90 to 130 umol / mZ / s, and most preferably offrom 100 to 120 umol / mz / s. Then, most preferably the red component has a photosynthetic ux density ofabout 110 umol / mZ / s. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then on days 4 to 7 ofcarrying out said method, the articial grow light preferably comprises a red component as dened herein. Then, the red component preferably has a photosynthetic ux density of at least 75 umol / mz / s, more preferably at least 85 umol / mZ / s, more preferably at least 100 umol / mz / s, more preferably at least 110 umol / mZ / s, more preferably at least 120 umol / mz / s, more preferably at least 130 umol / mZ / s, more preferably at least 140 umol / mz / s, and most preferably at least 150 umol / mz / s. Then, the red component preferably has a photosynthetic ux density of at most 300 umol / mZ / s, more preferably at most 260 umol / mZ / s, more preferably at most 240 umol / mz / s, more preferably at most 220 umol / mz / s, more preferably at most 200 umol / mZ / s, more preferably at most 180 umol / mz / s, more preferably at most 170 umol / mz / s, and most preferably at most 160 umol / mz / s. Then, preferably the red component has a photosynthetic ux density in a range offrom 75 to 300 umol / mZ / s, more preferably offrom 85 to 260 umol / mZ / s, more preferably offrom 100 to 240 umol / mZ / s, more preferably offrom 110 to 220 umol / mz / s, more preferably offrom 120 to 200 umol / mZ / s, more preferably offrom 130 to 180 umol / mZ / s, more preferably offrom 140 to 170 umol / mZ / s, and most preferably offrom 150 to 160 umol / mZ / s. Then, most preferably the red component has a photosynthetic ux density ofabout 155 umol / mz / s. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then in the rst about 3 days, the articial grow light preferably comprises a blue component as dened herein. Then, the blue component preferably has a photosynthetic ux density of at least 5 umol / mz / s, more preferably at least 10 umol / mz / s, more preferably at least 15 umol / mz / s, more preferably at least 20 umol / mZ / s, more preferably at least 25 umol / mZ / s, and most preferably at least 30 umol / mZ / s. Then, the blue component preferably has a photosynthetic ux density of at most 100 umol / mz / s, more preferably at most 80 umol / mz / s, more preferably at most 70 umol / mZ / s, more preferably at most 60 umol / mZ / s, more preferably at most 50 umol / mz / s, and most preferably at most 40 umol / mz / s. Then, preferably the blue component has a photosynthetic ux density in a range offrom 5 to 100 umol / mZ / s, more preferably offrom 10 to 80 umol / mZ / s, more preferably offrom 15 to 70 umol / mZ / s, more preferably offrom 20 to 60 umol / mZ / s, more preferably offrom 25 to 50 umol / mZ / s, and most preferably offrom 30 to 40 umol / mZ / s. Then, most preferably the blue component has a photosynthetic ux density ofabout 35 umol / mz / s. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then on days 4 to 7 ofcarrying out said method, the articial grow light preferably comprises a blue component as dened herein. Then, the blue component preferably has a photosynthetic ux density of at least 20 umol / mz / s, more preferably at least 25 umol / mZ / s, more preferably at least 30 umol / mz / s, more preferably at least 35 umol / mZ / s, more preferably at least 40 umol / mZ / s, and most preferably at least 45 umol / mZ / s. Then, the blue component preferably has a photosynthetic ux density of at most 100 umol / mz / s, more preferably at most 80 umol / mZ / s, more preferably at most 75 umol / mZ / s, more preferably at most 70 umol / mz / s, more preferably at most 65 umol / mZ / s, and most preferably at most 60 umol / mz / s. Then, preferably the blue component has a photosynthetic ux density in a range offrom 20 to 100 umol / mz / s, more preferably of from 25 to 80 umol / mZ / s, more preferably offrom 30 to 75 umol / mZ / s, more preferably of from 35 to 70 umol / mZ / s, more preferably offrom 40 to 65 umol / mZ / s, and most preferably offrom 45 to 60 umol / mz / s. Then, most preferably the blue component has a photosynthetic ux density ofabout 50 umol / mz / s. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then during the rst about 3 days, the articial grow light preferably comprises a far- red component as dened herein. Then, the far-red component preferably has a photosynthetic ux density of at least 1 umol / mz / s, more preferably at least 3 umol / mz / s, more preferably at least 5 umol / mz / s, more preferably at least 7 umol / mz / s, more preferably at least 10 umol / mZ / s, and most preferably at least 12 umol / mZ / s. Then, the far- red component preferably has a photosynthetic ux density of at most 30 umol / mz / s, more preferably at most 25 umol / mz / s, more preferably at most 22 umol / mz / s, more preferably at most 20 umol / mZ / s, more preferably at most 19 umol / mZ / s, and most preferably at most 17 umol / mz / s. Then, preferably the far-red component has a photosynthetic ux density in a range offrom 1 to 30 umol / mZ / s, more preferably offrom 3 to 25 umol / mZ / s, more preferably offrom 5 to 22 umol / mZ / s, more preferably offrom 7 to 20 umol / mZ / s, more preferably offrom 10 to 19 umol / mZ / s, and most preferably offrom 12 to 17 umol / mZ / s. Then, most preferably the far-red component has a photosynthetic ux density ofabout 15 umol / mZ / s. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then on days 4 to 7 ofcarrying out said method, the articial grow light preferably comprises a far-red component as dened herein. Then, the far-red component preferably has a photosynthetic ux density of at least 11 umol / mZ / s, more preferably at least 14 umol / mZ / s, more preferably at least 16 umol / mZ / s, more preferably at least 17 umol / mz / s, and most preferably at least 19 umol / mz / s. Then, the far-red component preferably has a photosynthetic ux density of at most 41 umol / mz / s, more preferably at most 36 umol / mZ / s, more preferably at most 31 umol / mZ / s, more preferably at most 26 umol / mZ / s, and most preferably at most 23 umol / mZ / s. Then, preferably the far-red component has a photosynthetic ux density in a range offrom 11 to 41 umol / mz / s, more preferably offrom 14 to 36 umol / mz / s, more preferably offrom 16 to 31 umol / mz / s, more preferably offrom 17 to 26 umol / mZ / s, and most preferably offrom 19 to 23 umol / mZ / s. Then, most preferably the far-red component has a photosynthetic ux density ofabout 21 umol / mZ / s. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then in the rst about 3 days, the relative humidity ofthe air is preferably at least 75%, more preferably at least 80%, more preferably at least 85%, and most preferably at least 88%. Then, the relative humidity ofthe air is preferably at most 99%, more preferably at most 97%, more preferably at most 95%, and most preferably at most 92%. Then, the relative humidity ofthe air is preferably ofin a range from 75 to 99%, more preferably of from 80 to 97%, more preferably offrom 85 to 95%, and most preferably offrom 88 to 92%. Then, most preferably the relative humidity ofthe air is about 90%. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then on days 4 to 7 ofcarrying out said method, the relative humidity ofthe air is preferably at least 75%, more preferably at least 78%, more preferably at least 81% and most preferably at least 83%. Then, the relative humidity ofthe air is preferably at most 95%, more preferably at most 92% more preferably at most 89%, and most preferably at most 87%. Then, the relative humidity ofthe air is preferably ofin a range from 75 to 95%, more preferably offrom 78 to 92%, more preferably offrom 81 to 89%, and most preferably offrom 83 to 87%. Then, most preferably the relative humidity ofthe air is about 85%. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then during the rst about 1 day ofcarrying out said method, it is preferred that the cutting or the tissue culture plant is kept at a temperature of at least 17°C, more preferably at least 18°C, and most preferably at least 19°C. Then, preferably the cutting or the tissue culture plant is kept at a temperature of at most 23°C, more preferably at most 22°C, and most preferably at most 21°C. Then, preferably the cutting or the tissue culture plant is kept at a temperature in a range offrom 17 to 23°C, more preferably offrom 18 to 22°C, and most preferably offrom 19 to 21°C. Then, most preferably the cutting or the tissue culture plant is kept at a temperature ofabout 20°C. