Plant growing media and powders

Abstract

The objective is to provide a powder that achieves a high level of both aeration and water retention, and can be used as a growing medium for plants, etc. Furthermore, to provide a plant growing medium containing such a powder. [Solution] A plant cultivation medium having composite particles with a volume average particle size of 0.5 mm or more and 2.0 mm or less, wherein the composite particles are composite particles in which a part of particle B is embedded on the surface of particle A, or composite particles in which a part of particle A is embedded on the surface of particle B, wherein particle A is made of polyester, polystyrene, polyethylene, polypropylene, polylactic acid, or polyurethane, and particle B is made of cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite, and when the surface area of ​​the composite particle is ST and the area occupied by the surface of particle B on the surface of the composite particle is SB, SB / ST is 0.1 or more and 0.9 or less.

Description

[Technical Field]

[0001] This invention relates to a powder used as a growing medium for plants and the like, and to a growing medium for plants. [Background technology]

[0002] In recent years, traditional open-field cultivation has become difficult due to the effects of extreme weather and water shortages caused by global warming. Therefore, greenhouse horticulture, which allows for stable and planned crop production, is attracting attention. Within this context, there is a need to develop artificial soil particles that can retain water without impairing the aeration necessary for plant growth, thereby enabling healthy plant growth. Conventionally, methods for controlling aeration and water retention have involved controlling the pore size by adjusting the particle size to maintain aeration, and maintaining water retention through capillary action caused by the pore size. However, with the aforementioned control methods, aeration and water retention are in a trade-off relationship, making it difficult to achieve both simultaneously.

[0003] Therefore, Patent Document 1 proposes achieving both breathability and water retention by mixing a volume-reduced resin foam with hydrophilic inorganic foam particles. However, while the soil immediately after mixing can achieve both water retention and aeration, when used as a growing medium for plants, and during irrigation, the mixed state of the soil cannot be maintained, posing a challenge in achieving both aeration and water retention. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2000-8038 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention aims to solve the above problems. Specifically, it aims to provide a powder that can achieve a high level of both aeration and water retention and can be used as a growing medium for plants and the like. It also aims to provide a growing medium for plants containing such a powder. [Means for solving the problem]

[0006] As a result of diligent research to solve the above problems, the inventors of this invention have found the following powder, or a plant cultivation medium containing the powder. In other words, the present invention relates to a plant cultivation medium having composite particles having a volume average particle size of 0.5 mm or more and 2.0 mm or less, wherein the composite particles are composite particles in which a part of particle B is embedded on the surface of particle A, or composite particles in which a part of particle A is embedded on the surface of particle B, wherein particle A is formed of polyester, polystyrene, polyethylene, polypropylene, polylactic acid, or polyurethane, and particle B is formed of cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite, and when the surface area of ​​the composite particles is ST and the area occupied by the surface of particle B on the surface of the composite particles is SB, the ratio SB / ST is 0.10 or more and 0.90 or less. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a powder that can achieve a high level of both aeration and water retention and can be used as a growing medium for plants, and a growing medium for plants containing the powder. [Modes for carrying out the invention]

[0008] The present invention will be described in more detail below with reference to embodiments, but is not limited to these embodiments. Unless otherwise specified, the notations "XX or greater and YY or less" or "XX~YY" that represent a numerical range mean a numerical range that includes the lower and upper limits, which are the endpoints.

[0009] The inventors believe that the effects of this disclosure can be obtained by fulfilling the above conditions as follows. A plant cultivation medium having composite particles with a volume-average particle size of 0.5 mm or more and 2.0 mm or less, wherein the composite particles are composite particles in which a portion of particle B is embedded on the surface of particle A, or composite particles in which a portion of particle A is embedded on the surface of particle B, wherein particle A is made of polyester, polystyrene, polyethylene, polypropylene, polylactic acid, or polyurethane, and particle B is made of cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite, and when the surface area of ​​the composite particle is ST and the area occupied by the surface of particle B on the surface of the composite particle is SB, the SB / ST is between 0.10 and 0.90, which allows for more precise adjustment of the size of the pores formed by the composite particles and the hydrophilicity / hydrophobicity within the pores. As a result, it is believed that it is possible to achieve both air permeability and water retention by more precisely controlling the capillary action by the pores formed by the composite particles.

