A compostable biofortified greenhouse plant growing medium

Abstract

Described herein is a growing medium designed to physical specifications for the specific plant(s) and / or crop(s) types(s), so as to provide air space for the plants which in turn allows for root development as well as water retention and release in a way beneficial to plant growth and development. These parameters are obtained by using compostable, renewable waste stream products and combining ingredients, managing and mixing particle sizes, using filter style wrapping on the blocks, as well as surfactants and binding agents, either alone or in combinations. In some embodiments, the growing medium comprises material derived from one or more of pulses, hemp, oat and flax. For example, the material may be one or more of pulse straw and hulls, for example, pea straw and hulls; hemp hurd and fibers; oat hulls; and flax fiber.

Description

[0001] A COMPOSTABLE BIOFORTIFIED GREENHOUSE PLANT GROWING MEDIUM

[0002] PRIOR APPLICATION INFORMATION

[0003] The instant application claims the benefit of US Provisional Patent Application 63 / 514,640, filed July 20, 2023 and entitled “A COMPOSTABLE BIOFORTIFIED GREENHOUSE GROWING MEDIUM”, the entire contents of which are incorporated herein by reference for all purposes.

[0004] BACKGROUND OF THE INVENTION

[0005] Currently, the horticultural and fruit and vegetable markets utilize peat moss and rock wool (spun molten rock) as growth mediums in greenhouse and hydroponic plant production, sometimes in combination with secondary products such as coconut coir and hemp fibres that are available.

[0006] Peat moss, the most common, is a mined material that is under environmental pressure as its harvest is detrimental to the bogs where peat is formed. Furthermore, while peat moss is theoretically a renewable resource, the natural process is very slow in practice.

[0007] Rock wool is also a non-renewable resource, in addition to being non-recyclable or compostable.

[0008] Coconut coir is available in a ground or chopped manner only, and as such requires a vessel to hold it in place.

[0009] Hemp coir is available but this material does not absorb and release water in a manner that is beneficial to plant germination and growth. Furthermore, the material rapidly decomposes in many growing systems.

[0010] All the above products are available only as single source in that none are blended, fortified or designed other than to physically manipulate their structure. Furthermore, all require the addition of nutrients and other additives through the irrigation water.

[0011] SUMMARY OF THE INVENTION According to an aspect of the invention, there is provided a plant growing medium comprising:

[0012] 0.5-5.0% (w / w) binder;

[0013] 10-84% (w / w) bulk material; and

[0014] 15-40% (w / w) fiber material.

[0015] According to another aspect of the invention, there is provided a plant growing medium comprising: a bulk density of 0.05-0.15 g / cm3; pore volume of 75-98%; particle size of 0.1 -10 mm; air content of 25-70%; easily available water of 40-90%; and a water holding capacity of 500-800 mL / L.

[0016] DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications mentioned hereunder are incorporated herein by reference.

[0018] Described herein is a growing medium designed to physical specifications for the specific plant(s) and / or crop(s) types(s), so as to provide air space for the plants which in turn allows for root development as well as water retention and release in a way beneficial to plant growth and development, as discussed herein.

[0019] According to an aspect of the invention, there is provided a plant growing medium or media comprising the following structural characteristics:

[0020] As used herein, “bulk density” refers to the mass of the material divided by the overall volume of the material.

[0021] As used herein, “pore volume” refers to the volume of the pores in the material. This is typically measured using the volume of water the material will hold when fully saturated divided by the overall volume of the material.

[0022] As used herein, “particle size” refers to the diameter of a particle of the material.

[0023] As used herein, “air content” refers to the difference in percentage by volume between the total pore space and the moisture content at a suction of 1 .0 kPa

[0024] As used herein, “easily available water” refers to water available for unhindered growth, defined as the % V / V released between suction forces of 1 .0 to 5.0 kPa over the total water absorbed by the sample.

[0025] As used herein, “water holding capacity” refers to the volume of water (mL) that will be absorbed by 1 L of the plant growing medium.

[0026] As discussed herein, these parameters are obtained by using compostable, renewable waste stream products and combining ingredients, managing and mixing particle sizes, using filter style wrapping on the plant growing medium blocks or other structures, as well as surfactants and binding agents, either alone or in combinations.

