Horticulture lighting device, horticulture system, and method of providing horticulture light to a basil plant

Abstract

The invention provides a horticulture lighting device (1000) comprising: (i) a lighting system (100) configured to provide horticulture light (101) having a controllable spectral power distribution; and (ii) a control system (300) configured to control the spectral power distribution of the horticulture light (101); wherein in an operational mode of the horticulture lighting device (1000), the horticulture lighting device (1000) is configured to provide the horticulture light (101) according to an on-off time schedule, wherein an on-period (D) and an off-period (N) are applied consecutively, wherein the horticulture light (101) comprises: one or more first horticulture light (1011) comprising wavelengths selected from the range of 400-600 nm; red light (1012) comprising wavelengths selected from the range of 600-700 nm; and far-red light (1013) comprising wavelengths selected from the range of 700-800 nm. Wherein the on-period (D) lasts in the range of 12-20 hours, the off-period (N) lasts in the range of 4-12 hours, wherein the on-period (D) comprises an end-of-day period (EOD) at the end of the on-period (D), wherein the end-of-day period (EOD) lasts in the range of 0.5-4 hours. Wherein during most of the on-period (D) before the end-of-day period (EOD), the R / Fr ratio is selected from the range of 4-20, wherein the R / Fr ratio is defined as the ratio of the I600-700nm of the red light (1012) to the I700-800nm of the far-red light (1013), and during most of the end-of-day period (EOD), the R / Fr ratio is selected from the range of 0.1-4.

Description

Technical Field

[0001] This invention relates to a horticultural lighting device and a horticultural system including such a horticultural lighting device. The invention also relates to a method of providing horticultural light to plants, particularly basil plants (using such a horticultural lighting device or horticultural system). Background Technology

[0002] Industrial plant growth facilities and methods of using such plant growth facilities are known in the art. For example, US2018 / 0206422 describes an industrial plant cultivation facility for growing plants of at least one plant species, the facility comprising: an outer shell surrounding a growth chamber; a plurality of shelves placed within the growth chamber, each shelf configured to receive one or more trays; a plurality of trays placed within the shelves, the trays configured to receive a plurality of plants of the at least one plant species, and the trays configured to receive a growth medium; and a fluid system configured to supply the trays with a growth medium containing nutrients and having a pH, wherein the fluid system is configured to adjust the nutrient concentration and pH according to a predetermined nutrient concentration and a predetermined pH for the plant species. A climate system configured to provide temperature and humidity within the growth chamber, wherein the climate system is configured to adjust the temperature and humidity within the growth chamber according to a predetermined temperature and humidity for a plant species; a plurality of light-emitting diode (LED)-based lighting devices configured to provide a spectrum and light intensity, wherein the spectrum includes photosynthetically active radiation (PAR); and wherein the LED-based lighting devices are configured to adjust the light intensity and / or spectrum according to a predetermined light intensity and / or predetermined spectrum for a plant species; a carbon dioxide system configured to provide a carbon dioxide concentration within the growth chamber, wherein the carbon dioxide system is configured to adjust the carbon dioxide concentration according to a predetermined carbon dioxide concentration for a plant species; and a transport system for transporting pallets. Summary of the Invention

[0003] Plants use photosynthesis to convert light, CO2, and H2O into carbohydrates (sugars). These sugars are used to promote metabolic processes and biomass formation. This biomass formation can include stem elongation, increased leaf area, flowering, and fruit formation. Photosynthesis can involve one or more plant photoreceptors, such as chlorophyll. Photoreceptors may also be involved in other interactions between plants and radiation, such as photoperiodism, phototropism, and photomorphogenesis. Photoperiodism can refer to a plant's ability to sense and measure the period of radiation (e.g., inducing flowering); phototropism refers to the growth movement of a plant toward and / or away from radiation; and photomorphogenesis refers to morphological changes that occur in response to the wavelength and intensity of radiation.

[0004] The two important absorption peaks of chlorophyll a and b can be located in the red and blue region, in particular between 625-675 nm and 425-475 nm, respectively. In addition, other local peaks can also be present in the near ultraviolet (300-400 nm) and far red region (700-800 nm). The main photosynthetic activity appears to take place in the wavelength range of 400-700 nm. Radiation in this range is referred to as photosynthetically active radiation (PAR).

[0005] In horticulture lighting, near ultraviolet light is defined as one or more wavelengths selected from the spectral range of 300-400 nm, blue is defined as one or more wavelengths selected from the spectral range of 400-500 nm, white is defined as wavelengths selected from the spectral range of 400-700 nm (these selected wavelengths together can constitute white light, for example a combination of wavelengths in blue and green and red), green is defined as one or more wavelengths selected from the spectral range of 500-600 nm, red is defined as one or more wavelengths selected from the spectral range of 600-700 nm, deep red is defined as one or more wavelengths selected from the spectral range of 640-700 nm, far red is defined as one or more wavelengths selected from the spectral range of 700-800 nm. Thus, deep red is a sub-range of red.

[0006] Photosensitive processes in plants can also be particularly relevant to phytochromes, a class of receptors. Phytochrome activity can direct different responses, such as leaf expansion, shade avoidance, stem elongation, seed germination, and flowering induction. Phytochromes can change their morphology depending on one or more (external) signals, for example upon exposure to one or more specific wavelengths of radiation, or upon exposure to a change in temperature. For example, a plant can comprise phytochromes having two morphologies, Pr and Pfr, which can be converted to the other morphology by absorbing light, and which have the following sensitivity peaks, respectively: a peak in red at about 660 nm and a peak in far red at about 730 nm.

[0007] In horticulture, light intensity can be measured in terms of photosynthetic photon flux density (PPFD), which refers to the number of photons per unit area per second (in units of µmol / sec / m 2 ; one mol corresponds to 6*10 23 photons). In practice, when applying for example intermediate lighting, the red PPFD used can typically be 200 µmol / sec / m 2and the ratio of blue: red can typically be 1 :7 (with red and blue especially selected from 625-675 nm, especially 400-475 nm, respectively). In particular, the photosynthetic photon flux density can comprise about 10% blue and about 90% red. The PPFD can be determined by a photodiode or directly measured with a photomultiplier tube. The area in the PPFD refers to the local light receiving (plant) area of the space in which the light source is arranged. In case of a multi-layer system, it can be defined as the area of the relevant layer included in the multi-layer configuration; the PPFD associated with each layer can then be estimated individually (see also below). In an embodiment, this area can be a value manually fed to the control unit, or in an embodiment, it can be evaluated by the control unit (e.g. using a sensor).

[0008] Plant growth can depend not only on the light intensity, but also on the spectral composition, duration and timing of the light to which the plant is exposed, among other parameters. In terms of these parameters, a combination of two or more parameter values is referred to as a "light recipe" for growing plants (or crops).

[0009] Light emitting diodes (LEDs) can play multiple roles in horticulture lighting, for example: (1) supplemental lighting: e.g. to supplement natural daylight to increase yield (e.g. of tomatoes) or to extend the crop yield during periods in which the price of the crop can be higher, such as in autumn, winter and spring; (2) photoperiodic lighting: the periodic duration of the light is important for many plants. For example, the duration and relative ratio of light and dark periods in a 24-hour cycle influences the flowering response of many plants. Controlling the durations and / or their ratio by means of supplemental lighting can help to regulate the flowering time; (3) artificial lighting: lighting for cultivation in a horticulture system that is not dependent on natural sunlight; (4) differential lighting: selecting lighting to promote cell differentiation, e.g. in the case of tissue culture.

[0010] In case the light that plants obtain from natural sunlight is insufficient, e.g. in northern regions or in so-called "plant factories" or "vertical farms" that rely entirely on artificial conditions and good control, it seems necessary to provide the plants with light for growth (leaves and fruits), maturation and conditioning before harvesting.

[0011] The available space for food production will become less and less. Therefore, innovations in production methods can be required to provide higher yields with less footprint, while becoming more sustainable (minimizing the use of energy and water). Producing food in a closed environment such as a plant farm is one way to meet these needs. In a plant farm (also known as a plant factory, vertical farm, or city farm), food can be grown in multiple layers, making better use of the available space than outdoor or greenhouse growing. This means that in a plant farm, not all plants can be illuminated by natural sunlight, and a large part of the light can need to come from artificial lighting. In a plant farm, it is desirable to always provide the best light treatment (to the plants). At the same time, it is desirable to use the light produced by the light sources as efficiently as possible to reduce energy consumption. In a plant farm, the yield per unit area can be much higher than in open fields. The use of water is minimized. Plant diseases and pests can be more easily prevented.

[0012] The term "horticulture" relates to the (intensive) cultivation of plants for human use, the activities of which are very diverse, including edible plants (fruits, vegetables, mushrooms, culinary herbs) and non-edible crops (flowers, trees and shrubs, lawn grass, hops, grapes, herbs). Horticulture is a branch of agriculture that involves the art, science, technology, and business of growing plants. It can include the cultivation of medicinal plants, fruits, vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweed, and non-edible crops such as grass and ornamental trees and plants. Here, the term "plant" is used to essentially refer to any species selected from medicinal plants, vegetables, herbs, sprouts, mushrooms, plants with nuts, plants with seeds, plants with flowers, plants with fruits, non-edible crops (e.g. grass and ornamental trees, etc.).

[0013] In this document, the term "plant" is used for essentially all stages of plant development. The term "plant part" can refer to roots, stems, leaves, fruits (if any), flowers (if any), etc.

[0014] The term "crop" can be used herein to refer to a plant species or variety that is planted to be harvested, for example, as food, livestock feed, fuel, or for any other economic purpose. The term "crop" can also refer to multiple crops. The term "plant" can also refer to a seed or seedling. Thus, the term "plant" can generally refer to any stage from seed to (mature) plant. The term "plant" can also refer to multiple (different) plants.

[0015] The term "horticulture light" can in particular herein refer to light having one or more wavelengths in one or more of a first wavelength region of 400-475 nm and a second wavelength region of 625-675 nm. The relative energy (watt) provided in these wavelength regions can depend on the environment and can for example depend on the type and / or growth stage of the plants. Hence, for one or more types of plants, a recipe can define the ratio of the different wavelengths of light in the horticulture light, (optionally) as a function of time. In particular, the term "horticulture light" can refer to the PAR wavelength region (photosynthetically active region of 400-700 nm). The term "horticulture light" can also be used for light applied to plants in hydroponic applications.

[0016] Further, the above can generally apply to (artificial) horticulture light. Further, in the present application, more specific horticulture light recipes are also presented. Further, in the present application, more specific horticulture lighting devices are also presented. In a specific embodiment, the light recipe can in particular comprise an on-time, in which horticulture light is provided, which can also be indicated as "daytime" or "light period", and an off-time, in which substantially no horticulture light is provided, which can also be indicated as "night" or "dark period".