[0010] The plant cultivation medium of the present invention has composite particles having a volume average particle size of 0.5 mm or more and 2.0 mm or less, wherein the composite particles are composite particles in which a part of particle B is embedded on the surface of particle A (particle A is the mother particle and particle B is the child particle), or composite particles in which a part of particle A is embedded on the surface of particle B (particle B is the mother particle and particle A is the child particle). By using composite particles in which a portion of particle B is embedded on the surface of particle A, or vice versa, the size of the gaps formed between particles can be adjusted more precisely than with single particles. As a result, capillary action can be controlled more precisely, making it possible to achieve both aeration and water retention. Furthermore, when used as a growing medium for plants, and even when exposed to irrigation or wind and rain, the arrangement of particles A and B does not change, thus maintaining aeration and water retention.

[0011] Also, when the volume average particle diameter of the composite particles is less than 0.5 mm, the gaps formed by the composite particles become small, and sufficient air permeability cannot be obtained. When the volume average particle diameter of the composite particles is greater than 2.0 mm, the gaps between the particles become large, and the capillary action decreases, so sufficient water retention cannot be obtained. Therefore, the volume average particle diameter of the composite particles is preferably 0.5 mm or more and 2.0 mm or less, and more preferably 1.0 mm or more and 1.5 mm or less. The volume average particle diameter of the composite particles can be controlled by the major axis of particle A and the major axis of particle B.

[0012] The particle A of the present invention is formed of polyester, polystyrene, polyethylene, polypropylene, polylactic acid, or polyurethane, and the particle B is preferably formed of cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite. When particle A is formed of a material other than the polyester, polystyrene, polyethylene, polypropylene, polylactic acid, or polyurethane, the hydrophobicity of the composite particles decreases, and sufficient air permeability cannot be obtained. Also, when particle B is formed of a material other than the cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite, the hydrophilicity of the composite particles decreases, and sufficient water retention cannot be obtained.

[0013] Furthermore, when the surface area of the composite particles is ST and the area occupied by the surface of particle B on the surface of the composite particles is SB, SB / ST is 0.10 or more and 0.90 or less. When SB / ST is less than 0.1, the hydrophilicity in the gaps formed by the composite particles becomes too low, so the capillary action decreases, and sufficient water retention cannot be obtained. Also, when SB / ST is greater than 0.9, the hydrophilicity in the gaps becomes too high, so the capillary action is high and sufficient air permeability cannot be obtained. Therefore, SB / ST is preferably 0.10 or more and 0.90 or less, and more preferably 0.50 or more and 0.90 or less. SB / ST can be controlled by the addition amounts of particle A and particle B and the addition amount of salt during production described later.

[0014] The particle A of the present invention is preferably hydrophobic, and the particle B is preferably hydrophilic. Since the particle A is hydrophobic and the particle B is hydrophilic, the hydrophilicity and hydrophobicity in the gaps formed by the composite particles can be adjusted in more detail. As a result, the capillary action can be controlled more precisely, and thus both air permeability and water retention can be achieved.

[0015] The composite particles are preferably composite particles in which a part of the particle B is embedded in the surface of the particle A. When the composite particles are used as a medium for plant cultivation, since the contact points between the composite particles are the hydrophilic particle B, the water retention is improved due to the liquid cross-linking force between the particles, which is preferable.

[0016] The major axis of the particle A is preferably 0.5 mm or more and 1.5 mm or less, and the major axis of the particle B is preferably 0.1 mm or more and 0.7 mm or less. When the major axis of the particle A is 0.5 mm or more, it is preferable because it becomes easier to maintain a gap diameter that can provide sufficient air permeability in the gaps formed by the composite particles. Also, when the major axis of the particle A is 1.5 mm or less, it is preferable because it becomes easier to maintain a gap diameter that can provide sufficient water retention by capillary action in the gaps formed by the composite particles. When the major axis of the particle B is 0.1 mm or more, it is preferable because it becomes easier to maintain a gap diameter that can provide sufficient air permeability in the gaps formed by the composite particles. Also, when the major axis of the particle B is 0.7 mm or less, it is preferable because it becomes easier to maintain a gap diameter that can provide sufficient water retention by capillary action in the gaps formed by the composite particles.