[0027] In some embodiments, the growing medium comprises binders, bulk material (formed or naturally granular particles), fiber material (fiber particles) and additives, such as for example but by no means limited to nutrients, biochar and buffers, as discussed below.

[0028] In some embodiments, the plant growing medium comprises:

[0029] 0.5-5.0% (w / w) binder; 10-84% (w / w) bulk material; and

[0030] 15-40% (w / w) fiber material.

[0031] In some embodiments, the plant growing medium described above has the physical characteristics as described above.

[0032] In yet other embodiments, the plant growing medium as described above has the physical characteristics described above and is composed of particles that range from 0.1 -10 mm in diameter.

[0033] In some embodiments, the plant growing medium as described above has the physical characteristics described above and is composed of particles that range from 0.1 -10 mm in diameter with over 60% of the material being less than 2 mm by weight.

[0034] In some embodiments, the plant growing medium as described above has the physical characteristics described above and is composed of particles that range from 0.1 -10 mm in diameter with over 60% of the material being less than 2 mm by weight and wherein the particles have a smooth, non stepped distribution curve.

[0035] In some embodiments, the plant growing medium comprises:

[0036] 0.5-5.0% (w / w) binder;

[0037] 10-84% (w / w) bulk material; and

[0038] 15-40% (w / w) fiber material, characterized in that the binder, bulk material and fiber material are composed of particles that range from 0.1 -10 mm in diameter and said plant growth material or an article formed therefrom has physical characteristics comprising: a bulk density of 0.05-0.15 g / cm3; pore volume of 75-98%; particle size of 0.1 -10 mm; air content of 25-70%; easily available water of 40-90%; and a water holding capacity of 500-800 mL / L.

[0039] In some embodiments, over 60% of the particles have a diameter of less than 2 mm (w / w). In some embodiments, the particles have a smooth, non stepped distribution curve.

[0040] In some embodiments, the growing medium comprises material derived from one or more of pulses, hemp, oat and flax. For example, the material may be one or more of pulse straw and hulls, for example, pea straw and hulls; hemp hurd and fibers; oat hulls; and flax fiber. In some embodiments, other waste products, including potato derived products such as potato starch, egg waste materials and bioplastics may be added, as discussed herein.

[0041] As will be appreciated by those of skill in the art, suitable binders include but are by no means limited to ground oat hulls, pea starch, corn starch, potato starch, lignin, molasses, organic acids such as humic acid, and corn syrup and suitable ethanol syrups.

[0042] As will be appreciated by one of skill in the art, suitable bulk material includes but is by no means limited to typha, peas (bulk and / or chopped in pods), peat, compost, hemp hurd, biochar, corn, corn distiller grains, potato, canola, wheat, distilled wheat from ethanol production, malting by-products such as those from barley, wheat and corn, bark, and paper and / or wood production by-products.

[0043] As will be appreciated by one of skill in the art, suitable fibers include but are by no means limited to coconut coir, straw (for example, pea, wheat, barley, oats and the like), cereal chaff, hemp, and flax, although other suitable fibers will be apparent to those of skill in the art and are within the scope of the invention.

[0044] In some embodiments of the invention, the growing medium is molded into a shape that is suitable for holding a plant, for example, the type of plant that is typically grown in a greenhouse. Examples of suitable plants will be readily apparent to those of skill in the art, but may include for example but by no means limited to tomatoes, lettuce, peppers, cucumbers, berries (for example, strawberries), and marijuana (cannabis) plants.

[0045] In some embodiments, a wrap material may be placed around the molded shape to hold the structure together. The wrap may be made of any suitable material, for example a material that is biodegradable and / or compostable as discussed herein. Furthermore, suitable examples include but are by no means limited to a cellulose wrap, wrap made of a bioplastics material, polylactic acid (PLA), paper and / or wood products (for example, cardboard, filter paper and the like) straw pulp products and densified and matted material also used within the molded product, for example, hemp fiber, flax fiber, coconut coir and the like, as discussed herein.

[0046] In some embodiments, the growing medium is packaged for sale as a loose fill product, as discussed below.

[0047] In other embodiments, the growing medium is shaped, formed or molded into a specific shape, for example, a pot or planter or pod or block of various sizes, including for example long strips (for example 6” wide, 4” high, 72” long) which are what is common in the industry.