[0017] Basil (Basilicum, or Ocimum basilicum or Basil) is a tropical plant used as a culinary herb. It is one of the most expensive and most widely sold herbs in the herb market. It is also a plant that is very sensitive to temperatures below 10°C. It is recommended to store it at 12°C. Storing at lower temperatures seems to cause the leaves to rot quickly, starting with small spots, the leaf surface becomes black. The product becomes quickly unsalable, which can mean a large waste for the supermarket and the consumer. To increase the so-called cold tolerance of basil, the only reliable solution seems to be never to store basil at temperatures below 12°C. Cold acclimation can be applied. However, it is observed that it is not always successful for all basil species. Storing basil at higher temperatures, for example 18°C (in a supermarket), basil will rot due to water loss and will wilt as quickly as when stored in cold conditions. In either case, there is no preferred cold or warm temperature other than the ideal of about 12°C. However, in general, a refrigerator is not designed for every crop and usually only a single temperature refrigerator is used for storing all herbs. However, other products are often transported and / or stored at other temperatures than the preferred temperature for basil. Hence, unfortunately, this plant seems to require a separate transport and handling from other herbs, which makes it both difficult and expensive. A solution to avoid the cold effect on basil would greatly improve the production chain.

[0018] It is therefore an aspect of the present application to provide an alternative horticulture system and / or apparatus and / or method which preferably further at least partially obviates one or more of above-mentioned drawbacks. It is an object of the present application to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0019] Thus, in a first aspect, the present application provides a horticulture lighting apparatus comprising: (i) a lighting system configured to provide horticulture light having a controllable spectral power distribution to a basil plant or "basil variety"; and (ii) a control system configured to control the spectral power distribution of the horticulture light. In particular embodiments, in an operational mode of the horticulture lighting apparatus, the horticulture lighting apparatus is configured to provide the horticulture light according to an on-off time schedule, wherein an on-period (D) and an off-period (N) are applied consecutively. In particular, in embodiments, the horticulture light comprises: one or more first horticulture light comprising wavelengths selected from the range of 400-600 nm; red light comprising wavelengths selected from the range of 600-700 nm; and far-red light comprising wavelengths selected from the range of 700-800 nm. Further, in embodiments, the on-period can last in the range of 12-20 hours, while the off-period lasts in the range of 4-12 hours. Further, in particular, the on-period comprises an end-of-day period (EOD) at the end of the on-period. In embodiments, the end-of-day period lasts in the range of at least about 0.25 hours, for example in the range of about 0.5-4 hours. Further, in particular, in embodiments, during at least part of the on-period preceding the end-of-day period, the R / Fr ratio is selected from the range of 4-20, wherein the R / Fr ratio is defined as the ratio of the intensity of red light (Ired) to the intensity of far-red light (Ifar-red) in the horticulture light. 600-700nm the intensity of far-red light (Ifar-red) in the horticulture light. 700-800nmFurthermore, especially in embodiments, the R / Fr ratio is chosen from the range of 0.1-4 during at least part of the end-of-day period (EOD). In embodiments, the R / Fr ratio during at least part of the on-period (D) is larger than the R / Fr ratio during at least part of the end-of-day period (EOD). Hence, the present invention especially provides in embodiments a horticulture lighting device comprising: (i) a lighting system configured to provide horticulture light having a controllable spectral power distribution, and (ii) a control system configured to control the spectral power distribution of the horticulture light; wherein in an operational mode of the horticulture lighting device, the horticulture lighting device is configured to provide the horticulture light according to an on-off time schedule, wherein an on-period and an off-period are applied consecutively, wherein (i) the horticulture light comprises: one or more first horticulture light comprising a wavelength selected from the range of 400-600 nm; red light comprising a wavelength selected from the range of 600-700 nm; and far-red light comprising a wavelength selected from the range of 700-800 nm, (ii) the on-period lasts in the range of 12-20 hours, while the off-period lasts in the range of 4-12 hours, wherein the on-period comprises an end-of-day period at the end of the on-period (D), wherein the end-of-day period lasts in the range of at least about 0.25 hours, especially in the range of 0.5-4 hours, (iii) wherein during at least part of the on-period preceding the end-of-day period, the R / Fr ratio is selected from the range of 4-20, the R / Fr ratio being defined as the ratio of the I 600-700nm of the red light and the I 700-800nm of the far-red light, and during at least part of the end-of-day period, the R / Fr ratio is chosen from the range of 0.1-4.

[0020] In the definition of the R / Fr ratio, the term I 600-700nm refers to the light intensity of the red light component in the horticulture light in µmol / m 2 / s of photons selected from the wavelength range of 600-700 nm, and the term I 700-800nm refers to the light intensity of the far-red light component in the horticulture light in µmol / m 2 / s of photons selected from the wavelength range of 700-800 nm. It is noted that the R / Fr ratio of the horticulture light is a property of the light produced and emitted by the lighting system, the lighting device or the lighting apparatus onto the plants.

[0021] To generate the claimed cold tolerance effect, the expressions "at least part of the on-period (or at least part on-period)" and "at least part of the end-of-day period (or at least part end-of-day period)" should be interpreted as a substantial part of the period, meaning at least 50%, preferably at least 80%, more preferably at least 90% of the period. In embodiments, the above expressions refer to substantially the entire duration of the period, i.e. substantially the entire on-period or substantially the entire end-of-day period.

[0022] With such an apparatus and / or using the method described herein (see also further below), it appears possible to improve cold tolerance. Several experiments with different lengths of time in which a substantial amount of far-red light is applied show that the end-of-day option can have a good impact on cold tolerance and can be a relatively energy-efficient solution. The inventors found that for the end-of-day period, there is a preferred range in which a substantial amount of far-red light is applied. On the one hand, increasing the period in which a substantial amount of far-red light is applied can substantially not further improve cold tolerance, but can lead to a more energy-consuming solution. On the other hand, significantly reducing the period in which a substantial amount of far-red light is applied can have a small or no impact on cold tolerance. The term "cold tolerance" specifically refers to the cold tolerance of the harvested basil plant, in particular the leaves thereof.

[0023] As mentioned above, the present application in particular provides a horticulture lighting apparatus. Such a horticulture lighting apparatus comprises at least a lighting system. The lighting system can comprise one or more light sources, in particular a plurality of light sources. Further, the light generated by the lighting system is controllable in one or more of spectral power distribution and spectral power, in particular at least in spectral power distribution. The lighting system is configured to provide light in one or more operational modes that is available to plants for growing, tying, ripening, etc. Hence, this light is also indicated herein as "horticulture light" (see also below).

[0024] In particular, the horticulture light can comprise one or more of: (a) a first horticulture light comprising wavelengths selected from the range of 400-600 nm, (b) a red light comprising wavelengths selected from the range of 600-700 nm, and (c) a far-red light comprising wavelengths selected from the range of 700-800 nm. In embodiments, the first horticulture light and the red light can together provide PAR light.

[0025] Hence, the horticulture lighting apparatus in particular comprises a lighting system that is configured to provide horticulture light having a controllable spectral power distribution.

[0026] The horticulture light is in particular provided to a basil plant. Such a basil plant can comprise a basil variety. The term "basil plant" can also refer to a plurality of basil plants.

[0027] In particular, such horticulture lighting device can further comprise a control system. Such control system can be configured to control the spectral power distribution of the horticulture light, among others. Therein, this can allow controlling the spectral power distribution over time. As mentioned above, a particular light recipe appears to be beneficial for increasing the cold tolerance of (basil plants). The control system can be comprised in the lighting system or can be configured external to the lighting system. In particular, the control system is functionally coupled to the lighting system. The present invention also provides the lighting system as such and / or the control system as such.

[0028] In embodiments, in the operational mode of the horticulture lighting device, the horticulture lighting device is configured to provide horticulture light according to an on-off time schedule, wherein the on-periods and off-periods are applied consecutively. Hence, the light recipe can comprise a series of consecutively performed on-periods and off-periods. In this way, the circadian rhythm can be mimicked. The set of on-periods and off-periods together can last 24 hours, but can also last shorter or longer. In particular, the shortest period can be 16 hours and the longest period can be 32 hours. Typically, the period can be about 24 hours. The 24 hours period can coincide with the day-night cycle that plants in a greenhouse experience. Especially in plant farms where plants are planted in a closed (daylight-free) environment that essentially only uses artificial light, the period can deviate from the day-night cycle. Also, generally speaking, the duration of the cycle is substantially the same throughout the growth of the plants. Hence, in embodiments, the control system can be configured to control the lighting system such that the lighting system provides horticulture light according to an on-off time schedule, wherein the on-periods and off-periods are applied consecutively.

[0029] In particular embodiments, the on-periods can last in the range of 12-20 hours, while the off-periods can last in the range of 4-12 hours. In particular, in embodiments, the on-periods last in the range of 14-19 hours and the off-periods last in the range of 5-10 hours. This can provide a good yield of basil plants in a reasonable time.

[0030] Typically, the spectral power distribution during the on-periods can be substantially the same throughout the on-period. However, in the present invention, at the end of the on-period, the contribution of far-red light can have a substantial contribution or increase. Hence, at the end of the on-period, there can be an end-of-day period, wherein the spectral power distribution of the horticulture light is different from the spectral power distribution of the horticulture light during the first part of the on-period.

[0031] Furthermore, the end-of-day period can last for an on-period of about 0.5-4 hours, which on-period can in total last in the range of 12-20 hours. Hence, the day-time period preceding the end-of-day period can last for about 8-19.5 hours. However particularly, in embodiments, the preceding day-time period can in particular last for at least about 10 hours, even more particularly for at least about 12 hours. Hence, in embodiments, the on-period comprises the end-of-day period at the end of the on-period, wherein the end-of-day period lasts in the range of 0.5-4 hours, for instance at least 1 hour. After the end-of-day period, the off-period can be started. Hence, in particular, the on-period ends with the termination of the end-of-day period. In other words, the off-period can start at the end of the end-of-day period.

[0032] As mentioned above, during the end-of-day period, the contribution of far-red light can be significantly higher than in the preceding part of the on-period. This appears to significantly increase the cold tolerance. Within the on-period preceding the end-of-day period, there can be some far-red light, but this is not necessarily the case. However, in particular, some far-red light is present in the substantially entire on-period, but with an (significantly) increased contribution in the end-of-day period. Furthermore, in general, some red light is comprised by the horticulture light in substantially the entire on-period, although this is not necessarily the case. However, in many embodiments herein, red and far-red horticulture light is present in the entire on-period. The increased cold tolerance is in particular obtained by the far-red contribution being relatively low in the part of the on-period preceding the end-of-day period, and the far-red contribution being relatively high during the end-of-day part of the on-period. In specific embodiments, during at least part of the on-period preceding the end-of-day period, the R / Fr ratio is chosen from the range of 4-20, the R / Fr ratio being defined as the ratio of the I 600-700nm of the red light and the I 700-800nm of the far-red light, and in at least part of the end-of-day period, the R / Fr ratio is chosen from the range of 0.1-4. In particular, in specific embodiments, during the (substantially) entire part of the on-period preceding the end-of-day period, the R / Fr ratio is chosen from the range of 4-20, the R / Fr ratio being defined as the ratio of the I 600-700nm of the red light and the I 700-800nm of the far-red light, and during the (substantially) entire part of the end-of-day period, the R / Fr ratio is chosen from the range of 0.1-4. In particular, the R / Fr ratio in the end-of-day period is at least 10% smaller, for instance at least 20% smaller, than the R / Fr ratio in the part of the on-period preceding the end-of-day period.