[0017] As the material of the particle A used in the present invention, polyester, polystyrene, and polylactic acid are more preferable from the viewpoint of adjusting hydrophobicity. Also, as the particle B used in the present invention, cellulose and activated carbon are more preferable from the viewpoint of adjusting hydrophilicity.

[0018] Hereinafter, embodiments of the present invention will be described in detail. There are no particular limitations on the method for producing the composite particles of the present invention, but for example, the composite particles of the present invention can be produced by mixing particle A and a material forming particle B in a container, heating to fuse and fix particle B to the surface of particle A, and then sieving off excess particle B after cooling. To control the SB / ST, for example, when mixing particle A and the material forming particle B in a container using the method described above, salt can be added, and by heating to fuse and fix particle B and salt to the surface of particle A, and then sieving off excess particle B and salt after cooling, washing off the fixed salt with water, and drying. In this case, the SB / ST can be controlled by the amount of particle A, particle B and salt added.

[0019] The following describes the measurement methods for the composite particles, particle A, and particle B of the present invention. <Method for calculating the volume-averaged particle size of composite particles> The volume-average particle size of the composite particles of this invention is measured using an optical microscope with appropriately adjusted magnification. From the obtained image, 100 composite particles are arbitrarily selected, and their areas are calculated using an image processing device (Nireco Corporation, LUZEX AP). The equivalent diameter of a circle is calculated from the obtained area, and the volume-average particle size is calculated by calculation.

[0020] <Method for calculating the area SB occupied by the surface of particle B on the surface of a composite particle> The method for calculating the area SB occupied by particle B on the surface of a composite particle according to the present invention involves selecting 100 composite particles arbitrarily from images obtained using an optical microscope, similar to the method for calculating the volume-average particle size of composite particles, and performing the calculation using an image processing device (Nireco Corporation, LUZEX AP). The portion of the composite particle consisting of particle B is extracted by binarization image processing using the image processing device (Nireco Corporation, LUZEX AP). At that time, appropriate corrections are made by logical filtering and manual correction. It is first confirmed by FT-IR spectroscopy whether the composite particle consists of a portion of particle B embedded on the surface of particle A, or a portion of particle A embedded on the surface of particle B. On the image, it is possible to distinguish between a portion consisting of particle A and a portion consisting of particle B from the difference in color or shape. The area of ​​the composite particle obtained by the method for calculating the volume-average particle size of composite particles is taken as ST, and SB / ST is calculated.

[0021] <Method for identifying the materials forming particle A and particle B of a composite particle> The materials forming particles A and B in this invention are identified by measuring their FT-IR spectra. The FT-IR spectra are measured using the ATR method with a Fourier transform infrared spectrometer (Spectrum One: PerkinElmer) equipped with a universal ATR sampling accessory. The specific measurement procedure is as follows: The incident angle of infrared light (λ=5μm) is set to 45°. A Ge ATR crystal (refractive index=4.0) is used as the ATR crystal. Other conditions are as follows: Range Start: 4000cm² -1 End: 600cm -1 Duration Scan number:16 Resolution:4.00cm -1 Advanced: CO2 / H2O correction applied. (1) Place a Ge ATR crystal (refractive index = 4.0) into the apparatus. (2) Set Scan type to Background and Units to EGY, and measure the background. (3) Set Scan type to Sample and Units to A. (4) Weigh 0.01 g of the sample onto the ATR crystal. (5) Pressurize the sample with the pressure arm (Force Gauge is 90). (6) Measure the sample. (7) The obtained FT-IR spectrum is baseline-corrected using Automatic Correction. The materials forming particles A and B can be identified from the obtained FT-IR spectra. When identifying the materials forming particles A and B from a composite particle, only the portions of particle A and particle B should be sampled and measured. Alternatively, if the particles A and B constituting the composite particle are available, measurements may be performed using the obtained samples.

[0022] <Method for calculating the major axis of particle A and particle B> The measurement of the major axis of particle A and particle B in this invention is performed by selecting 100 particles arbitrarily from images obtained using an optical microscope, similar to the method for calculating the volume-average particle size of composite particles, and calculating the major axis of particle A and particle B of those particles using an image processing device (Nireco Corporation, LUZEX AP). [Examples]

[0023] Examples of the present invention relating to powders used as growing media for plants and other organisms, and to growing media for plants, will be described.