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then on days 2 to 3 ofcarrying out said method, it is preferred that the cutting or the tissue culture plant is kept at a temperature of at least 19°C, more preferably at least 20°C, and most preferably at least 21°C. Then, preferably the cutting or the tissue culture plant is kept at a temperature of at most 25°C, more preferably at most 24°C, and most preferably at most 23°C. Then, preferably the cutting or the tissue culture plant is kept at a temperature in a range offrom 19 to 25°C, more preferably offrom 20 to 24°C, and most preferably offrom 21 to 23°C. Then, most preferably the cutting or the tissue culture plant is kept at a temperature ofabout 22°C. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then on days 4 to 7 ofcarrying out said method, it is preferred that the cutting or the tissue culture plant is kept at a temperature of at least 22°C, more preferably at least 23°C, and most preferably at least 24°C. Then, preferably the cutting or the tissue culture plant is kept at a temperature of at most 28°C, more preferably at most 27°C, and most preferably at most 26°C. Then, preferably the cutting or the tissue culture plant is kept at a temperature in a range offrom 22 to 28°C, more preferably offrom 23 to 27°C, and most preferably offrom 24 to 26°C. Then, most preferably the cutting or the tissue culture plant is kept at a temperature ofabout 25°C. Ifin a method ofthe invention the starting material is a cutting or a tissue culture plant, then for the rst about 7 days ofcarrying out said method, it is preferred that the substrate temperature and the space temperature are substantially the same. Germination method Herein, preferred methods for germinating a seed of a coffee plant are described. The steps ofthese methods may precede the steps ofthe method ofthe invention, ifthe starting material in the lattermethod is a seed. However, the methods for germinating a seed of a coffee plant as described herein can also be carried out separately (i. e. without having to be followed by the steps ofthe method ofthe invention) and are in themselves also highly advantageous. In particular, the germination methods described herein may achieve fast germination. Thus, the invention also pertains to a method for germinating a seed ofa coffee plant so as to obtain a seedling, wherein the method comprises the steps of: (a) providing a seed of a coffee plant, (b) covering said seed with soil, preferably burying said seed in soil, wherein said soil is in contact with air, and (c) applying one or more ofthe following conditions for at least 20 days, more preferably at least 25 days, more preferably at least 27 days, and most preferably for about 30 days: (i) maintaining the soil temperature in a range offrom 25 to 35 °C, preferably in a range offrom 27 to 33 °C, more preferably in a range offrom 29 to 31 °C, and most preferably at about 30 °C, (ii) maintaining the relative humidity ofthe air in a range offrom 85 to 95%, preferably in a range offrom 87 to 92%, and most preferably at about 90%, (iii) maintaining the C02 concentration in the air in a range offrom 300 to 700 ppm, preferably offrom 320 to 650 ppm, more preferably offrom 350 to 550 ppm, more preferably offrom 370 to 470 ppm, more preferably offrom 400 to 440 ppm, and most preferably at about 420 ppm. In some embodiments, in step (c) ofthe method for germinating a seed of a coffee plant conditions (i) and (ii) are applied. In some embodiments, in step (c) ofthe method for germinating a seed ofa coffee plant conditions (i) and (iii) are applied. In some embodiments, in step (c) ofthe method for germinating a seed of a coffee plant conditions (ii) and (iii) are applied. Preferably, in step (c) ofthe method for germinating a seed ofa coffee plant conditions (i), (ii), and (iii) are applied. Preferably, in the germination method the seed is not exposed to articial grow light. More preferably, in the germination method the seed is kept in the dark. Preferably, in the germination method the seed is sowed in a container such as a pot or a plug, preferably a plug, having avolume in a range offrom 50 to 100 mL, preferably offrom 65 to 90 mL, more preferably offrom 70 to 80 mL, and most preferably about 75 mL. % The invention also relates to a plant ofthe genus Coea. Preferably, the plant is obtainable by a method as disclosed herein. Preferably, the plant has one or more ofthe following characteristics: a) a total leafarea per plant of at least 725 cm2, preferably in a range of from 900 to 4000 cm2, b) a total dry weight of at least 5.5 gram, preferably in a range of from 6.0 to 50 gram, c) an average internode length of at least 3.5 cm, preferably in a range offrom 4 to 17 cm, d) an average leafarea per leafpair of at least 125 cm2, preferably in a range offrom 125 to 300 cm2, e) a height of at least 35 cm, more preferably at least 50 cm, more preferably still at least 80 cm, preferably in a range offrom 40 to 200 cm, f) a ratio of the dry weight ofthe shoot over the dry weight ofthe root of at least 110.6; preferably in a range offrom 1:0.6 to 110.05, and / or g) a number ofleafpairs on the main stem of at least 6, preferably in a range offrom 6 to 18, wherein ifthe plant has a height offrom 40 to 45 cm it also has one or more of characteristics a)-d), f), and g), more preferably, the plant has at least characteristics a) and b), more preferably the plant has at least characteristics a), b), and g), more preferably the plant has at least characteristics a), b), e), and g), more preferably the plant has at least characteristics a), b), e), f), and g), more preferably at least characteristics a), b), d), e), f), and g), and most preferably the plant has at least characteristics a)-g). Herein, dry weight refers to the weight of a plant or a part thereof after said plant or part thereofhas been dried. Usually, the residual moisture level in said plant or part thereof after drying is at most 10 wt%, preferably at most 5 wt%, as compared to the total weight ofthe dried plant or dried part. Plant characteristics a)-g) and further preferred values thereof are further discussed below. Preferably, the plant has a total leafarea of at least 725 cm2, more preferably at least 900 cm2, more preferably at least 1000 cm2, more preferably at least 1100 cm2, more preferably at least 1150 cm2, more preferably at least 1200 cm2, and most preferably at least 1225 cm2. Preferably, the plant has a total leafarea of at most 4000 cm2, more preferably at most 3500 cm2, more preferably at most 3000 cm2, more preferably at most 2750 cm2, more preferably at most 2600 cm2, and most preferably at most 2550 cm2. Preferably, the plant has a total leafarea in a range offrom 900 to 4000 cm2, more preferably offrom 1000 to 3500 cm2, more preferably offrom 1100 to 3000 cm2, more preferably offrom 1150 to 2750 cm2, more preferably offrom 1150 to 2600 cm2, and most preferably offrom 1200 to 2550 cm2. Preferably, the plant has a total leafarea ofabout 1225 cm2,about 1750 cm2, or about 2500 cm2. The area of a leafcan be measured manually, for example by using millimeter graph paper, or by other means. For instance, a photograph can be taken ofone or more leaves on a contrasting background with aknown scale object. Software such as Image] can then be used to apply a scale using the known object, locate the contour(s) ofthe one or more leaves, and measure the leaf area. Furthermore, the leafarea can be determined automatically using handheld or portable leafarea meters that measure leafareaby scanning the surface ofthe leaf. This is a non-destructive method that the skilled person can readily use, also to measure the total leafarea of a plant. Alternatively, a destructive method can also be employed if desired. In that case, all leaves of a plantmay be harvested and dried, and the total weight ofthe dried leaves may be determined. The total leafarea can then be obtained from multiplying the total dry weight with a certain conversion factor. This conversion factor can be obtained from literature, and / or by measuring the dry weight of a sample ofleaves with aknown area. An alternative to drying and weighing the leaves is to scan the leaves and analyze their surface area digitally. For determining the total leafarea per plant of a large number of plants, only a small number ofplants (e.g. at most 5% of all plants, or about 10 plants) may need to be examined. The average ofthe results obtained in this way can be considered to be representative for all plants. This is in particular useful when employing the destructive