[0033] Hence, in embodiments, during the 8-19.5 hours of the on-period, the I 600-700nm of the red light and the I 700-800nmthe ratio of the far-red light to the horticulture light is in the range of 0.1-4. 600-700nm and the ratio of the red light to the horticulture light is in the range of 4-20, and during the last 0.5-4 hours of the end-of-day period, the I 700-800nm of far-red light.

[0034] In particular, in embodiments, the end-of-day period lasts at least in the range of 1 hour. Shorter periods, in particular shorter than about 0.5 hour, can have too little effect on cold tolerance. When the end-of-day period lasts at least 1-3.5 hours, in particular 1-3 hours, for example at least about 1.5 hours, best results can be obtained in terms of cold tolerance and energy efficiency.

[0035] Thus, in embodiments, during the end-of-day period (EOD) at the end of the on-period, the relative contribution of the far-red light having a wavelength selected from the range of 700-800 nm to the horticulture light is greater than the relative contribution of the far-red light to the horticulture light in the on-period before the end-of-day period (EOD).

[0036] During the (entire) on-period, the horticulture light can comprise one or more of: the first horticulture light (comprising a wavelength selected from the range of 400-600 nm); the red light (comprising a wavelength selected from the range of 600-700 nm); and the far-red light (comprising a wavelength selected from the range of 700-800 nm). In embodiments, during the end-of-day period, the horticulture light can essentially consist of the far-red light. In alternative embodiments, during the end-of-day period, the horticulture light can not only comprise the far-red light, but also one or more of the first horticulture light and the red light, in particular can comprise at least the red light, even more in particular can comprise the first horticulture light and the red light. For example, in embodiments, the first group of one or more light sources is configured to provide the first horticulture light and the red light (and optionally to provide some far-red light), and the second group of one or more light sources is configured to provide the far-red light (and optionally to provide some red light). Thus, in particular embodiments, during a part of the end-of-day period, the first horticulture light, the red light and the far-red light are provided.

[0037] In specific embodiments, the horticulture light during at least part of the opening period preceding the end-of-day period comprises: 5-20% of photons in the 400-500 nm wavelength range; 0-30% of photons in the 500-600 nm wavelength range; 50-95% of photons in the 600-700 nm wavelength range; and 0-6% of photons in the 700-800 nm wavelength range, the various contributions of photons adding up to no more than 100%. Alternatively or additionally, in embodiments, the horticulture light during at least part of the end-of-day period comprises: 0-10% of photons in the 400-500 nm wavelength range; 0-15% of photons in the 500-600 nm wavelength range; 0-80% of photons in the 600-700 nm wavelength range; and 20-100% of photons in the 700-800 nm wavelength range, the various contributions of photons adding up to no more than 100%.

[0038] Thus, in embodiments, during 8-19.5 hours of the opening period, horticulture light can be provided comprising: 5-20% of photons in the 400-500 nm wavelength range; 0-30% of photons in the 500-600 nm wavelength range; 50-95% of photons in the 600-700 nm wavelength range; and 0-6% of photons in the 700-800 nm wavelength range, the various contributions of photons adding up to no more than 100%, and during 0.5-4 hours at the end of the opening period, horticulture light can be provided comprising: 0-10% of photons in the 400-500 nm wavelength range; 0-15% of photons in the 500-600 nm wavelength range; 0-80% of photons in the 600-700 nm wavelength range; and 20-100% of photons in the 700-800 nm wavelength range, the various contributions of photons adding up to no more than 100%.

[0039] Therefore, the present invention (in one aspect) also specifically provides a horticultural lighting device, comprising: (i) a lighting system configured to provide horticultural light having a controllable spectral power distribution (to basil plants); and (ii) a control system configured to control the spectral power distribution of the horticultural light; wherein, in an operating mode of the horticultural lighting device, the horticultural lighting device is configured to provide horticultural light according to an on-off time schedule, wherein on-off periods and off-off periods are applied continuously, wherein: (i) the horticultural light comprises: one or more first horticultural lights, including wavelengths selected from the range of 400-600 nm; red light, including wavelengths selected from the range of 600-700 nm; and far-red light, including wavelengths selected from the range of 700-800 nm; (ii) the on-off period lasts for 12-20 hours, and the off-off period lasts for 4-12 hours, wherein the on-off period includes a daytime period located at the end of the on-off period, wherein the daytime period lasts for 0. (iii) wherein (a) during at least a portion of the on-time period before the end of the day, the horticultural light comprises: 5-20% of photons in the 400-500 nm wavelength range; 0-30% of photons in the 500-600 nm wavelength range; 50-95% of photons in the 600-700 nm wavelength range; and 0-6% of photons in the 700-800 nm wavelength range, wherein the total contribution of photons from different wavelength ranges does not exceed 100%, and (b) during at least a portion of the end of the day, the horticultural light comprises: 0-10% of photons in the 400-500 nm wavelength range; 0-15% of photons in the 500-600 nm wavelength range; 0-80% of photons in the 600-700 nm wavelength range; and 20-100% of photons in the 700-800 nm wavelength range, wherein the total contribution of photons from different wavelength ranges does not exceed 100%.

[0040] In a particular embodiment, the horticultural lighting device is configured to provide a light with a concentration of at least 50 µmol / m³ at a distance of at least 30 cm (and a maximum of 100 cm in a particular embodiment) from the lighting system during the on-time period. 2 Horticultural light with an average intensity in the range of / s. In a further specific embodiment, the horticultural lighting device is configured to provide horticultural light with an average intensity selected from 100-600 µmol / m² at a distance of at least 30 cm (and a maximum of 100 cm in a particular embodiment) from the lighting system during the on-time period. 2 The average intensity of horticultural light is in the range of / s. A distance of 30cm is typically the minimum distance between the lighting device producing the horticultural light and, for example, the substrate where the plants grow. This distance is measured specifically relative to the luminescent surface or exit window of such a lighting device that can emit horticultural light. In certain embodiments, it may be, for example, a lens of a light-emitting diode or a light-transmitting cover of the lighting device housing.

[0041] The best results in terms of yield and energy efficiency can be obtained in embodiments in which the horticulture lighting device is configured to provide horticulture light having an average intensity selected from the range of 150-450 µmol / m 2 / s at a distance of at least 30 cm (and in particular embodiments at a maximum of 100 centimeters) from the lighting system during the on-period.

[0042] During the off-period, there can be substantially no horticulture light at a distance of at least 30 cm from the lighting system, for example equal to or less than about 10 µmol / m 2 / s, even more particularly equal to or less than about 5 µmol / m 2 / s at a distance of at least 30 cm (and in particular embodiments at a maximum of 100 centimeters) from the lighting system. In particular, during the off-period, light having a wavelength selected from the range of 400-800 nm has an average intensity equal to or less than about 5 µmol / m 2 / s, for example equal to or less than about 5 µmol / m 2 / s at the sub-state level on or in which the plant is growing.

[0043] In embodiments, the spectral power distribution of the horticulture light is substantially constant during the on-period preceding the day-end period. In further embodiments, the spectral power of the horticulture light is substantially constant during the on-period preceding the day-end period. In embodiments, the spectral power distribution of the horticulture light is substantially constant during the day-end period. In further embodiments, the spectral power of the horticulture light is substantially constant during the day-end period.

[0044] When illuminating a plant with red and far-red light, the propagation length of far-red light through the canopy of the plant appears to generally be larger than that of red light. This can be because the leaves can better absorb red light than far-red light. This means that as the plant grows and the canopy size increases over time, the R / Fr ratio can decrease for the lower leaves of the plant, even under the same irradiation conditions. Therefore, in order to obtain the same R / Fr ratio on average for the whole plant, the R / Fr ratio can be set lower at an early stage of the growth period and larger at a later stage of the growth period, where the canopy is denser. Therefore, in embodiments of the operational mode, the contribution of far-red light to the horticulture light during the day-end period can be controlled in dependence on one or more of: (i) the growth time, growth stage or age of the (basil) plant(s); and (ii) the canopy density of the (basil) plant(s). Alternatively or additionally, in embodiments of the operational mode, the spectral power of the horticulture light during the day-end period can be controlled in dependence on one or more of: (i) the growth time, growth stage or age of the (basil) plant(s); and (ii) the canopy density of the (basil) plant(s).

[0045] One or more plants can define the canopy density. Different methods can be used to define the canopy density, such as the bare ground index, the canopy shadow index, etc. However, optical sensors can also be used to sense the canopy density, such as the reflection or transmission of light, etc. In particular, these embodiments can relate to the radiation from above the plants.

[0046] In yet other embodiments, the light sources configured to produce horticulture light can not only be provided above the plants, but also at a lower position, such as within the (future) canopy. Alternatively or additionally, the light sources can also be configured to produce horticulture light from below the plants, such as at a height of about the top of the substrate. Also in such embodiments, the R / Fr ratio and / or the spectral power can depend on the height of the respective light source. Hence, in embodiments, the lighting system comprises a first light producing device configured to produce at least part far-red light, wherein the first light producing device comprises a light emission surface from which the far-red light emanates during operation, and wherein in the operational mode the contribution of the far-red light to the horticulture light during the end-of-day period is controlled to a first height (hi) of the light emission surface of the horticulture light producing device above the substrate of the (basil) plant. Alternatively or additionally, in the operational mode the spectral power of the horticulture light of the horticulture light producing device during the end-of-day period is controlled to the first height (hi) of the light emission surface above the substrate of the (basil) plant.

[0047] In particular embodiments, the horticulture lighting device comprises a first light producing device configured to produce a first device light comprising far-red light, and a second light producing device configured to produce a second device light comprising one or more of the first horticulture light and red light. The term “first light producing device” can also refer to a plurality of (different) first light producing devices. Alternatively or additionally, the term “second light producing device” can also refer to a plurality of (different) second light producing devices.

[0048] In embodiments, the spectral power of the far-red light in the second device light is lower than the spectral power of the far-red light in the first device light, such as at least 5 times, in particular at least 10 times, the spectral power of the far-red light in the first device light is the spectral power of the far-red light in the second device light.

[0049] In embodiments, for the first device light at least 70%, even more particularly at least 80%, of the spectral power in the 400-800 nm wavelength range is in the 700-800 nm wavelength range, and for the second device light at least 70%, even more particularly at least 80%, of the spectral power in the 400-800 nm wavelength range is in the 400-700 nm wavelength range.

[0050] Thus, in embodiments, the first device light can substantially consist of far-red light, while the second device light can only include a relatively small far-red light contribution (or substantially no contribution).

[0051] Alternatively or additionally, in embodiments, the contribution of far-red light to the first device light is higher than the contribution of far-red light to the second device light, e.g. at least 5 times higher, e.g. in particular at least 10 times higher. Here, the term “contribution” can in particular refer to the number of photons (in the relevant spectral range). Further, in particular in embodiments during an opening period (D) before the end-of-day period (EOD), the contribution of the first device light to the horticulture light comprising the first device light and the second device light is less than 10%, and during at least part of the end-of-day period (EOD), the contribution of the first device light to the horticulture light comprising the first device light and the second device light is at least 20%.