[0024] <Example of Particle 1 Production> • Bisphenol A ethylene oxide (2.2 molar adduct): 50.0 molar parts • Bisphenol A propylene oxide (2.2 molar adduct): 50.0 molar parts Terephthalic acid: 90.0 molar parts • Trimellitus anhydride: 10.0 moles 100 parts by mass of the monomer constituting the above polyester unit was mixed with 500 ppm of titanium tetrabutoxide in a 5-liter autoclave. A reflux condenser, moisture separator, N2 gas introduction tube, thermometer, and stirring device were attached to the autoclave, and the condensation polymerization reaction was carried out at 230°C while introducing N2 gas into the autoclave. The reaction time was adjusted to achieve the desired softening point. After the condensation polymerization reaction was complete, the material was cooled, pulverized, and then fed from the metering feeder into the hopper using a twin-screw extruder equipped with a hopper and a metering feeder for melt-kneading. The cylinder temperature of the extruder was set to 100°C. The molten mixture was extruded in a string-like form from a strand die, cooled in a cooling water bath, and then cut with a pelletizer to obtain particle 1. Particle 1 had an acid value of 30, a softening point Tm of 130°C, and a glass transition temperature Tg of 57°C.

[0025] <Example of manufacturing particles 2-6> In the example of producing particle 1, particles 2 to 6 were obtained in the same manner except that the cutting conditions in the pelletizer were changed and the major axis was altered.

[0026] <Example of Particle 7 Production> 0.62 parts by mass of sodium phosphate was added to 180 parts by mass of deionized water and dissolved and stirred. After heating to 65°C, a solution of 0.24 parts by mass of calcium chloride dissolved in 20 parts by mass of deionized water was added all at once. 0.20 parts by mass of 1% sodium dodecylbenzenesulfonate was added to the resulting mixture to prepare an aqueous medium containing the dispersion. To the above aqueous medium, 100.00 parts by mass of styrene, 1.00 part by mass of divinylbenzene, and 0.35 parts by mass of t-butyl peroxypivalate (25% toluene solution) were added, and the mixture was dissolved and dispersed under stirring to form a suspension. Next, the mixture was reacted at 70°C for 5 hours under stirring at 200 rpm. After the polymerization reaction was complete, the temperature inside the container was raised to 100°C and distillation was performed for 4 hours. After distillation, the mixture was cooled to 25°C, the contents were removed from the container, and the mixture was acid washed, dehydrated, and dried. Then, using a twin-screw extruder equipped with a hopper and a quantitative feeder, the mixture was fed from the quantitative feeder into the hopper and melt-kneaded. At this time, the cylinder temperature of the extruder was set to 140°C. The molten mixture was extruded in a string-like form from a strand die, cooled in a cooling water bath, and then cut with a pelletizer to obtain particle 7. The softening point Tm of the obtained particle 7 was 224°C, and the glass transition temperature Tg was 105°C.

[0027] <Examples of manufacturing particles 8-9> In the example of producing particle 7, particles 8 and 9 were obtained in the same manner except that the cutting conditions in the pelletizer were changed and the major axis was altered.

[0028] <Example of Particle 10 Production> L-lactide: 90.0 parts D-lactide: 10.0 parts Polyglycerin: 8.0 parts 100 parts by mass of the monomer constituting the above polylactic acid was mixed with 300 ppm of tin 2-ethylhexanoate in a 5-liter autoclave. A reflux condenser, moisture separator, N2 gas inlet tube, thermometer, and stirrer were attached to the autoclave, and a condensation polymerization reaction was carried out at 170°C while introducing N2 gas into the autoclave. Subsequently, the mixture was distilled under reduced pressure at 1 hPa for 1 hour to remove the solvent. After the distillation of unreacted material ceased, 5.0 parts of trimellitic anhydride were added, and the mixture was mixed at 180°C for 2 hours. The contents were then removed and cooled. Subsequently, a twin-screw extruder equipped with a hopper and a quantitative feeder was used to feed the mixture from the quantitative feeder into the hopper and melt-knead it. At this time, the cylinder temperature of the extruder was set to 100°C. The molten mixture was extruded in a string-like form from a strand die, cooled in a cooling water bath, and then cut with a pelletizer to obtain particles 10. The acid value of the obtained particles 10 was 20 mg KOH / g, the softening point Tm was 182°C, and the glass transition temperature Tg was 59°C.