[0048] Provided below are exemplary examples of suitable formulae for producing the growth medium of the invention. It is of note that in these examples, ground oat hulls and pea starch for example may be substituted for one another. Furthermore, other substitutions of like material, for example, one binder for another, or one fiber for another, or one bulk material for another, may be made, as discussed herein.

[0049] Recipe #1 - 1 % lignin, 94% hemp, 5% flax;

[0050] Recipe #2 - 5% pea starch, 65% hemp, 30% pea straw;

[0051] Recipe #3 - 5% ground oat hulls, 65% hemp fiber, 30% pea straw;

[0052] Recipe #4 - 5% ground oat hulls, 20% typha, 75% hemp fiber;

[0053] Recipe #5 - 5% pea starch, 70% peat, 25% hemp;

[0054] Recipe #6 - 5% pea starch, 65% peat, 15% typha, 15% hemp;

[0055] Recipe #7 - 5% pea starch, 35% peat, 10% typha, 20% hemp hurd, 30% hemp fiber;

[0056] Recipe #8 - 5% ground oat hulls, 5% compost, 10% pea pods; 60% hemp hurd, 20% hemp;

[0057] Recipe #9 - 1 % lignin, 34% peat, 40% hemp hurd, 25% pea straw; and Recipe #10 - 5% lignin, 10% peat, 60% hemp hurd, 20% hemp, 5% pea straw. In some embodiments of the invention, the growing medium comprises: (a) 3-10% ground oat hulls or pea starch, 50-70% hemp fiber, 20-40% pea straw, 0-5% plant-tailored nutrients;

[0058] (b) 3-10% ground oat hulls or pea starch, 10-20% typha, 75-85% hemp fiber, 0-5% plant-tailored nutrients; or

[0059] (c) 3-10% pea starch or ground oat hulls, 35-45% peat, 10-20% typha, 15- 25% hemp hurd, 25-35% hemp fiber, 0-5% plant-tailored nutrients.

[0060] These recipe examples are shown in Table 2, wherein WABD represents the weighted average bulk density, which is the sum of the products of the individual ingredients’ bulk density and their inclusion percentage. As will be appreciated by those of skill in the art, the bulk density is important to make sure the other parameters are able to fall within their specified ranges. For example, if the block is too dense it will be hard to get enough air space and absorption capabilities into the space that is available.

[0061] In some embodiments, the organic matter is sterilized so that no diseases or insects are introduced into the growth medium, as discussed herein. Specifically, as is known by those of skill in the art, the introduction of soil into growing areas is often the precursor to disease issues.

[0062] In some embodiments, growth promoting additives such as for example but by no means limited to nutrients, biochar, organic acids, and other additives such as pH adjusters in specific ratios are added to the growing medium to assist in rapid, healthy growth of the plants and to provide enhanced nutritional content for the plant products. These products may vary in composition based on crop type and may be specific to each crop. However, the requirements of different plants and / or crop types for optimum growth are known in the art and as such, such modifications are held to be within the scope of the invention.

[0063] For example, for leafy green crops, the addition of magnesium and calcium is important, whereas for flowering crops, phosphate plays a larger role.

[0064] For crops in early stages of growth, zinc is a major factor.

[0065] There are also nutrient ratios to be considered, for instance, tomatoes and peppers use a lower nitrogen amount, in the range of 3-1 -6 (NPK) compared to leafy greens and grasses which use 6-1 -3 NPK, while spinach utilizes more iron (deep green leaves).

[0066] As will be understood by those of skill in the art, the plant growing medium of the invention provides a soil-like medium which comprises the beneficial components of soils, and incorporates growth promoting additives such as for example nutrients, organic acids, and other bio actives such as for example, biochar, seaweed extracts and chitin among others, as well as enzymes and pH modifiers while excluding or reducing problematic components that (for instance) inhibit the uptake of nutrients or cause diseases, as discussed herein.

[0067] For example, biochar (a carbon additive) acts as a plant health enhancer and / or an ingredient to enhance nutrient utilization. Specifically, once the growing medium is either (trans) planted or composted, the biochar will act to sequester carbon in the soil or compost, resulting in additional “after use” benefits of the plant growing medium in these embodiments.