[0052] In embodiments, each day-night cycle can include the end-of-day irradiation as described herein. However, it seems that also good results can be obtained when applying such EOD irradiation only during a part of the growing period of the (basil) plant. Thus, for example during the first weeks, the opening period does not have a specific EOD irradiation at the end of the opening period. The horticulture light can thus be as described herein with respect to the horticulture light in the period before the end-of-day period. However, during the last weeks of the growing period of the (basil) plant, the EOD irradiation as described herein is applied. Thus, in particular embodiments, the horticulture lighting device is configured (in an operational mode) to: (i) during the entire opening period, during a first part of the growing period t, apply horticulture light having an R / Fr ratio of at least 4, and (ii) during at least part of the end-of-day period (EOD), during a second part of the growing period t, apply horticulture light having an R / Fr ratio selected from the range of 0.1-4. This can be useful in a method of growing a basil plant having a growing period t in the range of at least three weeks. By such operational mode, the required cold resistance can be achieved, while energy consumption can be further reduced.

[0053] Also disclosed herein is a horticulture system comprising a horticulture lighting device as described above. The term “horticulture system” can in particular refer to a plant farm, a plant factory, a vertical farm, a city farm, and / or a climate cell. In embodiments, the horticulture system can comprise a climate cell.

[0054] In embodiments, the horticulture system and / or the horticulture lighting device can comprise a lighting apparatus, in particular wherein the lighting apparatus comprises a light source for providing the horticulture light. In further embodiments, the lighting apparatus can comprise an apparatus having an apparatus housing, wherein the light source is arranged (at least partially) in the housing. The term lighting apparatus can also refer to a plurality of (different) lighting apparatuses.

[0055] The term "light source" can in embodiments refer to a semiconductor light emitting device, such as a light emitting diode (LED), a resonant cavity light emitting diode (RCLED), a vertical cavity laser diode (VCSEL), an edge emitting laser, or the like. The term "light source" can also refer to an organic light emitting diode, such as a passive-matrix organic diode (PMOLED) or an active-matrix organic diode (AMOLED). In embodiments, the light source can comprise a solid state light source, such as an LED or a laser diode, in particular an LED. The term "LED" can also refer to a plurality of LEDs. Furthermore, the term "light source" can in embodiments also refer to a so-called chip-on-board (COB) light source. The term "COB" in particular refers to an LED chip in the form of a semiconductor chip which is neither encapsulated nor connected, but mounted directly on a substrate, such as a PCB. Thus, a plurality of semiconductor light sources can be configured on the same substrate. In embodiments, the light source can be a COB, wherein the COB is a multi-LED chip configured as a single lighting module. The term "light source" can also relate to a plurality of light sources, such as 2-2000 (solid state) light sources.

[0056] In embodiments, a light source configured to provide light having a wavelength selected from the sub-range of 400-800 nm is in particular a light source in which at least 50%, such as in particular at least 70%, such as at least 80%, such as even at least 90% of the power in the 400-800 nm spectral range is within the sub-range. In embodiments, the light source is a light source configured to generate light source light having a peak wavelength within the indicated sub-range, i.e. the maximum peak in the 400-800 nm range is within the sub-range.

[0057] Blue light can in particular be provided with a blue light source, such as in particular with a blue LED, although optionally a UV light source, such as in particular a UV LED, with a blue luminescent material can be chosen. Thus, in embodiments, the light source can comprise a blue light source.

[0058] Green light can in particular be provided with a green light source, such as in particular with a green LED, although optionally a blue light source, such as in particular a blue LED, with a green luminescent material, or a UV light source, such as in particular a UV LED, can be chosen. Thus, in embodiments, the light source can comprise a green light source.

[0059] Red light can in particular be provided with a red light source, such as in particular with a red LED, although optionally a UV light source, such as in particular a UV LED, with a red luminescent material, or a blue light source, such as in particular a blue LED, can be chosen. Similarly, this can apply to far-red and deep-red. Thus, in embodiments, the light source can comprise a red light source.

[0060] The white light can in particular be provided with a white light source, in particular a white LED, although optionally a UV light source, in particular a UV LED, or a blue light source, in particular a blue LED, with a suitable luminescent material can be chosen. As known to the person skilled in the art, a light source configured to produce white light is in particular a light source whose emitted light is white light. It in particular relates to light having a correlated color temperature (CCT) between about 2000-20000 K, in particular 2700-20000 K, in particular within about 15 SDCM (standard deviation of color matching) from the BBL (black body locus), in particular within about 10 SDCM from the BBL, in particular within about 5 SDCM from the BBL.

[0061] In particular, the different types of light provided herein are provided with light sources having peak wavelengths in the above indicated wavelength ranges corresponding to the different types of light.

[0062] In embodiments in which the lighting device comprises a plurality of light sources, two or more subsets of the plurality of light sources can be independently controllable in terms of light intensity. Further, the two or more subsets can provide light having different spectral distributions. In such embodiments, the intensity and spectral distribution of the horticulture light can be controllable. Hence, in embodiments, the two or more subsets can be configured to provide light having different spectral distributions.

[0063] Further, in particular embodiments, the lighting device can be configured to provide horticulture light having an average intensity selected from a range of at least 50 pmol / m2s, e.g. at least 100 pmol / m2s, at a distance of at least 30 cm, e.g. at least 100 cm, from the lighting arrangement. In particular, the lighting device can be configured to provide horticulture light having an average intensity at a distance of at least 30 cm from the lighting device. Further, the lighting device can be configured to provide horticulture light having an average intensity during a predetermined time period, e.g. a number of hours per day. 2 / s, e.g. in particular at least 100 pmol / m2s. 2 / s, e.g. in particular at least 100 pmol / m2s.

[0064] In embodiments, the horticulture system can comprise a (part of a) horticulture lighting arrangement. The horticulture system can in particular be configured to accommodate a plant. In particular, the horticulture system can comprise a support to support the plant. Hence, in embodiments, during operation, the plant can be arranged in the horticulture system. In particular, the term “horticulture system” can refer to a structure for accommodating a plant, in particular a structure in which the plant is grown under controlled conditions, more in particular a structure in which the plant substantially does not receive natural sunlight. Further, the horticulture system can be climate compliant, e.g. in case of a climate cell.

[0065] In a further embodiment, the climate unit may include plant supports and lighting equipment, and the control system may be configured inside or outside the climate unit.

[0066] Horticultural systems can be configured to grow food in multiple layers, thus making better use of available space compared to open-area or greenhouse cultivation. This means that natural sunlight will not reach all the plants in the horticultural system, and a significant portion of the light may need to come from artificial lighting. Therefore, the present invention particularly relates to horticultural systems in which plants receive essentially, especially essentially, only artificial light.

[0067] In use, a horticultural system may include plant supports with plants, or plant supports with seeds, or plant supports with seedlings, etc. Therefore, in use, a horticultural system may include plant supports with plants, or plant supports with seeds, or plant supports with seedlings, etc. The terms "support (or scaffold)" or "plant support (or scaffold)" may refer to one or more of a (granular) substrate, a hydroponic substrate (in the case of hydroponics), soil, wire (for wire crops), etc., which can be used to grow plants in, on, or along them.

[0068] In this embodiment, the gardening system and / or gardening lighting device may include a sensor.

[0069] In a further embodiment, the sensor can be configured to sense parameters, particularly plant-related parameters selected from the group consisting of: nutrients, leaf size, plant temperature, plant leaf temperature, plant root temperature, plant stem length, plant fruit size, etc.; or, particularly, environmental parameters selected from the group consisting of: temperature, humidity, gas composition (in a horticultural system, especially in a horticultural system), and natural sunlight intensity (where natural sunlight will be applied). In a further embodiment, the sensor may include a camera, such as a CCD camera. The term "sensor" may also refer to multiple (different) sensors. In particular, a horticultural system, especially a horticultural system, may include multiple (spatially separated) (light) sensors.

[0070] In a further embodiment, the sensor may be configured to sense one or more of the following: (i) the number and / or appearance and / or color of plant leaves, (ii) the area and / or color of plant canopy, and (iii) the number and / or appearance of plant flowers.

[0071] In this embodiment, the sensor may be configured to monitor plant-related parameters and provide relevant sensor signals (to the control system), particularly wherein the control system is configured to control the horticultural system based on the sensor signals. Specifically, the control system may control the spectral distribution and / or intensity of horticultural light based on the sensor signals.

[0072] In a further embodiment, the sensor can comprise a light sensor, which is configured to sense ambient light, and provide a related light sensor signal (to the control system), especially wherein the control system can be configured to (cause the lighting system to) provide horticulture light and / or supplemental light based on the light sensor signal. Hence, in embodiments, the horticulture light can be provided in dependence on the light sensor signal (or another sensor signal).

[0073] In embodiments, based on the feedback signal of the sensor, a (predetermined) spectral distribution and / or spectral power of the horticulture light can be provided.

[0074] Hence, in yet another aspect, the application provides a horticulture system (for basil plants), wherein the horticulture system comprises an indoor facility and a horticulture lighting device as defined herein. The horticulture lighting device can especially be configured to provide horticulture light (for growth of the basil plants) in the indoor facility, see also above. In a particular embodiment, the horticulture system comprises a plurality of first light generating devices or lighting devices as defined above, which in a particular embodiment are configured at different first heights (hi) of a light emitting surface above the growth substrate, wherein in the operational mode the contribution of far-red light to the horticulture light at the end-of-day period is controlled to the first heights (hi) of the light emitting surface above the growth substrate. Instead of the term "light emitting surface", also the term "final window" or "exit window" or "exit surface" can be applied (see also above). The second light emitting device can be configured above the plants, or in a particular embodiment also at a different height (above the substrate).

[0075] In embodiments, the horticulture system or the horticulture lighting device can comprise a control system. The control system can be configured to control (parts of) the horticulture system. In a further embodiment, the control system can be configured to control the lighting system, the lighting device and / or the lighting devices. In a further embodiment, the control system can be configured to control the sensor.

[0076] The conditions under which the (growing) plants are subjected to can generally be defined in a growth recipe. The control system can thus be configured to subject the plants to a growth recipe during operation. The growth recipe can comprise a light recipe, which can define a predetermined horticulture light setting, e.g. a horticulture light intensity. This can include that the light recipe further defines a predetermined horticulture light intensity as a function of time. Alternatively or additionally, the light recipe can define the predetermined horticulture light intensity as a function of a parameter, in particular a parameter determined with a sensor. In a further embodiment, the parameter can comprise a plant-related parameter selected from the group of: nutrient, leaf size, plant temperature, plant leaf temperature, plant root temperature, plant stem length, plant fruit size, etc. In a further embodiment, the parameter can comprise an environmental parameter selected from the group of: temperature, humidity, gas composition (in the horticulture system, in particular), and natural daylight intensity (in case natural daylight will also be applied). The "light recipe (or light recipe)" generally indicates a set of light parameters. The light recipe can be comprised by a recipe that also comprises other parameters, e.g. applied temperature, in particular at a plant part, e.g. at a plant leaf, or e.g. at a plant root.

[0077] In embodiments, the control system can be configured to control the spectral composition of the horticulture light in dependence on one or more of: (i) the number and / or appearance and / or color of the plant leaves; (ii) the area and / or color of the plant canopy; and (iii) the number and / or appearance of the plant flowers.