method, as itmay not be necessary to harvest the leaves of all plants. Preferably, the plant has a total dry weight of at least 5.5 gram, more preferably at least 6.0 gram, more preferably at least 6.5 gram, more preferably at least 7.0 gram; more preferably at least 10 gram, more preferably at least 15 gram, and most preferably at least 17 gram. Preferably, the plant has a total dry weight of at most 50 gram, more preferably at most 45 gram, more preferably at most 40 gram, more preferably at most 35 gram, more preferably at most 30 gram, and most preferably at most 25 gram. Preferably, the plant has a total dry weight in a range offrom 6.0 to 50 gram, more preferably offrom 6.5 to 45 gram; more preferably offrom 7.0 to 40 gram; more preferably offrom 10 to 35 gram, more preferably offrom 15 to 30 gram, and most preferably offrom 17 to 25 gram. Preferably, the plant has a total dry weight ofabout 20 gram. In other embodiments, however, the plant has a total dry weight ofabout 8.0 gram. Herein, the dry weight ofthe entire plant (viz. both shoot and root) is meant. Preferably, the plant has an average internode length of at least 3.5 cm, more preferably at least 4.0 cm, more preferably at least 4.5 cm, more preferably at least 5.0 cm, more preferably at least 5.5 cm, and most preferably at least 6.0 cm. Preferably, the plant has an average internode length of at most 17 cm, more preferably at most 15 cm, more preferably at most 14 cm, more preferably at most 13 cm, more preferably at most 12 cm, and most preferably at most 11 cm. Preferably, the plant has an average internode length in a range offrom 3.5 to 17 cm, more preferably offrom 4.0 to 15 cm, more preferably offrom 4.5 to 14 cm, more preferably offrom 5.0 to 13 cm, more preferably offrom 5.5 to 12 cm, and most preferably offrom 6.0 to 11 cm. Preferably, the plant has an average internode length ofabout 6.4 cm, or about 10 cm. Typically, the plant comprises a stem having a leaf pair, preferably multiple leaf pairs. The leafpair is herein dened as two leaves on opposite sides ofthe stem. For determining the leafarea per leaf pair, the rst two leaves as well as the latest visual leaf pair are typically excluded from the measurement. Preferably, the plant has an average leaf area per leafpair of at least 75 cm2, more preferably at least 100 cm2, more preferably at least 120 cm2, more preferably at least 130 cm2, more preferably at least 140 cm2, and most preferably at least 150 cm2. Preferably, the plant has an average leaf area per leafpair of at most 300 cm2, more preferably at most 275 cm2, more preferably at most 250 cm2, more preferably at most 230 cm2, more preferably at most 220 cm2, and most preferably at most 200 cm2. Preferably, the plant has an average leaf area per leafpair in a range offrom 75 to 300 cm2, more preferably offrom 100 to 275 cm2, more preferably offrom 120 to 250 cm2, more preferably offrom 130 to 230 cm2, more preferably offrom 140 to 220 cm2, and most preferably offrom 150 to 200 cm2. Preferably, the plant has an average leaf area per leafpair ofabout 175 cm2. Preferably, the plant has a height of at least 20 cm, more preferably at least 25 cm, more preferably at least 30 cm, more preferably at least 35 cm, more preferably at least 40 cm, and most preferably at least 45 cm. Preferably, the plant has a height of at most 200 cm, more preferably at most 175 cm, more preferably at most 150 cm, more preferably at most 130 cm, more preferably at most 125 cm, and most preferably at most 120 cm. Preferably, the plant has a height in a range offrom 20 to 200 cm, more preferably offrom 25 to 175 cm, more preferably offrom 30 to 150 cm, more preferably offrom 35 to 130 cm, more preferably offrom 40 to 125 cm, and most preferably offrom 45 to 120 cm. Preferably, the plant has a height ofabout 45 cm, about 65 cm, about 100 cm, or about 120 cm. Preferably, the plant has a ratio ofthe dry weight ofthe shoot over the dry weight ofthe root of at least 110.6, more preferably at least 1:0.5, more preferably at least 1:0.4, and most preferably at least 1:0.35. Preferably, the plant has a ratio ofthe dry weight ofthe shoot over the dry weight ofthe root of at most 110.05, more preferably at most 110.1, more preferably at most 110.2, and most preferably at most 1:0.25. Preferably, the plant has a ratio ofthe dry weight ofthe shoot over the dry weight ofthe root in a range offrom 1:0.6 to 1:0.05, more preferably offrom 1:0.5 to 110.1, more preferably offrom 1:0.4 to 1:0.2, and most preferably offrom 1:0.35 to 1:0.25. Most preferably, the plant has a ratio ofthe dry weight ofthe shoot over the dry weight ofthe root ofabout 1:0.3. Herein, shoot refers to the part ofthe plant that is above ground, including the stem, leaves, fruit, and the like. By contrast, root refers to the part ofthe plant that is below ground. Said ratio can be determined by harvesting said plant, drying said plant, separating the shoot from the root, and measuring the dry weight ofthe shoot and the root, and comparing the dry weights. Alternatively, the shoot and the root are rst separated, and then dried separately. Preferably, the plant has a number ofleafpairs on the main stem of at least 6, more preferably at least 7, more preferably at least 8, and most preferably at least 9. Preferably, the plant has a number ofleafpairs on the main stem of at most 18, more preferably at most 16, more preferably at most 15, and most preferably at most 14. Preferably, the plant has a number ofleafpairs on the main stem in a range offrom 6 to 18, more preferably offrom 7 to 16, more preferably offrom 8 to 15, and most preferably offrom 9 to 14. Most preferably, the plant has a number ofleafpairs on the main stem ofabout 10 or about 14. In other embodiments, the plant has a number ofleafpairs on the main stem of about 7. Preferably, the plant ofthe genus Coea is selected from the group consisting of Coea arabica, Coea canephora, and Coea liberica, more preferably from the group consisting ofCoea arabica, and Coea canephora. In some embodiments, the plant of the genus Coea is ofthe species Coea arabica. In some embodiments, the plant ofthe genus Coea is ofthe species Coea canephora. Coffee beans The invention also relates to coffee beans obtainable from a plant ofthe genus Coea that is obtainable by a method for growing a plant ofthe genus Coea wherein the method comprises the steps ofproviding a plant ofthe genus Coea, and exposing said plant to light, wherein said light is substantially exclusively articial grow light. Preferably, the method is as disclosed in the claims. Moreover, the invention also relates to coffee beansper se. Advantageously and surprisingly, coffee beans according to the invention have higher total amounts oforganic acids and / or glucose, and lower total amounts of sugar, amino acids, and / or chlorogenic acids, as compared to traditionally grown coffee. In particular, coffee beans ofthe invention typically contain lower amounts of3-CQA, 4- CQA, 4-FQA, 5-CQA, and / or 5-FQA, as compared to traditionally grown coffee, wherein CQA denotes caffeoquuinic acid, andFQA indicates feruloquuinic acid. Moreover, coffee beans ofthe invention typically contain lower amounts offree amino acids selected from the group consisting of alanine, asparagine, proline, serine, tryptophan, and 7- aminobutyric acid, as compared to traditionally grown coffee. Standard methods to determine the amounts ofthese substances are known to the skilled person. As a result, coffee beans ofthe invention are advantageously less bitter than beans from traditionally grown coffee plants, and / or have an improved acidity. Below, preferred embodiments ofcoffee beans ofthe invention are discussed. The dry weight refers to weights and weight percentages as compared to the weight ofthe coffee bean excluding moisture. Unless indicated otherwise, the weight percentages and the weights used herein to describe the contents ofthe coffee beans ofthe invention relate to the dry weight. Therein, the wet weight refers to weights and weight percentages as compared to the weight ofthe coffee bean including moisture. The wet weight values presented below are based on coffee beans having a moisture content of 14.8 wt%. The weight offree amino acids and sugars refers to the amount ofamino acids and sugars that are covalently linked to further amino acids or sugars, respectively. For example, for amino acids this means that a free amino acid is not part of a peptide or protein. The total weight or total amount ofamino acids and monosaccharides refers to the amount ofamino acids and monosaccharides