[0068] These additives promote enhanced nutrient uptake while also providing a natural source of balanced nutrition. This enhances plant growth which in turn also promotes better plant health -as a healthy, more robust plant is better equipped to resist or recue the incidence of disease. These additives provide a healthy soil structure.

[0069] As discussed above, the growing medium can be formed or molded into any suitable shape for plant growth. Suitable shapes include but are by no means limited to cubes, rectangular cubes and cylinders, as discussed above.

[0070] Furthermore, as will be apparent to those of skill in the art, these products may be produced by placing the growing medium into a suitable mold at a suitable temperature and / or pressure for a suitable period of time for the molded product to be formed.

[0071] In some embodiments, instead of a formed shape, the growing medium is packaged and sold as a loose fill product. In these embodiments, each particle of the loose fill comprises a mix of all of the ingredients so that the plant growing medium is mixed in the correct ratio. Specifically, in these embodiments, the loose fill product includes binder and takes on water as the formed product does. Furthermore, the same kinds of plants, that is, virtually any plant, can be grown in the loose fill growing medium.

[0072] As will be appreciated by those of skill in the art, the bulk materials will settle at the bottom of the block if added directly to the mix. However, this can be overcome by binding the bulk materials to the fibers.

[0073] For example, this can be overcome by using the fiber portion effectively as a scaffold to aid in holding the larger particle size material.

[0074] Alternatively, longer fiber particles can be woven into a scaffold.

[0075] In other embodiments, the bulk material is mixed with the binder prior to adding the fibers so that the bulk material is primed to attach to the fibers.

[0076] In yet other embodiments, the growing medium can be formed by spinning and layering materials alternating between fibrous and bulk materials, and using binder throughout for adhesion.

[0077] Once the bulk material is bound to the fibers, for example, in a layer or as otherwise described above, the material can be pelleted and / or subjected to densification. For loose fill, these densified shapes are then broken down into smaller pieces. For molded products, in some embodiments, the densified material may be (partially) rehydrated prior to molding.

[0078] Alternatively, the growing medium may be prepared such that separate block components are provided to the user as separate items, for example, fiber / bulk materials / binder, wrap and container so that the user assembles components prior to use.

[0079] In other embodiments, bulk material may be pre-processed (e.g., crumbled, pelleted, extruded and / or blended) to modify particle size and ensure homogeneous mixing of component materials

[0080] Alternatively, a mix of the raw ingredients can be granulated and / or pelletized into homogenous particles which are then reformed into a densified shape or kept as loose fill. Currently, most mediums carry the pH of the underlying components of the raw material they are derived from and the adjustment of the pH is primarily made through additives to the water. This is typically done to compensate for pH issues that may result in the tie up of nutrients into unavailable plant forms which may be related to the nature of the soil and / or the other types of organic components used. .

[0081] However, by incorporating growth promoting additives as described above into the medium itself, these materials are present at the optimum pH for nutrient availability. This also lessens the nutrient tie up in solution itself (where the minerals are most active) by moving the primary source of the minerals into the medium which also reduces or eliminates the need to treat the water. For example, the materials may be treated such that, in use, the growing medium has a pH between 5-8.

[0082] As discussed above, the additives are added in prescribed amounts to provide for optimum growth and production in the respective plant during their use cycle but such that the additives are drawn down in a manner so that, at the end of this cycle, the additives will not have a discernible negative effect on water sources or composting areas.

[0083] In this manner, a balance between sufficient supply of the essentials for optimum plant growth and a planned soil depletion is created that results in the maximum efficiency in the usage of the additives.

[0084] Unique Attributes

[0085] 1 ) A mix of base materials (bulk, fiber and binder) from multiple sources

[0086] As discussed herein, the base materials are primarily hydroscopic and hydrophobic. That is, these materials are selected so that water will be absorbed and retained for a period of time at a level that is beneficial to plant growth but that also releases the moisture in over a period of time such that the plant does not become waterlogged, and so that the medium does not begin to degrade (rot).

[0087] Surprisingly, the moisture release that we believed was from the structure of the medium takes place almost exclusively through plant uptake. As such, the air to water ratio is critical for the growing medium as this place a limit on the saturation level of the growth medium. Specifically, over watering from decreased air:water ratios would result in a degradation of the medium and plant death from drowning, whereas drying from an increased air:water ratio would result in early plant death or at minimum poor plant growth from a lack of moisture.