[0078] In embodiments, the control system can be configured to control the horticulture lighting device as well as other aspects of the horticulture system. In particular, the control system can be configured to control one or more of: temperature, humidity, irrigation, nutrient supply, light intensity of the horticulture light, air conditions, wherein air conditions comprise one or more of: air temperature, air composition, air flow, etc. in the horticulture system. The control system can be configured to control one or more of these conditions at different locations in the device.

[0079] In embodiments, the control system can be configured to control the sensor. In embodiments, the control system can be configured to (cause the horticulture system to) perform a method of the application (see below). In a further aspect, the application can also provide such a lighting device or light generating device. In a further aspect, the application can also provide such a sensor. In a further aspect, the application can also provide such a horticulture lighting device.

[0080] In another aspect, the present application provides a method of providing horticulture light to a basil plant. This method can also be included in a method of cultivating a basil plant (or a basil variety). In particular, the method can be applied with the horticulture lighting device described herein and / or the horticulture system described herein. Therein, the method can comprise providing horticulture light to the basil plant according to an on-off time schedule during a control mode, wherein an on-period and an off-period are applied consecutively. As described above, in particular, the horticulture light comprises one or more first horticulture light comprising a wavelength selected from the range of 400-600 nm; red light comprising a wavelength selected from the range of 600-700 nm; far-red light comprising a wavelength selected from the range of 700-800 nm. Further, as described above, in particular in embodiments, the on-period can last in the range of 12-20 hours, and in embodiments, the off-period can last in the range of 4-12 hours. Further, in particular, the on-period comprises an end-of-day period at the end of the on-period, before the start of the off-period.

[0081] In order to obtain (increased) cold tolerance of the basil plant, the R / Fr ratio is selected from the range of 4-20, the R / Fr ratio being defined as the ratio of the I 600-700nm and the I 700-800nm of the far-red light, during at least part of the on-period, before the end-of-day period. Thus, in particular, the present application provides in embodiments also a method of providing horticulture light to a basil plant, the method comprising providing horticulture light to the basil plant according to an on-off time schedule during a control mode, wherein an on-period and an off-period are applied consecutively, wherein: (i) the horticulture light comprises one or more first horticulture light comprising a wavelength selected from the range of 400-600 nm; red light comprising a wavelength selected from the range of 600-700 nm; far-red light comprising a wavelength selected from the range of 700-800 nm; (ii) the on-period lasts 12-20 hours, the off-period lasts 4-12 hours, wherein the on-period comprises an end-of-day period at the end of the on-period; (iii) wherein the R / Fr ratio is selected from the range of 4-20, the R / Fr ratio being defined as the ratio of the I 600-700nm and the I 700-800nm of the far-red light, during at least part of the on-period, before the end-of-day period, and the R / Fr ratio is selected from the range of 0.1-4, during at least part of the end-of-day period, in particular during the entire end-of-day period, wherein the R / Fr ratio during the at least part of the on-period (D) is larger than the R / Fr ratio during the at least part of the end-of-day period (EOD).

[0082] In particular embodiments, the on-period can last in the range of 14-19 hours, and / or the off-period can last in the range of 5-10 hours. Further, especially in embodiments, the end-of-day period can last in the range of 1-3 hours.

[0083] In particular embodiments, during at least part of the end-of-day period, the horticulture light comprises red light and far-red light. Further, in embodiments, the end-of-day period lasts in the range of 0.5-4 hours. In particular embodiments, the basil plant can be a basil variety selected from the group consisting of Cinnamon, Dolly, Emily, and Lemon. Especially for these varieties, (significantly) increased cold tolerance is obtained using the method described herein.

[0084] In embodiments, the method can comprise providing the basil plant with horticulture light having an average intensity selected from the range of at least 50 pmol / m2s during the on-period (in operational mode). In further particular embodiments, the method can comprise providing the basil plant with horticulture light having an average intensity selected from the range of 100-600 pmol / m2s during the on-period (in operational mode). In particular embodiments, the method can comprise providing the basil plant with horticulture light having an average intensity selected from the range of 150-450 pmol / m2s during the on-period (in operational mode). These intensities are intensities received by the plant and can for example be approximated by the intensity at the location of the substrate on or in which the plant is grown. 2 2 2 / s range. In particular, in embodiments, the method can comprise providing the basil plant with horticulture light having an average intensity selected from the range of 150-450 pmol / m2s during the on-period (in operational mode). These intensities are intensities received by the plant and can for example be approximated by the intensity at the location of the substrate on or in which the plant is grown.

[0085] In particular embodiments, the horticulture light during at least part of the on-period preceding the end-of-day period can comprise: 5-20% of photons in the 400-500 nm wavelength range; 0-30% of photons in the 500-600 nm wavelength range; 50-95% of photons in the 600-700 nm wavelength range; and 0-6% of photons in the 700-800 nm wavelength range, the total contribution of photons in the different wavelength ranges not exceeding 100%. Alternatively or additionally, especially the horticulture light during at least part of the end-of-day period can comprise: 0-10% of photons in the 400-500 nm wavelength range; 0-15% of photons in the 500-600 nm wavelength range; 0-80% of photons in the 600-700 nm wavelength range; 20-100% of photons in the 700-800 nm wavelength range; the total contribution of photons in the different wavelength ranges not exceeding 100%.

[0086] ​​As indicated above, in embodiments the method can further comprise controlling the contribution of far-red light to the horticulture light during the end-of-day period (in operational mode) in dependence on one or more of: (i) the growth time, the growth stage or age of the plant or plants; and (ii) the canopy density (defined by the plant or plants). Alternatively or additionally, the method can further comprise controlling the contribution of far-red light to the horticulture light during the end-of-day period (in operational mode) in dependence on the height at which the horticulture light is generated above the substrate (on or in which the plants are grown) or above the canopy in which the plants are grown. Hence, in particular embodiments the method can further comprise controlling the contribution of far-red light to the horticulture light during the end-of-day period (in operational mode) in dependence on the position at which the far-red light is provided and relative to the canopy of the basil plant.

[0087] Further, as indicated above, the far-red light enriched light can be provided during the end-of-day period, or only during the end-of-day period of a part (in particular the last part) of the total growth period. Hence, in specific embodiments the method can comprise growing the basil plant over a range of growth periods t, wherein t is at least three weeks, and wherein the method further comprises: (i) during a first part of the growth period t, applying horticulture light having an R / Fr ratio of at least 4 during the entire on-period; and (ii) during a second part of the growth period t, applying horticulture light having an R / Fr ratio selected from the range of 0.1-4 during at least part of the end-of-day period (EOD).

[0088] In embodiments, the method can comprise providing supplemental horticulture light, e.g. far-red light, to the plant, wherein the supplemental horticulture light is provided such that a minimum level (and a maximum level) of light intensity of the supplemental wavelength range (e.g. far-red wavelength range) is provided to the plant within the on-period and the end-of-day period as indicated herein. This can also be denoted herein as a “supplemental control mode”. Such supplemental control mode is particularly useful for supplementing known methods wherein the on-off timing of the horticulture lighting device does not provide or hardly provides far-red light to the plant.

[0089] In embodiments, the method can comprise providing horticulture light to the plant, in particular during the control mode. In further embodiments, the horticulture light can have an average intensity (over the plant) > 50 µmol / m 2 / s, e.g. > 100 µmol / m 2 / s, more in particular e.g. > 150 µmol / m 2 / s, e.g. in particular selected from the range of 50-1000 µmol / m 2 / s, even more in particular selected from the range of 150-1000 µmol / m 2a range of 200-1000, in further embodiments the first horticulture light can have an average intensity selected from the range of 200-1000, in embodiments the intensity < 800 pmol / m 2 / s, for example < 600 pmol / m 2 / s, for example < 600 pmol / m 2 / s, for example < 600 pmol / m 2 / s, for example < 600 pmol / m

[0090] In particular, the indicated light intensity can be provided over a range of 10-20 hours per day of the on-period (light or day), followed by 4-14 hours per day of the off-period (dark or night).

[0091] The conditions under which the (growing) plant is subjected to can generally be defined in terms of growth and / or light recipe (see above). Hence, the method can comprise subjecting the plant to a growth and / or light recipe.

[0092] In embodiments, the method can comprise controlling the spectral composition of the horticulture light as a function of (i) the number and / or appearance and / or color of the leaves of the plant, (ii) the area and / or color of the canopy of the plant, and (iii) the number and / or appearance of the flowers of the plant.

[0093] Hence, in embodiments, the method can comprise sensing one or more of (i) the number and / or appearance and / or color of the leaves of the plant, (ii) the area and / or color of the canopy of the plant, and (iii) the number and / or appearance of the flowers of the plant.

[0094] In yet another aspect, the application also provides a computer program product which, when running on a computer, especially in a control system as described herein functionally coupled to or comprised by a horticulture lighting system, causes the horticulture lighting system to perform the method of the application.

[0095] Hence, the application further provides a computer program product which is capable of performing a method as defined herein, for example when loaded onto a computer which is functionally coupled to a horticulture lighting system. In yet another aspect, the application provides a record carrier (or data carrier, such as a USB stick, CD, DVD, etc.) storing the computer program product.

[0096] The percentages of photons referred to herein relate to the total number of photons in the 400-800 nm spectral range. Thus, for example, the phrase "n% of the photons of the horticulture light" and similar phrases mean that n / 100 is in the particular indicated sub-range, of all (horticulture light) photons having a wavelength selected from the range of 400-800 nm. This does not exclude that the horticulture light (for example as can be provided by the lighting device or light generating device described herein) also provides other radiation, for example UV radiation. However, for the invention described herein, the number of photons relates to the total number of photons in the 400-800 nm range. As indicated elsewhere, "substantially (or mostly)" can especially mean at least 90%, for example at least 95%.

[0097] The intensity (of the horticulture light), here indicated as PPFD, can be determined from photodiodes or directly measured with a photomultiplier. The area in the PPFD especially refers to the local light receiving (plant) area of the space in which the light source is arranged. In case of a multi-layer system, it is the area of the relevant layer that is included in the multi-layer configuration; the PPFD related to each layer can then be estimated separately (see also below). In an embodiment, the area can be a value that is manually fed to the control unit, or in an embodiment can be evaluated by the control unit (for example using a sensor). The area (m 2 ) in phrases such as "at least 150 µmol / m 2 / s" and similar phrases can especially refer to the area of the root growth medium surface. The term "root growth medium surface" can refer to the liquid level in a hydroponic application, or it can refer to the top layer of a substrate (for example soil). For example, it can refer to the "level of the table", i.e. the level on which the plants are arranged. In particular, the phrase "at least 150 µmol / m 2 / s" and similar phrases refer to the intensity that is received by the plants. Thus, any part of the plant (i.e. especially those parts that are at least above the substrate) that can receive light (in the horticulture system) can receive such a dose. For example, the number of photons received per square meter per second at the top of the plant and at the bottom of the plant (but still irradiated by light) can be measured. The dose can then be calculated. The dose received at the plant can be approximated to the dose received at the root growth medium surface. When the indicated intensity is received at the root growth medium surface or at the level of the table (in the absence of plants), the plants will also receive at least such intensity. In particular, the term "root growth medium surface" can refer to the horizontal plane (on average).