obtained after complete hydrolysis ofthe contents ofthe coffee bean ofthe invention. This means that all peptides, proteins, oligo- and polysaccharides are degraded to their constitutional parts, viz. amino acids and monosaccharides. Methods to fully hydrolyze peptides, proteins, oligo- and polysaccharides are known in the art. Preferably, a coffee bean ofthe invention contains at least 22 g / kg, preferably at least 23 g / kg, more preferably at least 23.5 g / kg, even more preferably at least 24.0 g / kg, and most preferably offrom 24.0 to 27.5 g / kg oforganic acids. Preferably, the organic acids are selected from the group consisting of citric acid, malic acid, quinic acid, glycolic acid, formic acid, lactic acid, fumaric acid, shikimic acid, succinic acid, and acetic acid. Preferably, a coffee bean ofthe invention contains at most 0.3 g / kg, preferably at most 0.2 g / kg, and most preferably at most 0.1 g / kg, ofeach organic acid selected from the group consisting ofglycolic acid, formic acid, lactic acid, fumaric acid, shikimic acid, and succinic acid. Preferably, a coffee bean ofthe invention contains at most 5.0 wt%, preferably at most 4.5 wt%, more preferably at most 4.3 wt%, ofchlorogenic acids. Preferably, the chlorogenic acid is selected from the group consisting of3-CQA, 5-CQA, 3-FQA, 4-CQA, 5-FQA, 4-FQA, 3.4-diCQA, 3.5-diCQA, and 4.5-diCQA. Therein, CQA denotes caffeoquuinic acid, FQA denotes feruloquuinic acid, and diCQA denotes dicaffeoquuinic acid. Preferably, a coffee bean ofthe invention contains at most 0.40 wt%, preferably at most 0.35 wt%, more preferably at most 0.32 wt%, and most preferably offrom 0.20 to 0.32 wt%, of3-CQA. Preferably, a coffee bean ofthe invention contains at most 0.60 wt%, preferably at most 0.52 wt%, more preferably at most 0.47 wt%, and most preferably offrom 0.35 to 0.47 wt%, of4-CQA. Preferably, a coffee bean ofthe invention contains at most 0.20 wt%, preferably at most 0.15 wt%, more preferably at most 0.10 wt%, and most preferably offrom 0.01 to 0.10 wt%, of4-FQA. Preferably, a coffee bean ofthe invention contains most 3.0 wt%, preferably at most 2.7 wt%, more preferably at most 2.4 wt%, and most preferably offrom 1.5 to 2.4 wt%, of5-CQA. Preferably, a coffee bean ofthe invention contains most 0.50 wt%, preferably at most 0.40 wt%, more preferably at most 0.35 wt%, and most preferably offrom 0.20 to 0.35 wt%, of5-FQA. Preferably, a coffee bean ofthe invention contains sugar. Preferably, the sugar is selected from the group consisting of arabinose, galactose, glucose, sucrose, xylose, mannose, and fructose. Preferably, a coffee bean ofthe invention contains an amount offree sugar of at most 7.5 wt%, more preferably at most 6.0 wt%, even more preferably at most 5.5 wt%, and most preferably in a range offrom 4.5 to 5.5 wt%. Preferably, a coffee bean ofthe invention contains a total weight of monosaccharides of at most 35 wt%, more preferably at most 32 wt%, even more preferably at most 30 wt%, and most preferably in a range offrom 25 to 30 wt%. Preferably, the monosaccharide is selected from the group consisting of arabinose, galactose, glucose, xylose, mannose, and fructose. Preferably, a coffee bean ofthe invention contains (ii) at least 0.15 wt%, preferably at least 0.20 wt%, more preferably at least 0.22 wt%, and most preferably offrom 0.22 to 0.35 wt%, offree glucose. Preferably, a coffee bean ofthe invention contains at least 3.0 wt%, preferably at least 3.5 wt%, more preferably at least 4.0 wt%, and most preferably offrom 4.0 to 5.5 wt%, oftotal glucose. Preferably, a coffee bean ofthe invention contains at most 6.0 wt%, preferably at most 5.5 wt%, more preferably at most 5.0 wt%, and most preferably offrom 4.0 to 5.0 wt%, offree sucrose. Preferably, a coffee bean ofthe invention contains a total weight ofamino acids of at most 17 wt%, preferably at most 15 wt%, more preferably at most 13 wt%, and most preferably in a range offrom 11 to 13 wt%. Preferably, a coffee bean ofthe invention contains at most 0.30 wt%, preferably at most 0.25 wt%, more preferably at most 0.23 wt%, and most preferably offrom 0.15 to 0.21 wt%, offree amino acids. Preferably, a coffee bean ofthe invention contains at most 0.05 wt%, preferably at most 0.04 wt%, more preferably at most 0.03 wt%, and most preferably offrom to 0.005 to 0.03 wt%, offree alanine. Preferably, a coffee bean ofthe invention contains at most 0.06 wt%, preferably at most 0.05 wt%, more preferably at most 0.04 wt%, and most preferably offrom to 0.005 to 0.04 wt%, offree asparagine. Preferably, a coffee bean ofthe invention contains at most 0.03 wt%, preferably at most 0.02 wt%, and most preferably at most 0.01 wt%, offree proline. Preferably, a coffee bean ofthe invention contains at most 0.03 wt%, preferably at most 0.02 wt%, and most preferably at most 0.01 wt%, offree serine. Preferably, a coffee bean ofthe invention contains at most 0.03 wt%, preferably at most 0.02 wt%, and most preferably at most 0.01 wt%, offree tryptophan. Preferably, a coffee bean ofthe invention contains at most 0.03 wt%, preferably at most 0.02 wt%, and most preferably at most 0.01 wt%, offree y-aminobutyric acid. Preferably, a coffee bean ofthe invention contains at most 0.03 wt%, preferably at most 0.02 wt%, and most preferably at most 0.01 wt%, ofeach free amino acid selected from the group consisting ofproline, serine, tryptophan, y-aminobutyric acid, threonine, glutamine, glycine, valine, methionine, isoleucine, leucine, tyrosine, ornithine, lysine, histidine, arginine, taurine, hydroxyproline, cysteine, cystine, and hydroxylysine. The invention also relates to roasted coffee beans and roasted ground coffee that are prepared from the coffee beans ofthe invention and coffee beverages prepared from said roasted ground coffee. Standard methods to roast coffee beans and grind the roasted coffee beans into roasted ground coffee, as well as standard methods to prepare a coffee beverage from roasted ground coffee are known to the skilled person. Arrangement The invention also relates to an arrangement for growing a plant ofthe genus Coea under such conditions that within 160 days, preferably within 130 days, more preferably within 120 days, the plant has a total leafarea per plant of at least 725 cm2. The arrangement comprises the plant material and a lighting device congured to provide articial grow light to the plant material. The articial grow light is preferably as dened herein. Preferably, the lighting device is congured to communicate with a light controller congured to control the lighting device. In principle, any suitable light source can be used. However, preferably the lighting device comprises one or more light-emitting diodes (LEDs). More preferably, the lighting device comprises a light-emitting diode congured to provide the red component as dened herein. More preferably, the lighting device comprises a light-emitting diode congured to provide the blue component as dened herein. More preferably, the lighting device comprises a light-emitting diode congured to provide the far-red component as dened herein. Even more preferably, the lighting device comprises a light-emitting diode congured to provide the red component as dened herein, and a light-emitting diode congured to provide the blue component as dened herein. Most preferably, the lighting device comprises a light-emitting diode congured to provide the red component as dened herein, a light-emitting diode congured to provide the blue component as dened herein, and a light-emitting diode congured to provide the far-red component as dened herein. The arrangement preferably further comprises an air temperature adjustment device congured to adjust the air temperature. During operation the air temperature adjustment device may be used to maintain the air temperature at a temperature as dened above. Temperature adjustment devices such as heating and cooling adjustment devices are well- known to the skilled person. Preferably, the air temperature adjustment device is congured to communicate with an air temperature controller. The air temperature controller is congured to control the air temperature adjustment device. Preferably, the arrangement further comprises an air temperature sensor congured to measure the air temperature. Preferably, the air temperature sensor is congured to communicate with the air temperature adjustment device and / or the air temperature controller. Preferably, the air temperature controller is congured to control the air temperature adjustment device in dependence ofcommunication received by the air temperature