[0088] Results of a water retention study are provided in Table 1 , which shows the growing medium as capable of having a water:air ratio of at least 6.9.

[0089] Alternatively, this may be expressed in a weight-to-weight context rather than air to water ratio. Essentially, the results of the experiment shown in Table 1 show that the medium can hold up to 6.9-7.2 times its dry weight in or of water once water is added, and without plant uptake retains this amount of water (moisture) for at least 24 hours. As will be appreciated by one of skill in the art, in use, the growing medium would be supplied with water, that is, have the water supply replenished, for example, through a hydroponic system.

[0090] In some embodiments of the invention, the growing medium absorbs 5-9 times or 5-8 times or 5-7 times its dry weight in water. Specifically, more water allows for more nutrient access in a hydroponic system. For example, peat moss has a total pore space of up to 97% (although 82% - 85% is typical) and a high water-holding capacity; holding 60% to 68% of its volume in water.

[0091] As discussed herein, the particle size and mix of base materials are the key to achieving this balance.

[0092] Specifically, there are several different aspects of water capacity for a plant growing medium, with the two most referenced being water holding capacity and easily available water. As the plants need access to the nutrient solution to grow, both the total amount of water that the media can hold, and how easy is it for the medium to take on that water plays a large role in how successful a given media will be.

[0093] For example, products that are hydrophobic, such as some hemp products, tend to be very slow to absorb water and to translocate the water to the top of the medium. Instead, water dries from the top which results in seedling death from drought. Other materials, such as some alfalfa products, absorb water quickly and translocate the water throughout the medium, but do not release it, which kills the seedlings by drowning.

[0094] That is, the seedlings are effectively starved for oxygen, but not necessarily from the release of the water as much as too high of a saturation level which results in water displacing the air space in the medium.

[0095] Room for the plant’s root develop and movement throughout the media is achieved by creating the correct aeration of the media. For example, as known by those of skill in the art, too much aeration leads to a rapid drying out of the media, similar to sand and is not desirable for optimum growth. Conversely, too little aeration results in water-logged mediums or soils which in turn leads to stunted plant growth and ultimately drowning. Too much water present for too long of a time also creates conditions favourable for disease, bacteria and moulds.

[0096] For reference, too much aeration is characteristic of a sand, while too little aeration is a characteristic of clay. Conversely, clay loam soils are considered the best in nature, as they have a mix of larger and finer particles.

[0097] While homogenous and heterogenous mixes will work in a similar fashion, different grades of the same materials work better than only particles of one grade. This is primarily due to the static water retention and release properties of a single material. Specifically, with a mix of comparatively larger and smaller particles, in addition to providing different size voids within the material for both water and air, smaller particles will for example release water sooner than the larger particles.

[0098] Particle size ranges from 0.1 to 10 mm. A mix of small and large particle sizes are required for a successful plant growing medium. In some embodiments, the particle sizes range from 0.1 -10 mm with over 60% of the material being less than 2 mm by weight. In some further embodiments, the particles of the plant growing medium prior to molding into a structure have a smooth, non-stepped particle distribution curve that is over 60% less than 2 mm by weight. As will be appreciated by those of skill in the art, the smooth particle distribution curve results in an even rate of water absorption and draining whereas a stepped curve would not be as even and could result in an uneven water distribution through the material.

[0099] Specifically, water is held in the voids between the small particles, while the voids between large particles drains water and promotes oxygen entry.

[0100] As discussed herein, the structure and functional properties of the growing medium are designed to capture water in the described air:water ratio. Similar to soil, loams are the best for most production due their ideal mix of sand and clay, whereby the clay portion holds moisture tightly and sand portion allows the moisture to move into the soil profile. As discussed herein, this is accomplished by using different particle sizes and different materials to maintain the desired air:water ratio, which is essentially the holding capacity of the medium.

[0101] The mix of specific particle sizes provides optimal air space, as well as water absorption and release, which are attributes that are beneficial to plant growth and health. Specifically, by modifying the particle size, we can increase or decrease the air space and surface areas to an optimum extent.