[0098] The term "mode" can also be denoted as "control mode". The system or device or apparatus (see also below) can perform an action in a "mode" or "operating mode" or "mode of operation" or "control mode". Likewise, in a method, an action or stage or step can be performed in a "mode" or "operating mode" or "mode of operation" or "control mode". This does not exclude that the system or apparatus or device can also be adapted to provide another control mode or a plurality of other control modes. Likewise, this does not exclude that one or more other modes can be performed before and / or after performing the mode. However, in embodiments, a control system (see also below) can be available which is adapted to provide at least the control mode. If other modes are available, the selection of these modes can be performed, inter alia, through a user interface, although other options, such as performing a mode depending on a sensor signal or a (time) scheme, are possible. The operating mode can also refer to a system, apparatus or device which can only be operated in a single operating mode (i.e. "on", without further adjustability) in embodiments.

[0099] The term "controlling" and similar terms refer at least to determining a behavior or supervising a functioning of an element (here: the horticulture system or one or more elements thereof). Hence, "controlling" and similar terms herein can for example refer to exerting a behavior (determining a behavior or supervising a functioning) of an element, such as measuring, displaying, actuating, opening, moving, changing a temperature, etc. Further, the term "controlling" and similar terms can also include monitoring. Hence, the term "controlling" and similar terms can include exerting a behavior of an element, as well as exerting a behavior of an element and monitoring the element. Controlling of an element can be done by a control system, which can also be denoted as "controller". The control system and the element can thus be at least temporarily or permanently functionally coupled. The element can comprise the control system. In embodiments, the control system and the element can not be physically coupled. Controlling can be done by wired and / or wireless control. The term "control system" can also refer to a plurality of different control systems, which are in particular functionally coupled, and wherein for example one control system can be a master control system and one or more other control systems can be slave control systems. The control system can comprise or can be functionally coupled to a user interface. Examples of user interface means include manual activation buttons, displays, touch screens, keypads, voice-activated input devices, audio output, indicators (e.g. lights), switches, knobs, modems and network cards, etc. In particular, the user interface means can be configured to allow a user to instruct the device or apparatus or system with which the user interface is functionally coupled or by which the user interface is functionally comprised. The user interface can in particular comprise manual activation buttons, touch screens, keypads, voice-activated input devices, switches, knobs, etc., and / or optionally modems and network cards, etc. The user interface can comprise a graphical user interface. The term "user interface" can also refer to a remote user interface, such as a remote control. The remote control can be a separate dedicated device. However, the remote control can also be an App-equipped device with which the control system is configured (at least). The user interface is in particular functionally coupled to the control system or can be comprised by the control system.

[0100] Essentially the same embodiments as described with respect to the method can also apply to the horticulture system, in particular to the lighting device. The horticulture system, in particular the lighting device, can in particular be used in the method described herein and / or applied in the horticulture lighting system described herein.

[0101] With the present application, the cold tolerance of e.g. harvested basil plants, in particular their leaves, can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0102] Embodiments will now be described, by way of example only, with reference to the following schematic drawings wherein corresponding reference symbols indicate corresponding parts, and in which: - Figure 1 shows a schematic overview of a horticulture system according to an embodiment; and - Figure 2 shows a schematic overview of a horticulture system according to an embodiment.

[0103] Figures 1A-1E Some embodiments and aspects are depicted schematically. These schematic figures are not necessarily drawn to scale.

[0104] Figures 2A-2B This illustrates the R:FR ratios for various crowns due to crown shading and factors depending on plant density. Figure 2A The left side explains the measurement method. Figure 2A The right side shows the R:FR ratio as a function of plant growth period for two different planting densities. Figure 2B A picture of a basil crown is shown.

[0105] Figures 3A-3C The experimental setup and test results for the basil lemon variety are shown.

[0106] Figure 4A and 4B The test results for the basil varieties Cinnamon and Dolly are shown separately.

[0107] Figure 5A and 5B The test results for the Piccolino basil variety are shown.

[0108] Figure 6 The results of tests on the basil variety Emily are shown. Detailed Implementation

[0109] Figure 1A An embodiment of a horticultural lighting device 1000 is schematically depicted. The device 1000 includes a lighting system 100 and a control system 300. The lighting system 100 is configured to provide horticultural light 101 to a plant 1 (e.g., basil plant 1), the horticultural light 101 having controllable spectral power and spectral power distribution. The control system 300 is configured to control the spectral power and the spectral power distribution of the horticultural light 101.

[0110] The garden lighting fixture 1000 includes one or more light generating devices. For example, the garden lighting fixture 1000 includes a first light generating device 110 and a second light generating device 120. The former is configured to generate a first device light 111, and the latter is configured to generate a second device light 121. The garden light 101 may include one or more of the first device light 111 and the second device light 121.

[0111] The garden lighting fixture 1000 can be specifically configured (in the operating mode of the garden lighting fixture 1000) to provide garden light 101 according to the arrangement of on-off periods (where on-off period D and off-off period N are applied continuously).

[0112] The horticulture light 101 comprises one or more first horticulture light 1011 comprising a wavelength selected from the range of 400-600 nm, red light 1012 comprising a wavelength selected from the range of 600-700 nm, far-red light 1013 comprising a wavelength selected from the range of 700-800 nm. As schematically depicted, in this embodiment, the first light generating device 110 is configured to generate first device light 111 comprising far-red light 1013, and the second light generating device 120 is configured to generate second device light 121 comprising one or more first horticulture light 1011 and red light 1012. Other embodiments can also be possible. For example, the first device light 111 can also comprise (some) red light 1012, and the second device light 121 can also comprise (some) far-red light 1013.

[0113] In embodiments, the on-period D can last in the range of 12-20 hours. In embodiments, the off-period N can last in the range of 4-12 hours. In particular, the on-period D comprises an end-of-day period EOD at the on-period D end. This end-of-day period EOD lasts in embodiments in the range of 0.5-4 hours. Further, during at least part of the on-period D preceding the end-of-day period EOD, the R / Fr ratio, defined as the ratio of the I 600-700nm of the red light 1012 and the I 700-800nm of the far-red light 1013, can in particular be selected from the range of 4-20. Further, in embodiments, during at least part of the end-of-day period EOD, the R / Fr ratio can be selected from the range of 0.1-4. In particular, in embodiments, the end-of-day period EOD lasts in the range of at least 1 hour.

[0114] Hence, in particular embodiments, during the on-period D preceding the end-of-day period EOD, the contribution of the first device light 111 to the horticulture light 101 (comprising one or more of the first device light 111 and the second device light 121) can be less than 10%, and during at least part of the end-of-day period EOD, the contribution of the first device light 111 to the horticulture light 101 (comprising one or more of the first device light 111 and the second device light 121) can be at least 20%.

[0115] As mentioned above, the fact that far-red light is present during EOD does not exclude that also other types of light are present, for example red light. Likewise, the fact that one or more first horticulture light and red light (possibly together PAR light) are present during the on-period part preceding the EOD period, does not exclude the presence of other types of light, like far-red light. Hence, in embodiments of the part of the end-of-day period EOD, the first horticulture light 1011, the red light 1012 and the far-red light 1013 are provided.

[0116] The reference h1 denotes a height above the substrate 20 (or average substrate surface, e.g. water, soil, etc.). This height or distance is measured from the light emitting surface 115 or exit surface of the light generating device. This distance is denoted with reference d for the light generating device 110, 120 configured above the plant 1 at the same height h1.

[0117] Figure 1A An embodiment of a horticulture system 2000 is also schematically depicted, which is in particular for plants, e.g. more in particular for basil plants 1. The horticulture system 2000 comprises among others an indoor facility 2100. Further, the horticulture system 2000 comprises a horticulture lighting device 1000 as defined herein. In embodiments, the horticulture lighting device 1000 can be in particular configured to provide horticulture light 101 in the indoor facility 2100, in particular for growth of the (basil) plants 1.

[0118] In embodiments, the horticulture system 2000 comprises a plurality of light generating devices 110 configured at different first heights h1 of the light emitting surface 115 (or exit surface) above the substrate 20; see e.g. Fig. 2. In embodiments, the horticulture system 2000 comprises a plurality of light generating devices 110 configured at different second heights h2 of the light emitting surface 115 (or exit surface) above the substrate 20; see e.g. Fig. 2. Figure 1A In embodiments, the horticulture system 2000 comprises a plurality of light generating devices 110 configured at different first heights h1 of the light emitting surface 115 (or exit surface) above the substrate 20; see e.g. Fig. 2. In embodiments, the horticulture system 2000 comprises a plurality of light generating devices 110 configured at different second heights h2 of the light emitting surface 115 (or exit surface) above the substrate 20; see e.g. Fig. 2.

[0119] In particular, the horticulture lighting device 1000 is configured to provide horticulture light 101 having an average intensity selected from a range of at least 50 pmol / m2s, in particular selected from a range of 100-600 pmol / m2s, at a distance d of at least 30 cm from the light generating devices 110, 120 of the lighting system 100 during the on-period D. 2 2 / s of at least 50 pmol / m2s, in particular selected from a range of 100-600 pmol / m2s, at a distance d of at least 30 cm from the light generating devices 110, 120 of the lighting system 100 during the on-period D.

[0120] ​Further, in embodiments, the horticulture light 101 during at least part of the on-period D preceding the end-of-day period EOD can comprise: 5-20% of photons in the 400-500 nm wavelength range; 0-30% of photons in the 500-600 nm wavelength range; 50-95% of photons in the 600-700 nm wavelength range; and 0-6% of photons in the 700-800 nm wavelength range, with the total contribution of photons from the different wavelength ranges not exceeding 100%. Further, in embodiments, the horticulture light 101 during at least part of the end-of-day period EOD can comprise: 0-10% of photons in the 400-500 nm wavelength range; 0-15% of photons in the 500-600 nm wavelength range; 0-80% of photons in the 600-700 nm wavelength range; 20-100% of photons in the 700-800 nm wavelength range, with the total contribution of photons from the different wavelength ranges not exceeding 100%.

[0121] As indicated above, in the operational mode, the contribution of the far-red light 1013 to the horticulture light 101 during the end-of-day period EOD is controlled to one or more of: the growth time, growth stage or age of the plant or plants 1; and the canopy density (defined by the plant or plants 1). One way of estimating the canopy density is for example shadow measurement.

[0122] Figures 1B-1C A non-limiting number of embodiments of a day-night horticulture lighting scheme is schematically depicted, wherein D indicates that horticulture light is provided (day), and N indicates that substantially no horticulture light is provided (night). The horticulture light 101 that is primarily used for growth can be indicated as growth light GL. This horticulture light 101 can comprise one or more first horticulture light 1011 comprising a wavelength selected from the 400-600 nm range; and red light 1012 comprising a wavelength selected from the 600-700 nm range. Optionally, however, see also Figure 1C , the growth light can comprise far-red light 1013 comprising a wavelength selected from the 700-800 nm range. Substantially during the last part of the day, (additional) far-red light 1013 can be provided. This can overlap in time with the part of the time during which growth light is provided (although this need not necessarily be the case). After the far-red EOD period, a night period N can start.