[0029] <Example of Particle 13 Production> Particle 13 was obtained by grinding Viscopearl AH-2050L (manufactured by Rengo Co., Ltd.) in a coffee mill and then sieving it.

[0030] <Example of manufacturing particle 14-16> In the example of producing particle 13, particles 14 to 16 were obtained in the same manner except that the grinding conditions and sieving conditions in the coffee mill were changed and the major axis was changed.

[0031] <Example of Particle 17 Production> Particle 17 was obtained by grinding rice husk charcoal (manufactured by Togawa Heiwa Farm Co., Ltd.) in a coffee mill and then sieving it.

[0032] [Table 1]

[0033] Particles 11 and 12 are Viscoparl PD-3002 and Viscoparl PD-7002, respectively, and were used as is without grinding or pre-treatment.

[0034] <Example of manufacturing composite particle 1> The above-mentioned particle 1 was mixed with 210.0 parts by mass of particle 11 (Viscopearl PD-3002 (manufactured by Rengo Co., Ltd.)) in a container and heated at 100°C for 5 hours to fix the Viscopearl PD-3002 to the surface of particle 1. Then, the unfixed Viscopearl PD-3002 was sieved through a 1.0 mm mesh to obtain composite particle 1. The physical properties of composite particle 1 are shown in Table 3.

[0035] <Manufacturing examples of composite particles 2, 5-7, 11, 12, 14, 15, 18, and 19> Composite particles 2, 5-7, 11, 12, 14, 15, 18, and 19 were obtained in the same manner as in the production of composite particle 1, except that the particle type and the amount added were changed as shown in Table 2. The physical properties of composite particles 2, 5-7, 11, 12, 14, 15, 18, and 19 are shown in Table 3.

[0036] <Example of manufacturing composite particle 3> Composite particle 3 was obtained in the same manner as in the production of composite particle 1, except that particle 11 (Viscoparl PD-3002 (manufactured by Rengo Co., Ltd.)) was replaced with particle 12 (Viscoparl PD-7002 (manufactured by Rengo Co., Ltd.)). The physical properties of composite particle 3 are shown in Table 3.

[0037] <Example of manufacturing composite particle 4> Composite particle 1 (70.0 parts by mass) was mixed with 70.0 parts by mass of particle 11 (Viscopal PD-3002 (manufactured by Rengo Co., Ltd.)) and 450 parts by mass of sodium chloride (manufactured by Kishida Chemical Co., Ltd.) in a container and heated at 100°C for 5 hours. After that, the unattached particle 11 and sodium chloride were sieved through a 1.0 mm mesh, and then the attached sodium chloride was washed with water and dried to obtain composite particle 4. The physical properties of the obtained composite particle 4 are shown in Table 3.

[0038] <Manufacturing examples of composite particles 8, 9, and 20> Composite particles 8, 9, and 20 were obtained in the same manner as in the production of composite particle 4, except that the type of particles and the amount added were changed as shown in Table 2. The physical properties of composite particles 8, 9, and 20 are shown in Table 3.

[0039] <Examples of manufacturing composite particles 10 and 13> In the production of composite particle 1, composite particles 10 and 13 were obtained in the same manner except that the particle type was changed as shown in Table 2 and the heating temperature was changed to 150°C. The physical properties of the obtained composite particles 10 and 13 are shown in Table 3.

[0040] <Examples of manufacturing composite particles 16 and 17> In the production of composite particle 4, composite particles 16 and 17 were obtained in the same manner except that the particle type was changed as shown in Table 2 and the heating temperature was changed to 150°C. The physical properties of composite particles 16 and 17 are shown in Table 3.

[0041] [Table 2]

[0042] [Table 3]

[0043] The evaluation method used for the obtained particles is described below. The evaluation results are shown in Table 4.