[0102] As will be apparent to those of skill in the art, for water soluble nutrients, such as for example nitrogen, the particle size will not matter other than to time the breakdown of the particle to provide sustained nutrition. In contrast, water insoluble particles are on the smaller end of the scale (<325 mesh). For example, in some embodiments, sustained feeding can be provided to the plants by preparing a growth medium with a mix of more soluble with less soluble nutrients, for example, a MAP phosphate with Struvite (an organic based less water-soluble form). Similarly, mixtures of sulfate-based and oxide-based minerals, such as for example, zinc, copper and the like could be used so that some sources of the nutrients are available for immediate uptake whereas other sources of the nutrients are taken up more slowly, that is, become available more slowly to the plants.

[0103] Specifically, in general, oxide forms are comparatively less soluble than corresponding sulphate and chelated / complexed forms of nutrients.

[0104] For example, for supplying zinc for lettuce, a mix of 25%-50% comparatively high solubility, 25-50% comparatively mid solubility, and 25-50% comparatively lower soluble may be used. This provides a sustained availability over the production cycle and reduces the amount of leaching and nutrient interactions at any given time, for example, interactions between phosphate and zinc.

[0105] Similarly, for supplying tomatoes with calcium may use 25-50% calcium nitrate, 25-50% calcium sulphate and 25-50% calcium carbonate.

[0106] It is of note that while tomatoes and lettuce are used above, mixes of this type could be used with different plants as well, although the specific percentage used at each of the three stages would depend on the target plant, examples are actually applicable to multiple plants, the total amount of each would differ based on the crop

[0107] As will be apparent to those of skill in the art, by using less soluble forms of the nutrients, that is, not immediately available, highly soluble forms of the nutrients, we are able to maintain the profile of that nutrient in the media. This means that rather than having the water being the only vehicle for the nutrients, we are creating a nutritional zone in the growing medium. The benefit of this is that when transplanting, the media being planted along with the plant has nutrients in it, so the transition from a greenhouse to the garden / field will be less stressful as the nutrient placement is already in the root zone. Secondly it decreases the amount of nutrients in the “waste” water and thus makes disposal easier and cleaner. This also reduces the fertility of the water in the tanks which in turn prevents the development of conditions ideal for growth of for example algae in the water. Most importantly, more applied nutrients remain in the root zone, not in the water.

[0108] As discussed herein, in some embodiments, binding agents are used to maintain the structure of the media while allowing for the physical movement of the plant and block within a growing area which is important as is maintaining the integrity to prevent particles from clogging pumps or drains within growing systems.

[0109] In these embodiments, a binder helps to shape the material into a useful shape and one that will maintain its structure in high moisture conditions. The binder may have additional attributes for attracting or repelling moisture as well as assisting in the physical structure of the medium produced. The binder may also have agronomic benefits to crop production. Suitable binders include but are by no means limited to starch-based products, molasses and organic acids. The binders may also be used to adjust the pH of the product.

[0110] For example, one advantage of starch as binding agent, is that it will also work as a source of carbon to the plant and, similar to sugar, the starch will provide early and available energy to the plants, resulting in faster growth primarily by faster root growth which inherently results in quicker and broader access to nutrients in the medium.

[0111] In some embodiments, a wrapper, for example, a bio plastic wrapper or a biodegradable paper or cardboard wrapper that promotes retention of water by allowing inflow and restricting outflow. As will be appreciated by one of skill in the art, this promotes a one-way flow of moisture (towards the plant) which in turn helps maintain adequate moisture levels

[0112] Furthermore, this wrapper will also help maintain the structural integrity of the media due to the airspace requirements. For example, as discussed above, the wrapper is biodegradable and / or compostable such that the wrapper will not break down while the plant is growing in a greenhouse or indoor farm, but if transplanted into outdoor soil, the wrapper will break down over the plants’ lifetime in most cases.

[0113] Due to the hydroponics nature of the system, all nutrients must be water soluble. This primarily means that all must be chelated, primarily with EDTA or HEPDTA, which are very strong chemical acids. These have proven problematic in other agricultural applications due to their propensity to leach and the persistence of the acids in groundwater. By incorporating the minerals in the growing medium utilizing specific particle sizes and distribution, we are able to use products not necessarily using the chemical chelating process as mobility in the water and growing medium are no longer essential, and root interception can be the primary feeding source.