[0123] Thus, Figures 1B-1C An embodiment of a method of providing horticulture light to a basil plant is schematically depicted, wherein the method comprises: during a control mode, providing horticulture light to the basil plant 1, see Figure 1A) providing horticulture light 101, wherein the on-period D and the off-period N are applied consecutively. The horticulture light 101 comprises: one or more first horticulture light 1011 comprising a wavelength selected from the range of 400-600 nm; red light 1012 comprising a wavelength selected from the range of 600-700 nm; far-red light 1013 comprising a wavelength in the range of 700-800 nm. Further, the on-period D can last in the range of 12-20 hours, while the off-period N can last in the range of 4-12 hours, wherein the on-period D comprises an end-of-day period EOD at the end of the on-period D. Further, during at least a part of the on-period D preceding the end-of-day period, the R / Fr ratio is selected from the range of 4-20, the R / Fr ratio being defined as the ratio of the I 600-700nm 700-800nm of the red light 1012 and the Iof the far-red light 1013, and during at least a part of the end-of-day period EOD, the R / Fr ratio is selected from the range of 0.1-4. In particular, the end-of-day period EOD can last 0.5-4 hours.

[0124] As Figures 1B-1C schematically depicted, during a part of the end-of-day period EOD, (also) the first horticulture light 1011, the red light 1012 and the far-red light 1013 can be provided. Likewise, some far-red light 1013 can also be available during a part of the day preceding the EOD.

[0125] Figures 1B-1C Only a single cycle is depicted. Such a cycle can be repeated (consecutively) during one or more periods, in particular during multiple periods (see also Figure 1E ).

[0126] Figure 1D The spectral power distribution of the horticulture light 101 of one embodiment is schematically depicted. Of course, other spectral power distributions are fully possible as well. Here, by way of example, substantially all types of horticulture light mentioned herein are available, including the first horticulture light 1011 which can have a blue and / or green light intensity, in particular including at least the blue, red light 1012 which can have a red light intensity, and including the far-red light 1013 which can have a far-red light intensity. During the day, the spectral power distribution of the horticulture light can change significantly when entering the EOD period from a period preceding the EOD.

[0127] Whether or not the EOD light is used can also depend on the growth stage, growth time or age of the plant. This is further explained in Figure 1EAn embodiment of a method is schematically depicted. Here, an embodiment of a method is schematically depicted, the method comprising growing a basil plant over a range of a growth period t, wherein t can be at least three weeks in embodiments, and wherein the method can further comprise: applying horticulture light 101 with an R / Fr ratio of at least 4 during a first part of the growth period t throughout an opening period D (schematically, see the first three days D); and applying horticulture light 101 with an R / Fr ratio selected from the range of 0.1-4 during a second part of the growth period t at least part of an end-of-day period EOD (schematically, see the second three days D). The height of the bars and the width of the bars are not to scale, but are schematic only.

[0128] Basil is a culinary herb that can provide aroma. People use the aroma of fresh leaves in food to adjust the flavor. During storage, basil is susceptible to cold damage at temperatures below 12°C. Cold damage can be seen as black spots on the leaves, wilting and loss of aroma. The present invention relates, inter alia, to a method of optimizing the use of far-red light to induce cold tolerance in a basil plant during growth of the basil plant, with an optimal light sequence, thereby saving energy, and unwanted physiological changes in the plant due to unnecessary far-red light exposure are also achieved.

[0129] The application of short day light periods (< 15 hours) can sometimes also increase cold tolerance compared to long day periods (18 hours). However, long day light periods are most beneficial for the grower, as he makes the most beneficial use of the lighting system he has installed (in terms of time of use). On the other hand, the application of far-red light throughout the day can lead to overstretching of the basil (in this case of prolonged exposure to far-red), but it increases the cold tolerance of the basil.

[0130] When growing at high density to optimize growth and light use efficiency, natural shading of the plant canopy occurs, so at the end of the plant growth, the R:FR ratio is lower. Therefore, a dynamic dose of far-red light can take into account the natural R:FR changes due to the canopy to reduce the energy use of far-red light during growth. Camera or sensor assisted light control can directly adjust the light level (red or far-red) to maintain the R:FR dose on the leaves of the plant.

[0131] Tests were performed in other varieties, Cinnamon, Dolly, Emily and Lemon. These all showed an increase in cold tolerance, especially when a relatively long day period was applied, for example at least 14 hours, even more especially at least 16 hours. The Cinnamon variety seems to be very sensitive to far-red light.

[0132] Test evidence

[0133] Determination of R:FR range

[0134] Support is provided for the low R:FR ratio range of 0.1-4 as follows and based on the following considerations. It is well known that far-red wavelengths can signal to the plant that shade is present, which triggers specific behavior of the plant and leaves. When growing plants in a farm, the plant density (number of plants per unit area) can lead to the formation of shade in the canopy as the plants grow. Figure 2B The effect of canopy size on the formation of shade below the top of the canopy is illustrated. Figure 2B The left photo in Fig. 1 is taken at position C (camera position) as indicated on the left. Figure 2A The left photo in Fig. 1 is taken at position C (camera position) as indicated on the left. Figure 2B The right photo is taken at a position near the base, indicated as Figure 2A the lower position S (sensor position) on the left. When measuring the light transmission in the canopy, it is first noted that when you lower the sensing position into the crop (see Figure 2A the lower position S on the left), the photosynthetically active radiation light level (PAR light, covering wavelengths in the range of 400-700 nm) decreases significantly. This decrease is more pronounced and more abrupt with increasing plant density. The second thing to note is that the intensity of far-red light (in the range of 700-800 nm) decreases much less. This is because of the low leaf absorption and high leaf transmission for wavelengths above 700 nm. This means that the R:FR ratio perceived by the basil canopy (especially at the lower positions in the canopy) changes over time as the plant canopy grows. Figure 2A The right part of Fig. 1 shows the change in R:FR ratio measured at the bottom of the canopy as a function of plant growth for two different planting densities (the horizontal axis represents time in days of growth).

[0135] The current state-of-the-art horticulture lighting devices can contain a small amount of far-red light (5% to 7%), thus providing an R:FR ratio of 10 or higher. The inventors have seen that basil grown under these conditions is sensitive to cold. To significantly improve the cold tolerance, the inventors found that it is necessary to lower the R:FR ratio, i.e. to increase the amount of far-red. The natural occurring shade in the canopy during growth in fact creates an R:FR ratio of 6 or 4 for the lower leaves (see Figure 2AThe R:FR ratio (right side) depends specifically on planting density. It has been found that the lower leaves of harvested basil plants grown at high planting densities—those experiencing significant shade periods (where increased far-red light is present)—exhibit improved cold hardiness. Therefore, the inventors consider the amount of additional far-red light in horticultural light corresponding to an R:FR ratio of 4 as the minimum amount required to achieve a cold hardiness effect in basil. Therefore, for a significant impact on cold hardiness, the R:FR ratio should be below 4. Since most currently available far-red light sources, such as far-red LEDs, also have a portion of spectral power in the red portion of their spectrum (i.e., the tail of the far-red LED spectral distribution points towards the red wavelength), a small amount of red light is always provided by far-red LEDs. Therefore, the maximum amount of far-red light expressed as an R:FR ratio in horticultural light is 0.1, which is the minimum achievable R:FR ratio.

[0136] Effect of end-of-day far-red light on cold tolerance of basil variety Lemon in the field

[0137] Basil-leaf lemon was used in this experiment. Seeds were artificially sown in soil trays at a density of 1000 plants per square meter. Once sown, the seed trays were covered with plastic film to maintain 100% humidity and placed in the dark at 20°C to induce germination. Two days after sowing, seedlings were transferred to growth cells and germinated at 180 µmol / m². 2 Irradiate under horticultural light using red-blue LED spectrum (RB180) with a photoperiod of 18 hours. Maintain a temperature of 24°C and a relative humidity of 70%. Use a fixed ebb-flow system, irrigating every 24 hours. Remove the plastic film 7 days after sowing. Transplant the plants into 7*7 cm asbestos blocks 12 days after sowing, at a density of 100 plants per square meter.

[0138] The plant control group (also known as the DRW Fr group) was treated with 232 µmol / m 2 The control horticultural light, with a light intensity of 164 µmol / m² and a deep red + white + far red spectrum (DRW Fr 232 µmol: 11% blue, 18% green, 71% red, 7% far red), was applied during an 18-hour on-time period. The R:FR ratio of the control horticultural light was 10. One experimental group of plants (also known as the EOD Fr group) was illuminated using a dynamic EOD-Fr light formulation, which consisted of: the same horticultural light conditions as the control group during the first 17 hours of the on-time period; and an intensity of 164 µmol / m² during the three-hour end-of-day period. 2 An additional far-red light of / s is provided, with the three-hour end-of-day period overlapping the DRW Fr of the first 17 hours of the opening period by one hour. The additional far-red light makes the R:Fr ratio 1, and then far-red allocation is only carried out in the 19th and 20th hours, making the R:Fr ratio 0.1. Figure 3AThe horticulture light recipe used in the control and EOD Fr group is illustrated. Sixteen days after transplanting and subjected to the light conditions described above, the plants were harvested and some of the harvest was kept in a storage room to measure shelf life and cold tolerance. It is noted that the total extra far-red light used in the test group relative to the control group amounts to 28 moles over the entire growth cycle of the basil.

[0139] The overall visual quality (OVQ) of the basil leaves of 10 samples in the control group and 10 samples in the test group was measured during storage. The concept of the overall visual quality (OVQ) measurement is described in the article "Quality Score System for Harvested Lettuce" by Kader et al., which can be found at http: / / ucce.ucdavis.edu / files / datastore / 234-417.pdf. The samples were stored at 4°C, 65% relative humidity. The overall visual quality was measured every two to three days and scored on a scale of 2-9. On this same scale, the customer acceptance threshold was set at a score of 6. When a sample was below this score, it was considered unsaleable, but the evaluation continued. The results are shown in Figure 3B (figure) and 3C (picture). Figure 3C It is shown that the plants grown under DRW Fr had already started to experience significant cold damage (leaf blackening) on day 5 of storage, while the plants treated with EOD Fr did not show cold damage.

[0140] Effect of end-of-day far-red light on cold tolerance of basil varieties Cinnamon and Dolly in the field

[0141] The test used the cultivars Cinnamon and Dolly. The light settings were the same as described above for the test on the cultivar Lemon. The overall visual quality (OVQ) results during storage are shown in Figure 4A (Cinnamon) and Figure 4B (Dolly).

[0142] Effect of end-of-day far-red light (where ratio R:Fr ~ 4)

[0143] The cultivar Piccolino was used for this test. These control plants were illuminated with horticulture light having a light intensity of 300 µmol / m 2 / s light intensity and a deep red + white + Fr light spectrum (DRW Fr: 11% blue, 18% green, 71% red, 7% far-red) for a 15 hour on-period. The R:Fr ratio of the control horticulture light was 10. The EOD-Fr light recipe of the test comprised the same horticulture light conditions as the control group for the first 14 hours of the on-period, and added 3 hours of horticulture light with an intensity of 50 µmol / m 2far-red light, with the DRW Fr before the 3-hour and end-of-day period overlapping for one hour at hour 15, making the R:Fr ratio 4, followed immediately by far-red light for only hours 16 and 17, making the R:Fr ratio 0.1.