controller from the air temperature sensor. The arrangement preferably further comprises a substrate temperature adjustment device congured to adjust the substrate temperature. During operation the substrate temperature adjustment device may be used to maintain the substrate temperature at a temperature as dened above. Temperature adjustment devices such as heating and cooling adjustment devices are well-known to the skilled person. Preferably, the substrate temperature adjustment device is congured to communicate with a substrate temperature controller. The substrate temperature controller is congured to control the substrate temperature adjustment device. Preferably, the arrangement further comprises a substrate temperature sensor congured to measure the substrate temperature. Preferably, the substrate temperature sensor is congured to communicate with the substrate temperature adjustment device and / or the substrate temperature controller. Preferably, the substrate temperature controller is congured to control the substrate temperature adjustment device in dependence of communication received by the substrate temperature controller from the substrate temperature sensor. Preferably, the arrangement further comprises a humidity adjustment device congured to adjust the relative humidity. During operation the humidity adjustment device may be used to maintain the relative humidity as dened above. For example, the humidity adjustment device may absorb and / or release moisture from the air to adjust the relative humidity. Preferably, the humidity adjustment device is congured to communicate with a humidity controller. The humidity controller is congured to control the humidity adjustment device as dened herein. During operation, the humidity controller and the humidity adjustment device may be used to maintain the relative humidity as dened above. Preferably, the arrangement further comprises a humidity sensor congured to measure the relative humidity. Preferably, the humidity sensor is congured to communicate with the humidity adjustment device and / or the humidity controller. Preferably, the humidity controller is congured to control the humidity adjustment device in dependence ofcommunication received by the humidity controller from the humidity sensor. Preferably, the arrangement comprises a C02 adjustment device congured to adjust the C02 concentration of air. During operation the C02 adjustment device may be used to maintain the C02 concentration of air as dened above. For example, the C02 adjustment device may absorb and / or release carbon dioxide from or to the air to adjust the C02 concentration ofthe air. Preferably, the C02 adjustment device is congured to communicate with a C02 controller. The C02 controller is congured to control the C02 adjustment device as dened herein. During operation, the C02 controller and the C02 adjustment device may be used to maintain the C02 concentration in the air as dened above. Preferably, the arrangement further comprises a C02 sensor congured to measure the C02 concentration in the air. Preferably, the C02 sensor is congured to communicate with the C02 adjustment device and / or the C02 controller. Preferably, the C02 controller is congured to control the C02 adjustment device in dependence ofcommunication received by the C02 controller from the C02 sensor. Preferably, the arrangement comprises a conductivity adjustment device congured to adjust the electrical conductivity ofthe substrate. It will be understood that ifherein reference is made to conductivity without the adjective electrical, electrical conductivity is nevertheless meant. During operation the conductivity adjustment device may be used to maintain the electrical conductivity ofthe substrate as dened above. For example, the conductivity adjustment device may absorb and / or release water and / or salts from or to the substrate to adjust the electrical conductivity. Preferably, the conductivity adjustment device adjusts the electrical conductivity ofthe water that is provided to the substrate. Preferably, the conductivity adjustment device is congured to communicate with a conductivity controller. The conductivity controller is congured to control the conductivity adjustment device as dened herein. During operation, the conductivity controller and the conductivity adjustment device may be used to maintain the electrical conductivity as dened above. Preferably, the arrangement further comprises a conductivity sensor congured to measure the electrical conductivity. Preferably, the conductivity sensor is congured to communicate with the conductivity adjustment device and / or the conductivity controller. Preferably, the conductivity controller is congured to control the conductivity adjustment device in dependence ofcommunication received by the conductivity controller from the conductivity sensor. Preferably, the arrangement comprises apH adjustment device congured to adjust the pH ofthe substrate. During operation the pH adjustment device may be used to maintain thepH ofthe substrate as dened above. For example, thepH adjustment device may absorb and / or release water, acidic substances, and / or basic substances from or to the substrate to adjust the pH. It will be understood that basic as used herein refers to Bronsted bases. Preferably, thepH adjustment device adjusts thepH ofthe water that is provided to the substrate. Preferably, the pH adjustment device is congured to communicate with apH controller. ThepH controller is congured to control thepH adjustment device as dened herein. During operation, thepH controller and thepH adjustment device may be used to maintain thepH ofthe substrate as dened above. Preferably, the arrangement further comprises apH sensor congured to measure the pH ofthe substrate. ThepH ofthe substrate can be measured directly on the substrate, but it is preferred that the pH ofthe substrate is determined by measuring the pH ofthe water provided to or obtained from the substrate. Preferably, thepH sensor is congured to communicate with thepH adjustment device and / or the pH controller. Preferably, thepH controller is congured to control the pH adjustment device in dependence of communication received by thepH controller from thepH sensor. Most preferably, the arrangement further comprises the air temperature adjustment device, the substrate temperature adjustment device, the humidity adjustment device, the C02 adjustment device, the conductivity adjustment device, and the pH adjustment device. It will be understood that one adjustment device may be congured to adjust more than one parameter. As such, the C02 adjustment device may for example also be congured to adjust the relative humidity, and / or the air temperature. Likewise, thepH adjustment device may for example also be congured to adjust the electrical conductivity ofthe substrate. In other words: the various adjustment devices as disclosed herein may be combined, preferably integrated. Most preferably, the arrangement further comprises the air temperature sensor, the substrate temperature sensor, the humidity sensor, the C02 sensor, the conductivity sensor, and the pH sensor. It will be understood that the aforementioned adjustment devices and the aforementioned sensors may be integrated, in particular such that a respective sensor is integrated with a respective adjustment device. For example, thepH sensor may be comprised in thepH adjustment device. Alternatively, the sensor and the adjustment device are physically separated. This may reduce the inuence ofthe adjustment device on the measurements ofthe sensor, eg. ifthe adjustment device releases acid to adjust the pH the concentration of acid close to the adjustment device may be temporarily high as the acid diffuses into the substrate. Preferably, the arrangement further comprises the air temperature controller, the substrate temperature controller, the humidity controller, the C02 controller, the conductivity controller, and / or the pH controller. More preferably, the arrangement further comprises the air temperature controller, the substrate temperature controller, the humidity controller, the C02 controller, the conductivity controller, and thepH controller. It will be understood that the communication between the controller and the respective (adjustment) device and / or sensormay be via wires or wireless, wherein wireless communication is preferred. Preferably, the (adjustment) device and / or the sensor are provided with telecommunication means congured to exchange signals and / or message with the controller. As