[0114] Currently, all nutritional products are supplied primarily through mixing them with water in a tank and irrigating the mediums. Due to the mechanical nature of this system, the nutrients need to stay in solution or they will plug up the system and / or settle in the bottom of the flood trays. The end result is that the nutrients will not be absorbed by the growing medium as osmosis is required to translocate them into the mediums. In contrast, our method incorporates the nutrients throughout the medium profile, so that hydration of the medium will activate the soluble portions and root interception will provide a secondary source. Furthermore, as the soluble portions are used up or leached, the less soluble portions will remain in the plants root zone.

[0115] In some embodiments of the invention, there is provided an additional phase for fortifying the crop itself, for instance, for increasing zinc or iron levels (and in the future vitamins) by adding these components to the growing medium as feedstock, again with the advantage that these additives do not necessarily need to be water soluble.

[0116] Furthermore, by incorporating the nutrients into the growing medium during the production thereof, this ensures equal distribution throughout the medium. Furthermore, in some embodiments, varying particle sizing of the nutrients will in turn vary the release rate / timing so as to provide a sustained release effect in each unit, as discussed above.

[0117] By placing the nutrients into the growing medium, we are also able to have the specific nutrients for each plant available in a single rack or tier of a growing station. Currently, with the nutrients needing to be mixed in the water, plants of different species or at different stages of growth all get the same nutrition. Our system negates the need for multiple racks or tanks for production. It will also allow for a reduction of labour and resources needed to manage a growing system by reducing or eliminating the need to add materials to the water source. Is should also reduce the amount of nutrients in the water at the time of its disposal.

[0118] Essentially, nutrients are provided, for example, in the molded structure, effectively creating an artificial soil. In these embodiments, simply irrigating the plants will activate the fertilizer incorporated into the molded structure made from the growing medium. Furthermore, in these arrangements, the growing medium or molded structures formed therefrom can be tailored for specific plants, examples of which are provided above. While the preferred embodiments of the invention have been described above, it will be recognized and understood that various modifications may be made therein, and the appended claims are intended to cover all such modifications which may fall within the spirit and scope of the invention.

[0119] Table 1 : Grodan retention study (no plants)

[0120] Gordan A4 hole and Groblock 1” hole

[0121] Dimensions 3.0 x 3.0 x 2.5

[0122] 1) Non-Hydrated Weights

[0123] 2) Hydrated 15 min in H2O

[0124] 3) Saturated 15 min in H2O 4) 12 Hours

[0125] 5) 24 Hours

[0126] H2O:Air- 6.96:1 (A4), 7.11:1 (1”) Table 2 - Formulae examples

[0127] Binders Bulk Fibers W.A.B.D

[0128] Oat Hulls Pea Lignin Peat Compost Typha Pea pod Hemp hurd Hemp Flax Pea Straw bulk density 0.46 0.32 1 .13-.17 .42-.65 .3-.33 .3-.4 .097-.118 .07-.08 1.45-1.5 0.11

[0129] 5 averages 0.46 0.32 .55 .15 .535 .315 .35 .1075 .075 1.475 0.11

[0130] 1 .01 0.94 0.05 0.150

[0131] 2 .05 0.65 0.30 0.098

[0132] 3 0.05 0.65 0.30 0.105

[0133] 1 0 4 0.05 0.20 0.75 0.142

[0134] 5 .05 0.70 0.25 0.140

[0135] 6 .05 0.65 0.15 0.15 0.172

[0136] 7 .05 0.35 0.10 0.20 0.30 0.144

[0137] 8 0.05 0.05 0.10 0.60 0.20 0.182

[0138] 1 5 9 .01 0.34 0.40 0.25 0.127

[0139] 10 .05 0.10 0.60 0.20 0.05 0.128

Claims

CLAIMS1 . A plant growing medium comprising:0.5-5.0% (w / w) binder;10-84% (w / w) bulk material; and15-40% (w / w) fiber material.

2. The plant growing medium according to claim 1 wherein the binder is selected from the group consisting of ground oat hulls, pea starch, corn starch, potato starch, lignin, molasses, a suitable organic acid, corn syrup and a suitable ethanol syrup.