[0044] <Water retention test> Measure 60 ml of the particles, immerse them in tap water for 24 hours to make them in a saturated water-containing state, and fill them into a separator with a diameter of 25 mm having a 100-mesh stainless steel screen. Using a vacuum pump with an arbitrarily set suction pressure and the suction pressure during suction being displayed, suction is performed at a suction pressure of 920 mbar for 2 minutes, then suction is performed at a suction pressure of 470 mbar for 1 minute, and the process of releasing for 20 seconds is repeated 5 times. Measure the weight of the obtained sample and set the wet weight to 470. Subsequently, perform vacuum drying at 40°C for 24 hours, measure the weight after drying, and set the dry weight to 470. Similarly, measure 60 ml of the particles, immerse them in tap water for 24 hours to make them in a saturated water-containing state, fill them into a separator with a diameter of 25 mm having a 100-mesh stainless steel screen, then suction is performed at a suction pressure of 920 mbar for 5 minutes, measure the weight of the obtained sample, and set the wet weight to 920. Subsequently, perform vacuum drying at 40°C for 24 hours, measure the weight after drying, and set the dry weight to 920. From the obtained wet weight 470, dry weight 470, wet weight 920, and dry weight 920, the water retention amount was calculated according to the following formula. Water retention amount = (wet weight 920 - dry weight 920) - (wet weight 470 - dry weight 470) A: The water retention amount is 1.80 cm 3 or more B: The water retention amount is 1.50 cm 3 or more and less than 1.80 cm 3 less than C: The water retention amount is 1.00 cm 3 or more and less than 1.50 cm 3 less than D: The water retention amount is less than 1.00 cm 3 less than

[0045] <Air permeability test> In the above water retention test, measure the suction pressure when releasing after suction 5 times at 470 mbar, and set the suction pressure to 470. Calculate the air permeability using the following formula from the obtained suction pressure 470. Air permeability = flow area × (2 × suction pressure 470 × 100 / fluid density) 1 / 2 × 60 Flow area: (inner diameter of the bottom of the separator) 2 × 3.14 Fluid density: Fluid density of air = 1.15 A: Air permeability is 8.50 × 10 -1 m 3 ·min -1 That's all. B: Air permeability 8.00 × 10 -1 m 3 ·min -1 The above 8.50 x 10 -1 m 3 ·min -1 less than C: Airflow capacity 7.50 × 10 -1 m 3 ·min -1 The above 8.00 x 10 -1 m 3 ·min -1 less than D: Airflow capacity 7.50 × 10 -1 m 3 ·min -1 less than

[0046] [Examples 1-15] In Examples 1 to 15, the above evaluation was performed using composite particles 1 to 15, respectively. The evaluation results are shown in Table 4.

[0047] [Comparative Examples 1-5] In Comparative Examples 1 to 5, the above evaluation was performed using composite particles 16 to 20, respectively. The evaluation results are shown in Table 4.

[0048] [Table 4]

[0049] Examples 1 to 15 yielded favorable results in all evaluation items. On the other hand, Comparative Examples 1 to 5 showed inferior results compared to the examples in at least one of the above evaluation items. Based on the above results, the present invention provides a powder that can achieve a high level of both aeration and water retention and can be used as a growing medium for plants, and also provides a growing medium for plants containing the powder.