such, the controllermay be able to communicate with the (adjustment) device and / or sensor from a remote location. It is however preferred that the controller is at the same location as the (adjustment) device and / or sensor, viz. that the controller and the (adjustment) device and / or sensor are at most 500 meters away from each other, more preferably at most 250 meters, more preferably at most 100 meters, and most preferably at most 50 meters. Plant cultivation facility The invention also relates to a plant cultivation facility comprising the arrangement ofthe invention. Preferably, the plant cultivation facility comprises a controlled condition environment that is substantially daylight-free. Preferably, the plant material, the one or more adjustment devices, and / or the one or more sensors as dened herein are kept within said controlled condition environment. Preferably, the controlled condition environment comprises one or more ofdaylight shielding, heat insulation, and moisture shielding. It will be understood that it is not required that the one or more controllers as dened herein are also present in the plant cultivation facility. The one or more controllers may communicate with the one or more adjustment devices via wires or wirelessly, and therefore may communicate remotely. & The invention also pertains to the use of articial light to accelerate the growth ofplant material of a plant ofthe species Coea, wherein preferably substantially exclusively articial grow light is used, wherein preferably said articial grow light is as dened herein. Preferably, the plant ofthe species Coea is selected from the group consisting of seedlings, cuttings, tissue culture plants, and young plants. Likewise, preferably the other conditions ofthe method ofthe invention are used, in particular the carbon dioxide concentration ofthe air, thepH ofthe substrate, the electric conductivity ofthe substrate, the relative humidity ofthe air, and the temperature, in particular the substrate temperature and / or the space temperature. Denitions The term about as used herein preferably indicates a deviation of25% or less from the given value, more preferably 20% or less, more preferably 15% or less, more preferably 10% or less, and most preferably 5% or less. In particular, when referring to the rst about 2 days or rst about 4 days and the likewhen the starting material is a cutting or a tissue culture plant, about preferably means a deviation of25% or less. In particular, when referring to specic values for the air temperature, substrate temperature, pH ofthe substrate, carbon dioxide concentration ofthe air, the electric conductivity ofthe substrate, or the relative humidity ofthe air, about preferably means a deviation of10% or less, most preferably 5% or less. Examples The invention is illustrated below using several examples. It will be understood that the invention is not limited thereto, and other embodiments such as those listed above are also capable ofachieving the technical effects and benets ofthe invention. Example 1 General information In Example 1 general information is provided applicable for procedures 1A, 1B, 2A, and 2B, according to the invention. Procedures2A and 2B start with a cutting or a tissue culture plant of a coffee plant. By contrast, procedures 1A and 1B start with providing a seed of a coffee plant, sowing said seed in a suitable horticultural substrate, and allowing the seed to germinate. The germinating seed was kept indoors under controlled conditions. Germination was carried out using the following conditions. Both the space temperature and the substrate temperature were maintained in a range offrom 27 to 33 °C, typically at about 30°C. The relative humidity ofthe airwas maintained in a range offrom 85 to 95%, typically at about 90%. The carbon dioxide concentration in the airwas maintained in a range offrom 300 to 650 ppm, typically at about 420 ppm. The seed was sowed in a container having avolume in a range offrom 65-130 mL, typically 95 mL. No lightwas applied. Germination took about 30 days, afterwhich a seedling was obtained. Unless indicated otherwise, the following conditions were applied for the rest of procedures 1A and 1B, and throughout procedures 2A and 2B. The coffee plants were kept indoors, in a controlled condition environment that was substantially daylight-free. This controlled condition environment comprised a lighting device (in particular lighting devices comprising one or more light-emitting diodes), an air temperature adjustment device, a substrate temperature adjustment device, a humidity adjustment device, a C02 adjustment device, apH adjustment device, a conductivity adjustment device, an air temperature sensor, a substrate temperature sensor, a humidity sensor, a C02 sensor, apH sensor, and a conductivity sensor. All adjustment devices and sensors are as dened herein, and were congured to communicate with one or more controllers. The coffee plants were exposed to articial grow light for about 12-18 hours a day, typically 14 hours a day, for a total duration ofup to 210 days. The C02 concentration was kept within the range offrom 420-2000 ppm, typically at about 1500 ppm. A suitable horticultural substrate was used, and a suitable horticultural nutrient solution was applied when necessary. The electrical conductivity ofthe soil in which the coffee plants grewwas maintained in a range offrom 1.2-2.8 mS / cmz, typically at about 2.0 mS / cmz, and the pH of said soil was maintained in a range offrom 5.2-6.6, typically at aboutpH 5.9. The temperature ofboth the soil and the (shoots ofthe) coffee plantwere maintained in a range offrom 24-32 °C, typically at about 27 or 29 °C. The relative humidity ofthe airwas maintained in a range offrom 75-85%, typically at about 80%. Optionally, one or more of the side branches were pruned. For procedures 1A and 1B, the plants were kept in a container with avolume in a range of from 65-130 mL, typically 95 mL, for the rst about 58-64 days (not including germination). On about day 58-64, the plants were repotted to a container with avolume in a range offrom 300-1000 mL, typically 750 mL, or to a container with avolume in a range offrom 500-1500 mL, typically 1000 mL. For procedures 2A and 2B, the plants were put in a container with avolume in a range offrom 65-130 mL, typically 95 mL, for the rst about 39-45 days. On about day 39-45, the plants were repotted to a container with avolume in a range offrom 300-1000 mL, typically 750 mL, or to a container with avolume in a range offrom 500-1500 mL, typically 1000 mL. Moreover, ifreference is made to light having a red component, it is meant that a light source was used producing light with wavelengths in a range offrom 600-700nm with a peak at 660 nm, wherein the light intensities at 600 and 700nm are less than2% ofthe light intensity at said peak. Likewise, for light having a blue component a light source was used producing light with wavelengths in a range offrom 400-500nm with a peak at 450 nm, wherein the light intensities at 400 and 500nm are less than 1% ofthe light intensity at said peak. Finally, for light having a far-red component a light source was used producing light with wavelengths in a range offrom 680-800nm with a peak at 730-740 nm, wherein the light intensity at 680nm is less than 6% ofthe light intensity at said peak, and the light intensity at 800nm is less than2% ofthe light intensity at said peak. Example 2 Below, more details are provided for procedures 1A, 1B, 2A, and 2B according to the invention. In each procedure, the growth ofa coffee plant is accelerated by exposing said coffee plant substantially exclusively to articial grow light. In procedures 1A and 2A, the articial grow light consists essentially of a red component and a blue component, while in procedures 1B and 2B the articial grow light consists essentially of a red component, a blue component, and a far-red component. Table 1 lists the composition ofthe articial grow light used in procedures 1A and 1B. Likewise, Table 2 lists the further conditions used in procedures 2A and 2B. As explained above, procedures 1A and 1B use seedlings as a starting material, while Procedures2A and 2B use cuttings or tissue culture plants as a starting material. Table 1. Composition ofartificialgrow light usedinprocedures [A and IB. dddddddddddddddd Fddddddddddddd d o PA__ 2 Table 2. Composition ofartificialgrow light, temperatures, andrelative humidity, used in procedures 2A and2B. ___-- Parameter Target Range Target Range Target Range Target Range value value value value Blue 11th 35 10-60 35 10-60 50 30-80 70 50-100 (umol / m / s) ' 180- Redhth 110 30-140 110 30-140 155 75-240 220 (umol / m / s) 300 light 21806 temperature 19-25 22-28 sub 20 17-23 22 19-25 25 22-28 27 24-32 temperature (°C) Relatwe humldlty 85-95 85-95 85 80-90 75-85 (%) Example 3 Results and comparison Below, the results are shown ofProcedures 1A, 2A, 1B, and 2B ofthe invention. Table 3 summarizes the growth methods and their differences. Table 4 lists the differences in plant quality obtainedwhen applying the procedures ofthe invention for various amounts oftime. From Table 4 it is evident that the procedures ofthe invention lead to plants of a higher quality, that are also obtained faster than in the reference example. As mentioned above, when growing ayoung plant uncontrolled outdoors, on average, it takes about 160-240 days from sowing (so including time for germination) to obtain such a young plantwhich only has about seven leafpairs with a total leafarea per plant ofwell below 700 cm2, and are only about 20-45 cm tall. Table 3. Growth methodsandthe time requiredto obtain ayoungplant. - Exposed to artificial es es es es grow light? y y y y . . cuttin or tissue cuttin or tissue Starting material seed seed g g culture plant culture plant Grown indoors or . . . . 