3. The plant growing medium according to claim 1 wherein the bulk material is selected from the group consisting of typha, bulk peas, chopped pea pods, peat, compost, hemp hurd, biochar, corn, corn distiller grains, potato, canola, wheat, distilled wheat from ethanol production, malting by-products such as those from barley, wheat and corn, bark, and paper and / or wood production by-products.

4. The plant growing medium according to claim 1 wherein the fiber material is selected from the group consisting of coconut coir, straw, cereal chaff, hemp, and flax.

5. The plant growing medium according to claim 1 wherein the growing medium is packaged as a loose fill product.

6. The plant growing medium according to claim 1 wherein the growing medium is molded as a shaped product for holding a plant therein.

7. The plant growing medium according to claim 6 wherein the shaped product comprises a wrap material placed around an exterior of the shaped product to hold the shaped product together.

8. The plant growing medium according to claim 7 wherein the wrap is biodegradable and / or compostable.

9. The plant growing medium according to claim 8 wherein the wrap is a cellulose wrap, a bioplastics wrap, a polylactic acid (PLA) wrap, a paper wrap or a straw pulp wrap.

10. The plant growing medium according to claim 6 wherein the shaped product is a pot, a planter, a pod or a block.1 1. A plant growing medium comprising: a bulk density of 0.05-0.15 g / cm3; pore volume of 75-98%; particle size of 0.1 -10 mm; air content of 25-70%; easily available water of 40-90%; and a water holding capacity of 500-800 mL / L.

12. The plant growing medium according to claim 1 1 wherein the growth media hols 5-9 times its dry weight of water.

13. The plant growing medium according to claim 1 1 wherein the growing medium comprises organic matter.

14. The plant growing medium according to claim 13 wherein the growing medium comprises organic matter breakdown products.

15. The plant growing medium according to claim 1 1 wherein the growing medium comprises material derived from one or more of pulses, hemp, oat andflax.

16. The plant growing medium according to claim 15 wherein the pulses comprise pulse straw and pulse hulls.

17. The plant growing medium according to claim 15 wherein the hemp comprises hemp hurd and fibers.

18. The plant growing medium according to claim 15 wherein the oat comprises oat hulls.

19. The plant growing medium according to claim 15 wherein the flax comprises flax fibers.

20. The plant growing medium according to claim 15 wherein the material derived from one or more of pulses, hemp, oat and flax is sterilized prior to incorporation into the growth medium.

21. The plant growing medium according to any one of claims 1 1 -20 wherein the growth medium further comprises a binding agent for producing a formed growth medium article.

22. The plant growing medium according to claim 21 wherein the binding agent is a starch-based product, molasses, or a suitable organic acid.

23. The plant growing medium according to claim 21 wherein the formed growth medium article is wrapped in a wrapper arranged to promote water inflow while restricting water outflow.

24. The plant growing medium according to claim 23 wherein thewrapper is a bioplastic wrapper, a biodegradable paper wrapper or a biodegradable cardboard wrapper.

25. The plant growing medium according to claim 1 wherein the growing medium comprises:(a) 3-10% ground oat hulls or pea starch, 50-70% hemp fiber, 20-40% pea straw, 0-5% plant-tailored nutrients;(b) Recipe #4 = 3-10% ground oat hulls or pea startch, 10-20% typha, 75-85% hemp fiber, 0-5% plant-tailored nutrients; or(c) 3-10% pea starch or ground oat hulls, 35-45% peat, 10-20% typha, 15-25% hemp hurd, 25-35% hemp fiber, 0-5% plant-tailored nutrients.

26. The plant growing medium according to claim 1 characterized in that physical characteristics of the plant growing medium or an article formed therefrom comprises: a bulk density of 0.05-0.15 g / cm3; pore volume of 75-98%; particle size of 0.1 -10 mm; air content of 25-70%; easily available water of 40-90%; and a water holding capacity of 500-800 mL / L.

27. The plant growing medium according to claim 1 wherein components of the plant growing medium are composed of particles that range from 0.1 -10 mm in diameter.

28. The plant growing medium according to claim 27 wherein over 60% of the particles are less than 2 mm in diameter (w / w).

29. The plant growing medium according to claim 28 wherein theparticles have a smooth, non stepped distribution curve.

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