[0144] Some plants of each treatment group (i.e. control and EOD-Fr group) were harvested at a growth temperature of 24°C, and others in each treatment group were harvested at a lower temperature of 16°C (although also grown at 24°C). It is known that the Piccolino variety is more temperature sensitive than other varieties of basil. The results show that the effect of harvest temperature on cold damage was mild, and a significant effect of EOD Fr application was observed in both cases. The results are shown in Figure 5A Figures 5A (harvest temperature 24°C) and 5B (harvest temperature 16°C).

[0145] Effect of applying far-red light before harvest on cold tolerance of basil variety Emily in the field

[0146] The cultivar Emily was grown in the same way as the lemon variety described above. However, after the plants were transplanted to their final growing environment, they were exposed to 150 pmol / m2s of far-red light for 2 hours per day for 3 weeks before harvest. 2 / s and deep red + white spectral DRW with 11% blue, 18% green, 71% red, 1% far-red. The control horticultural light had an R:Fr ratio of 70, and the applied horticultural light had a photoperiod of 16 hours per day (on period). Following the control group, which did not receive additional far-red light during growth, there were: a second group that received additional 180 pmol / m2s of far-red light for the entire on period for 3 weeks before harvest; and a third group that received additional 180 pmol / m2s of far-red light for the entire on period for only 1 week before harvest. The additional far-red light (on top of the DRW) resulted in an R:Fr ratio of 0.65. 2 / s and deep red + white spectral DRW with 11% blue, 18% green, 71% red, 1% far-red. The control horticultural light had an R:Fr ratio of 70, and the applied horticultural light had a photoperiod of 16 hours per day (on period). Following the control group, which did not receive additional far-red light during growth, there were: a second group that received additional 180 pmol / m2s of far-red light for the entire on period for 3 weeks before harvest; and a third group that received additional 180 pmol / m2s of far-red light for the entire on period for only 1 week before harvest. The additional far-red light (on top of the DRW) resulted in an R:Fr ratio of 0.65. 2 / s and deep red + white spectral DRW with 11% blue, 18% green, 71% red, 1% far-red. The control horticultural light had an R:Fr ratio of 70, and the applied horticultural light had a photoperiod of 16 hours per day (on period). Following the control group, which did not receive additional far-red light during growth, there were: a second group that received additional 180 pmol / m2s of far-red light for the entire on period for 3 weeks before harvest; and a third group that received additional 180 pmol / m2s of far-red light for the entire on period for only 1 week before harvest. The additional far-red light (on top of the DRW) resulted in an R:Fr ratio of 0.65. Figure 6 The results in Figure 5 show a significant increase in shelf life of up to 5 to 6 days (due to cold tolerance), which is a significant increase. This also shows that far-red light treatment for 1 week before harvest is almost as good as far-red treatment for 3 weeks before harvest. This shows that cold tolerance is built up especially in the last week before harvest. The total amount of additional far-red light applied in such a week is 70 moles. In comparison, the EOD far-red light experiment discussed above used 28 moles.

[0147] Therefore, using the EOD far-red light concept to increase cold tolerance in the week before harvest is more energy efficient than using far-red light "all day" because far-red LEDs are not very energy efficient. The duration of the end-of-day period is a compromise between the shortest duration to achieve an increase in cold tolerance and the longest duration to take into account the energy consumption (far-red LEDs have a relatively high energy consumption) and the longest duration to take into account the extension of the plant life by far-red light.

Claims

1. A garden lighting device (1000), comprising: (i) A lighting system (100) configured to provide horticultural light (101) with a controllable spectral power distribution; and (ii) a control system (300) configured to control the spectral power distribution of the horticultural light (101), wherein, in the operating mode of the horticultural lighting device (1000), the horticultural lighting device (1000) is configured to provide horticultural light (101) according to an on-off time schedule, wherein on-off periods (D) and off-off periods (N) are applied continuously, wherein: - Horticultural light (101) includes: one or more first horticultural lights (1011) including wavelengths selected from the range of 400-600 nm; red light (1012) including wavelengths selected from the range of 600-700 nm; and far-red light (1013) including wavelengths selected from the range of 700-800 nm; - The open period (D) lasts for 12-20 hours, and the closed period (N) lasts for 4-12 hours. The open period (D) includes the end of the day period (EOD) at the end of the open period (D), and the end of the day period (EOD) lasts for 0.5-4 hours. -During most of the opening period (D) preceding the end of day (EOD), the R / Fr ratio is selected from the range of 4-20, where the R / Fr ratio is defined in µmol / m 2 / s represents the intensity of red light (10¹²) of photons selected in the wavelength range of 600-700 nm, expressed in µmol / m 2 / s represents the ratio of the far-red (10¹³) light intensities of photons selected from the wavelength range of 700-800 nm, and during most of the end-of-day period (EOD), the R / Fr ratio is selected from the range of 0.1-4. -The R / Fr ratio is greater during most of the opening period (D) than during most of the closing period (EOD). -Among them, the contribution of far-red light (1013) to horticultural light (101) was significantly higher during most of the end-of-day (EOD) period than the contribution of far-red light (1013) to horticultural light (101) during most of the on-day (D) period. -The horticultural lighting device (1000) is configured to provide a light intensity of 100-600 µmol / m³ during the on-time (D) period. 2 The average intensity of horticultural light in the range of / s (101), and -Wherein, (a) during most of the opening period (D) before the end of day, the horticultural light (101) comprises: 5-20% of photons in the wavelength range of 400-500 nm; 0-30% of photons in the wavelength range of 500-600 nm; 50-95% of photons in the wavelength range of 600-700 nm; and 0-6% of photons in the wavelength range of 700-800 nm, and (b) during most of the end of day (EOD), the horticultural light (101) comprises: 0-10% of photons in the wavelength range of 400-500 nm; 0-15% of photons in the wavelength range of 500-600 nm; 0-80% of photons in the wavelength range of 600-700 nm; and 20-100% of photons in the wavelength range of 700-800 nm.

2. The garden lighting device (1000) according to claim 1, wherein, The horticultural lighting device (1000) is configured to provide horticultural light (101) at a distance of at least 30 cm from the lighting system (100) during the on-time (D).

3. The horticultural lighting device (1000) according to claim 1, wherein in the operating mode, the contribution of far-red light (1013) to the horticultural light (101) during the end-of-day period (EOD) is controlled according to one or more of the following: (i) the growth time of one or more plants (1), and (ii) the canopy density of one or more plants (1).

4. The garden lighting device (1000) according to any one of the preceding claims, wherein, The lighting system (100) includes a first light generating device (110) configured to generate at least a portion of the far-red light (1013), wherein the first light generating device (110) includes a light-emitting surface (115), and wherein, in an operating mode, the contribution of the far-red light (1013) to the horticultural light (101) during the end-of-day period (EOD) is controlled according to a first height (h1) of the light-emitting surface (115) above the substrate (20).

5. The garden lighting device (1000) according to any one of claims 1-3, comprising: A first light generating device (110) configured to generate a first device light (111) including far-red light (1013); and a second light generating device (120) configured to generate a second device light (121) including one or more first horticultural lights (1011) and red light (1012), wherein during an on-time period (D) prior to the end of day (EOD), the first device light (111) contributes less than 10% to one or more of the horticultural lights (101) including the first device light (111) and the second device light (121), and during at least the majority of the end of day (EOD), the first device light (111) contributes at least 20% to one or more of the horticultural lights (101) including the first device light (111) and the second device light (121).

6. The garden lighting device (1000) according to claim 1, wherein, The opening period (D) lasts for 14-19 hours, and the closing period (N) lasts for 5-10 hours, wherein the end-of-day period (EOD) lasts for 1-3 hours.

7. A gardening system (2000) comprising an indoor facility (2100) and a gardening lighting device (1000) according to claim 1, wherein, The horticultural lighting device (1000) is configured to provide horticultural light (101) in an indoor facility (2100).

8. The horticultural system (2000) according to claim 7, wherein, The horticultural system (2000) includes a plurality of first light generating devices (110) as defined in claim 4, the first light generating devices being configured at different first heights (h1) of the light-emitting surface (115) above the substrate (20), and wherein, in an operating mode, the contribution of far-red light (1013) to the horticultural light (101) during the end-of-day period (EOD) is controlled according to the first height (h1) of the light-emitting surface (115) above the substrate (20).

9. A method for providing horticultural light to basil plants (1), the method comprising: During the control mode, horticultural light (101) is provided to the basil plants (1) according to an on-off time schedule, wherein on-off periods (D) and off-off periods (N) are applied consecutively, wherein: - Horticultural light (101) includes: one or more first horticultural lights (1011) including wavelengths selected from the range of 400-600 nm; red light (1012) including wavelengths selected from the range of 600-700 nm; and far-red light (1013) including wavelengths selected from the range of 700-800 nm; - The open period (D) lasts for 12-20 hours, and the closed period (N) lasts for 4-12 hours. The open period (D) includes the end of the day period (EOD) at the end of the open period (D), and the end of the day period (EOD) lasts for 0.5-4 hours. -During most of the opening period (D) preceding the end of day (EOD), the R / Fr ratio is selected from the range of 4-20, where the R / Fr ratio is defined in µmol / m 2 / s represents the intensity of red light (10¹²) of photons selected in the wavelength range of 600-700 nm, expressed in µmol / m 2 / s represents the ratio of the far-red (10¹³) light intensities of photons selected from the wavelength range of 700-800 nm, and during most of the end-of-day period (EOD), the R / Fr ratio is selected from the range of 0.1-4. -The R / Fr ratio is greater during most of the opening period (D) than during most of the closing period (EOD). -Among them, the contribution of far-red light (1013) to horticultural light (101) was significantly higher during most of the end-of-day (EOD) period than the contribution of far-red light (1013) to horticultural light (101) during most of the on-day (D) period. -During the opening period (D), the basil plants (1) are supplied with a solution containing at least 50 µmol / m 2 The average intensity of horticultural light in the range of / s (101), and -Wherein, (a) during most of the opening period (D) before the end of day, the horticultural light (101) comprises: 5-20% of photons in the wavelength range of 400-500 nm; 0-30% of photons in the wavelength range of 500-600 nm; 50-95% of photons in the wavelength range of 600-700 nm; and 0-6% of photons in the wavelength range of 700-800 nm, and (b) during most of the end of day (EOD), the horticultural light (101) comprises: 0-10% of photons in the wavelength range of 400-500 nm; 0-15% of photons in the wavelength range of 500-600 nm; 0-80% of photons in the wavelength range of 600-700 nm; and 20-100% of photons in the wavelength range of 700-800 nm.

10. The method of claim 9, wherein the basil plant (1) is selected from the group consisting of cinnamon, dolly, emerald, and lemon.

11. The method of claim 9, comprising growing the basil plant (1) within a growth period t, wherein t is at least three weeks, and wherein the method further comprises: (i) During the first part of the growing season t, horticultural light (101) with an R / Fr ratio of at least 4 is applied throughout the opening period (D), and (ii) During the second part of the growing season t, horticultural light with an R / Fr ratio selected from the range of 0.1-4 is applied for at least most of the end-of-day period (EOD).

12. The method of claim 9 further comprises controlling the contribution of far-red light (1013) to horticultural light (101) during the end-of-day (EOD) period according to the location where far-red light (1013) is provided relative to the canopy of the basil plant (1).

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