1ndoors 1ndoors 1ndoors 1ndoors outdoors? Da 5 re uired to obtain about about y q a a about 100 about 100 young plant 120 120 a including time for germination. Table 4. Dierences inplant quality obtainedwhen applying theprocedures ofthe inventionfor various amounts oftime. The number ofdaysforprocedures [A and[B includes 30 daysfor germination. Typicalranges are givenfor certainplantproperties, and the typical values are indicatedbetweenparentheses. -__ Number of 120 160 195 160 160 100 140 175 140 140 days without 130 165 130 130 n / a n / a n / a n / a n / a germination Total leaf area 450- 1000- 1600- 1100- 1100- 450- 1000- 1600- 1100- 1100- per plant (cm2) 1050 2000 2600 2100 2100 1050 2000 2600 2100 2100 (750) (1500) (1960) (1600) (1500) (750) (1500) (1960) (1600) (1500) Total dry 3.5-7.5 7-13 11-17 8-14 7-13 3.5-7.5 7-13 11-17 8-14 7-13 weight of entire (5.5) (10) (14) (11) (10) (5.5) (10) (14) (11) (10) Plant (g) Ratio ofshoot 110.5 110.5 110.5 110.5 110.5 110.5 110.5 110.5 110.5 110.5 over root 1;0_2 110.2 102 102 110.2 1:02 102 110.2 1;0_2 110.2 (ing dry weight (1:03) (1103) (1:03) (1:03) (1103) (1:03) (1:03) (1103) (1:03) (1103) / g dry weight) Height of plant 15-50 25-65 65-115 81-125 100-150 15-50 25-65 65-115 81-125 100-150 (cm) (25) (35) (80) (100) (120) (25) (35) (80) (100) (120) Average 2-7 (3.5) 2-7 (3.5) 4-8 (5.7) 6-14 6-14 2-7 (35) 2-7 (3.5) 4-8 (5.7) 6-14 6-14 internode (10) (10) (10) (10) length (cm) Number of leaf 6-8 (7) 9-11 14-18 9-11 10-14 6-8 (7) 9-11 14-18 9-11 10-14 pairs on the (10) (16) (10) (12) (10) (16) (10) (12) main stem Number of side 0-1 (0) 2-4 (3) 0-4 (3) 0-1 (0) 2-4 (3) 0-4 (3) branch pairs In the procedures for obtaining these plants, the space and substrate temperature were maintained in a range offrom 24-30°C, typically about 27°C throughout the procedure. b In the procedures for obtaining these plants, the space and substrate temperature were maintained in a range offrom 24-30°C, typically about 27°C, for the first about 30 days (without germination), and thereafter in a range offrom 26-32°C, typically about 29°C. ° In the procedures for obtaining these plants, the space and substrate temperature were maintained in a range offrom 24-30°C, typically about 27°C from about day 8 onwards. d In the procedures for obtaining these plants, the space and substrate temperature were maintained in a range offrom 24-30°C, typically about 27°C, from about day 8 until about 37, and thereafter in a range offrom 26- 32°C, typically about 29°C. °For these plants the side branches are pruned, typically within about three weeks ofthe formation ofthe side branch. Example 4 Analysis ofcoffee beans ofplants grown with the methods ofthe invention Fruit-bearing plants were grown with a method according to the invention. A coffee plant was grown within 160 days (including germination) using the method ofprocedure 1A as shown in Table 4. Thereafter, the coffee plantwas grown indoors, applying the standard conditions and the conditions ofTable 5. The plants were not exposed to far-red light. The concentration ofCO2 was typically maintained in a range offrom 420-2000 ppm, typically at about 1500 ppm. The plants were kept in pots having avolume oftypically 8.2-10.2 L, typically about 9.2 L. The electrical conductivity was typically maintained at about 1.7-3.3 mS / cmz, typically at about 2.5 mS / cmz. The pH ofthe substrate was typically maintained at 5.1-6.5, typically at about 5.8. Starting on day 547 after sowing, a 14-days period ofdrought stress was started. During this period, the amount of available water in the potwas reduced by reducing the watering (incl. nutrition) until a target weight ofthe pot is reached. Then, small amounts ofwater were applied to keep the weight in the determined range. After the drought stress the pots were rewatered with several liters ofwater, afterwhich the same watering regime as before the drought stress was followed. Table 5. Composition ofarticial grow light usedin togrowing bean-producingcoee plants using the methodofthe invention. The typicalrange ofvalues is givenand the specific value is indicatedbetweenparentheses. Bud Bud induction and Cherry induction owering development Red light (umol / mz / s) 200-300 200-300 (220) 200-300 (220) (220) Temperature at crop level and _ _ substrate temperature (°C) 24 30 (27) 24 30 (27) Night 13-19 (16) Relative humidity (%) 75-85 (80) 75-85 (80) On day 803 the fruitwas harvested, and coffee beans were isolated from said fruit. The contents ofthe coffee beans were analyzed using standard techniques in the art. Reference samples from coffee beans obtained from traditionally grown coffee were analyzed using the same techniques. This analysis showed that coffee beans obtained from plants grown using a method ofthe invention had higher total amounts oforganic acids and / or glucose, and lower total amounts of sugar, amino acids, and / or chlorogenic acids, as compared to traditionally grown coffee. In particular, the coffee beans ofthe invention contained lower amounts of 3-CQA, 4-CQA, 4-FQA, 5-CQA, and / or 5-FQA, as compared to traditionally grown coffee, whereinCQA denotes caffeoquuinic acid, andFQA indicates feruloquuinic acid. Moreover, coffee beans ofthe invention contained lower amounts offree amino acids, as compared to traditionally grown coffee, wherein the free amino acids were alanine, ragine, proline, serine, tryptophan, and y-aminobutyric acid. The analysis results ofthe fee beans ofthe invention is shown below in Table 6 (wet weights) and Table 7 (dry hts). Furthermore, the coffee beans ofthe invention were found to be less bitter than fee beans obtained from traditionally grown coffee beans. le 6. Composition ofcoee beans obtainable bya methodofthe invention. The weight centagesandweights are as comparedto the wetweight ofthe composition, which ludes moisture. The moisture content ofthe coee beanswas about 14.8 wt%. Chlorogenic Amino acids 1 100_ (- k-) acids (th0) _ A d... alic ' acid 4.5 5 -CQA 1.91 Galactose <0.1 9.1 Threomne < 0.01 0.36 . all maric 3.4- . um ikimic 3.5- . ccinic 4.5- . ac1d mono Total di mono / d1 Phen lalanine bu nc ac1d mum 10.44 aThe total amount of sugars and amino acids refers to the amounts ofmonosaccharides and amino acids obtained after full hydrolysis of all oligo- and polysaccharides, peptides, proteins, and the like, in the sample. Hence, the total of sucrose is listed as n / a, since sucrose is not a monosaccharide and is hydrolyzedwhen determining the total amount ofmonosaccharides. Table 7. Composition ofcoee beans obtainable bya methodofthe invention. The weight percentagesandweights are as comparedto the dry weight ofthe composition, excluding moisture. The moisture content ofthe coee beanswas about 14.8wt%. Organic acids Chlorogenic Suars (wt%) Amino acids (_ 100 _) (g / kg) acids (wt%) 3 -CQA 5 -CQA 10.68 .-A m d -FQA Fumaric 3 .4- . Shikimic 3 .5- . Succinic 4.5- . mono mono / d1 Phen lalanine bu nc ac1d rolme 1 sme 12.25 The total amount of sugars and amino acids refers to the amounts ofmonosaccharides and amino acids obtained after full hydrolysis of all oligo- and polysaccharides, peptides, proteins, and the like, in the sample. Hence, the total of sucrose is listed as n / a, since sucrose is not a monosaccharide and is hydrolyzedwhen determining the total amount ofmonosaccharides.