[0050] This embodiment includes the following configuration. [Configuration 1] A plant cultivation medium having composite particles with a volume-average particle size of 0.5 mm or more and 2.0 mm or less, The composite particle is a composite particle in which a part of particle B is embedded on the surface of particle A, or a composite particle in which a part of particle A is embedded on the surface of particle B. The aforementioned particle A is formed of polyester, polystyrene, polyethylene, polypropylene, polylactic acid, or polyurethane. The aforementioned particle B is formed from cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite. When the surface area of ​​the composite particle is ST, and the area occupied by the surface of particle B on the surface of the composite particle is SB, then SB / ST is 0.10 or more and 0.90 or less. A growing medium for plants characterized by the following features. [Configuration 2] The aforementioned particle A is hydrophilic, The aforementioned particle B is hydrophobic. The plant growing medium described in Composition 1. [Configuration 3] The plant cultivation medium according to configuration 1 or 2, wherein the composite particle is a composite particle in which a part of particle B is embedded on the surface of particle A. [Structure 4] The major axis of particle A is 0.5 mm or more and 1.5 mm or less. The major axis of particle B is 0.1 mm or more and 0.7 mm or less. A plant growing medium described in any one of items 1 to 3. [Composition 5] The aforementioned particle A is formed of polyester, polystyrene, or polylactic acid. The particle B is formed of cellulose or charcoal. Plant growing medium as described in any one of items 1 to 4. [Composition 6] A powder having composite particles with a volume-average particle size of 0.5 mm or more and 2.0 mm or less, The composite particle is a composite particle in which a part of particle B is embedded on the surface of particle A, or a composite particle in which a part of particle A is embedded on the surface of particle B. The aforementioned particle A is formed of polyester, polystyrene, polyethylene, polypropylene, polylactic acid, or polyurethane. The aforementioned particle B is formed from cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite. When the surface area of ​​the composite particle is ST, and the area occupied by the surface of particle B on the surface of the composite particle is SB, then SB / ST is 0.10 or more and 0.90 or less. A powder characterized by the following features. [Composition 7] The aforementioned particle A is hydrophilic, The aforementioned particle B is hydrophobic. The powder described in composition 6. [Structure 8] The powder according to configuration 6 or 7, wherein the composite particle is a composite particle in which a part of particle B is embedded on the surface of particle A. [Composition 9] The major axis of particle A is 0.5 mm or more and 1.5 mm or less. The major axis of particle B is 0.1 mm or more and 0.7 mm or less. The powder described in any one of items 6 to 8 of the composition. [Configuration 10] The aforementioned particle A is formed of polyester, polystyrene, or polylactic acid. The particle B is formed of cellulose or charcoal. The powder according to any one of claims 6 to 9.

Claims

1. A plant cultivation medium having composite particles with a volume-average particle size of 0.5 mm or more and 2.0 mm or less, The composite particle is a composite particle in which a part of particle B is embedded on the surface of particle A, or a composite particle in which a part of particle A is embedded on the surface of particle B. The particle A is formed of polyester, polystyrene, polyethylene, polypropylene, polylactic acid, or polyurethane. The aforementioned particle B is formed of cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite. When the surface area of ​​the composite particle is ST, and the area occupied by the surface of particle B on the surface of the composite particle is SB, then SB / ST is 0.10 or more and 0.90 or less. A growing medium for plants characterized by the following features.

2. The aforementioned particle A is hydrophilic, The aforementioned particle B is hydrophobic. The plant growing medium according to claim 1.

3. The plant growing medium according to claim 1, wherein the composite particle is a composite particle in which a part of particle B is embedded on the surface of particle A.

4. The major axis of particle A is 0.5 mm or more and 1.5 mm or less. The major axis of particle B is 0.1 mm or more and 0.7 mm or less. The plant growing medium according to claim 1.

5. The particle A is formed of polyester, polystyrene, or polylactic acid. The particle B is formed of cellulose or charcoal. A growing medium for plants according to any one of claims 1 to 4.

6. A powder having composite particles with a volume-average particle size of 0.5 mm or more and 2.0 mm or less, The composite particle is a composite particle in which a part of particle B is embedded on the surface of particle A, or a composite particle in which a part of particle A is embedded on the surface of particle B. The particle A is formed of polyester, polystyrene, polyethylene, polypropylene, polylactic acid, or polyurethane. The aforementioned particle B is formed of cellulose, charcoal, vermiculite, perlite, zeolite, or radiolite. When the surface area of ​​the composite particle is ST, and the area occupied by the surface of particle B on the surface of the composite particle is SB, then SB / ST is 0.10 or more and 0.90 or less. A powder characterized by the following features.

7. The aforementioned particle A is hydrophilic, The aforementioned particle B is hydrophobic. The powder according to claim 6.

8. The powder according to claim 6, wherein the composite particle is a composite particle in which a part of particle B is embedded on the surface of particle A.

9. The major axis of particle A is 0.5 mm or more and 1.5 mm or less. The major axis of particle B is 0.1 mm or more and 0.7 mm or less. The powder according to claim 6.

10. The particle A is formed of polyester, polystyrene, or polylactic acid. The particle B is formed of cellulose or charcoal. The powder according to any one of claims 6 to 9.

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