Claims

1. A method for growing a plant of the genus Coffea under such circumstances that within 160 days, preferably within 130 days, the plant has a total leaf area per plant of at least 725 cm², where the method comprises the steps of: a) providing plant material of a plant of the genus Coffea, where the plant material is selected from the group consisting of a seedling, a cutting, and a tissue culture plant; whereby the seedling is preferably obtained by providing of a seed and the germination of said seed; and b) exposing said plant material to light, whereby the said light is substantially exclusively artificial grow light.

2. The method according to conclusion 1, whereby the artificial grow light a red component with a go length in the range of 600 to 700 nm comprises, and where the red component has a photosynthetic ux density has a level of at least 30 µmol / mZ / s; preferably in a range of 30 to and with 1000 µmol / m² / s.

3. The method according to one of the preceding conclusions, whereby the artificial grow light a far-red component with a go length in a range from 680 to 800 nm includes, preferably from 680 to 770 nm, and where the far-red component is a photosynthetic has a ux density of at least 1 µmol / m² / s; preferably in a range from 1 to 100 µmol / m² / s.

4. The method according to claims 2 and 3, whereby the artificial grow light mentioned red component and mentioned far-red component includes, where the ratio of the photosynthetic ux density of mentioned red component regarding the photosynthetic ux density of the said far-red component lies in a range of 1:1 up to and including 60:

1.

5. The method according to one of the preceding conclusions, whereby the artificial grow light a blue component with a go length in a range from 400 to 500 nm includes, preferably from 420 to 495 nm, and where the blue component has a photosynthetic ux density has a level of at least 10 µmol / mZ / s; preferably in a range of 10 to with 250 µmol / mZ / s.

6. The method in accordance with one of the preceding conclusions, whereby said plant material is exposed to the said light for ten at least 8 hours per day; with a greater preference for a duration in a range of 8 up to and including 24 hours a day.

7. The method in accordance with one of the preceding conclusions, whereby said plant material at a temperature in a range of 15 up to and including is kept at 40 °C; preferably in a range of 17 to 35 °C; with greater preference in a range of 18 to 32 °C; with most preferred in a range of 25 to 29 °C.

8. The method in accordance with one of the preceding conclusions, whereby said plant material is exposed to a relative humidity in a range of 60 to 100%; preferably in a range from 67 to 97%; with more preference in a range of 70 to and with 95%; with most preference in a range of 75 to 85%.

9. The method in accordance with one of the preceding conclusions, whereby The mentioned plant of the genus Coffea was chosen from the group consisting of Coffea arabica, Coffea canephora, and Coffea liberica.

10. The method according to one of the preceding conclusions, whereby said plant material is exposed to air with a CO2- concentration of at least 250 ppm; preferably in a range of 250 to and with 2750 ppm. 1 1. The method according to one of the preceding conclusions, whereby the working method is carried out internally; preferably for at least the first 90 days, preferably at least the first 120 days, with more preference at least the first 130 days, with most preference at least the first 160 days.

12. The method according to one of the preceding conclusions, whereby the The procedure is carried out for a maximum of 300 days, with greater preference at most 160 days; preferably at most 130 days; with more preference at most 120 days.

13. The method according to one of the preceding conclusions, whereby the the process is continued at least until the plant bears fruit that one or includes more coffee beans.

14. The method according to one of the preceding conclusions, whereby when the plant has a total leaf surface area per plant of at least 725 cm², the said plant is being moved to a field outside.

15. The method in accordance with one of conclusions 1 to 13, whereby the working method is carried out indoors at least until said plant bears fruit that contains one or more coffee beans.

16. A plant of the genus Coffea obtainable by the method according to one of the preceding conclusions; whereby the said plant at preference: a) a total leaf area per plant of at least 725 cm2; at preference in a range of 725 to 4000 cm2; b) a total dry weight of at least 5.5 grams; preferably in a range of 6.0 to 50 grams; c) an average internode length of at least 3.5 cm; preferably in a range of 4 to 17 cm; d) an average leaf area per leaf pair of at least 125 cm²; preferably in a range of 125 to 300 cm²; e) a height of at least 35 cm; preferably in a range of 40 up to and including 200 cm; f) a ratio of the dry weight of the shoot over the dry weight of the root of at least 1:0.6; preferably in a range from 1:0.6 to 1:0.05; and / or g) a number of leaf pairs on the main stem of at least 6, at preference in a range of 6 to 18; has, where if the plant has a height of 40 to 45 cm, the said plant furthermore has one or more of the characteristics a)-d), f) and g).

17. A plant within the meaning of claim 16, where the plant bears fruit that one or includes more coffee beans.

18. A coffee bean obtainable from the plant according to conclusion 17.

19. A coffee bean with: (i) at least 22 g / kg, preferably at least 23 g / kg, organic acids; (ii) at least 0.15 wt.%, preferably at least 0.20 wt.%, free glucose; (iii) at least 3.0 wt.%, preferably at least 3.5 wt.%, total glucose; (iv) at most 5.0 wt.% preferably at most 4.5 wt.% chlorogenic acids; (v) at most 0.30 wt.% preferably at most 0.25 wt.%, free amino acids; (vi) at most 6.0 wt.%, preferably at most 5.5 wt.%, free sucrose; and / or (vii) at most 35 wt.%, preferably at most 32 wt.%, total weight of monosaccharides; where the weights and weight percentages are compared with the Dry weight of the coffee bean.

20. Roasted coffee beans or roasted ground coffee, whereby the roasted coffee beans or the roasted ground coffee are manufactured from the coffee bean according to one of the conclusions 18 and 19. 2 1. A coffee drink, in which the coffee drink is prepared from the roasted ground coffee according to conclusion 20.

22. An apparatus for growing a plant of the genus Coffea under such circumstances that within 160 days, preferably within 130 days, the plant has a total leaf area per plant of at least 725 cm², where the fixture comprises: a) the plant material as defined in one of claims 1 and 9; and b) a lighting device designed to artificial grow light provide to the plant material, whereby the artificial grow light is as defined in one of conclusions 1 to 5; and optionally an air temperature adjustment device configured to the to adjust air temperature; a substrate temperature- adjustment device configured to adjust the substrate temperature; a humidity adjustment device designed to the relative to adjust humidity; a COg adjustment device configured to to adjust the COg concentration of air; a pH adjustment device designed for the pH of the substrate on which the plant material is required to adjust; and / or a conductivity adjustment device designed to the electrical conductivity of the substrate on which it plant material is kept to adapt; and optionally an air temperature sensor configured to the to measure air temperature; a substrate temperature sensor configured to to measure the substrate temperature; a humidity sensor installed to measure the relative humidity; a COg sensor configured to the to measure the CO2 concentration of air; a pH sensor designed to measure the pH of to measure the substrate on which the plant material is kept; and / or a conductivity sensor designed to measure the electrical conductivity of the to measure the substrate on which the plant material is kept; and optionally an air temperature controller designed to the to control air temperature adjustment device; a substrate temperature controller designed to control the substrate temperature. to control an adjustment device; a humidity controller equipped to control the humidity adjustment device; a CO2- controller designed to control the COg adjustment device; a pH- controller designed to control the pH adjustment device; and / or conductivity controller designed to the conductivity- to control adaptation device.

23. A plant breeding facility comprising the establishment according to conclusion 22, whereby the planting facility preferably has a substantially sunlight-free is a conditioned growing environment.

24. Use of artificial light to accelerate the growth of plant material of a plant of the species Coffea; preferably substantially exclusively artificial grow light is used; preferably The artificial grow light mentioned is as defined in one of 1 through 5.