Self-supporting growing media substrate made of wood fibers, uses and methods thereof

Abstract

The present application relates to growing media for hydroponic horticulture. More specifically, the present application relates to a self-supporting growing media substrate for hydroponic horticulture, comprising: wood fibers homogenously mixed with an organic binder and orderly oriented to form the self-supporting substrate, an organic coating applied on at least one surface of the self-supporting substrate. The present application also includes methods and uses of the self-supporting substrate.

Description

SELF-SUPPORTING GROWING MEDIA SUBSTRATE MADE OF WOOD FIBERS,USES AND METHODS THEREOF CROSS REFERENCE TO RELATED APPLICATION

[0001] The present application claims the benefit of priority from U. S. provisional application no. 63 / 737,345 filed on December 20, 2024, the content of which is incorporated herein by reference in its entirety.FIELD

[0002] The present application is in the field of horticulture. More specifically, the present application relates to growing media for hydroponic horticulture.BACKGROUND

[0003] Decreasing arable land, rising urbanization, water scarcity, and climate change exert pressure on agricultural producers. The environmental impact of plant cultivation is attracting considerable interest. Consumer preferences are changing in favour of sustainable production characteristics such as locally sourced materials and biodegradable containers.

[0004] The demand for sustainable and environmentally friendly growing media as alternatives for peat or inorganic substrates like Rockwool® for vegetable production in greenhouses is increasing. At the same time growing media must meet the requirements of the growers with respect to crop performance (yield, product quality) and consistent supply of high-quality raw material.

[0005] Greenhouse production area is increasing worldwide. The reasons for greenhouse cultivation are obvious. It is possible to optimize all limiting environmental factors as well as cultivation parameters such as growing medium. A successful substrate must perform under practical conditions and constraints equal or better as a commercially available standard to be accepted by growers.

[0006] Soilless plant culture serves as an umbrella term for all types of cultivation, where the plant roots are not in direct contact with the topsoil. In this type of cultivation, the plants may be grown in substrates and have nutrients given with irrigation or simply in a nutrient solution without any growing medium at all.

[0007] Hydroponics is a method of growing plants without soil by using a nutrient-rich water solution that supplies essential minerals directly to the plant roots. In hydroponic systems, plants are often supported by inert mediums like clay pellets, coconut coir, peat moss or stone wool to keep them stable while allowing their roots direct access to water, oxygen, and nutrients. This method is highly efficient, using less water than traditional soil-based agriculture because it recirculates water, reducing waste and optimizing resource use. Other benefits include the lack of soil-borne pathogens, high yield with good quality and efficient use of nutrients with less leaching to surroundings, including faster plant growth, higher yields, and the ability to cultivate crops in areas with limited or poor soil conditions, such as urban environments or arid regions. Additionally, because hydroponic systems can be controlled in terms of light, temperature, and humidity, they offer an ideal solution for indoor farming and vertical agriculture.

[0008] Only a few organic or inert materials have physical and chemical properties suitable for successful hydroponic production. Peat, one of the most popular and universal growing media in horticulture, has many drawbacks. Peatland exploration causes changes in landscape and stimulate the release of sequestered carbon into the environmental carbon cycle. Because of more restrictive policy regulations towards the use of this material, increased efforts are necessary to develop an alternative. Coconut fiber (coir) is an alternative material common in hydroponic plant production, nonetheless, it has a noticeable CO2footprint mainly due to its transportation and a noticeable impact on ecosystem quality due to the pollution of the large amount of water used to rinse and buffer the raw coir material. Mineral wool is an inert growing medium successfully used for production, however, production and recycling of this material is energy consuming and has a high CO2footprint.

[0009] Today, stone wool remains one of the major greenhouse substrates in Europe and North America. Inorganic and synthetic organic components of soilless culture and potting mixtures for substrates can be grouped into two categories of materials: (1) “inorganic substrates” which consist of natural unmodified materials (sand, tuff, pumice) and (2) “synthetic substrates” which consist of processed materials(such as stone wool, perlite, vermiculite, expanded clay, zeolite, and foamed glass). Synthetic organic materials include substrates such as phenolic resin or polyurethane.

[0010] The application of modified forms of stone wool as a substrate for horticulture started in Denmark in 1969. Through various corporate transitions the GRODAN Group emerged and by the 1980s its flagship product “rockwool” became widely synonymous with stone wool. Its use in horticulture is mainly in form of slabs or blocks of bonded fibers. Rockwool® is manufactured by heating a mixture (1600°C) of three natural raw materials: 60% diabase (a form of basalt rock, dolerite), 20% limestone, and 20% coke. Because Rockwool® does not naturally decompose, the excessively high waste volume is a major environmental concern.

[0011] In addition to Rockwool® (RC), peat is also used extensively as a cultivation substrate in horticulture because of its desirable physicochemical and biological properties for plant growth. It was estimated that about 40 million m3of peat is used annually worldwide in horticultural production (Kuisma et al., 2014). Unlike RC, peat is an organic material that can be easily recycled and reused. However, in recent years environmental and ecological concerns raised the demand for reducing the use of peat as its harvest affects endangered wetland ecosystems worldwide.

[0012] Wood fiber may be envisioned to be used in horticulture as an eco-friendly substrate alternative to traditional media like peat or synthetic materials. However, wood fiber materials most widely used are typically obtained from extensive secondary processing methods. Wood fibers are rarely used as a stand-alone growing media component because they tend to easily lose volume with compaction (shrink).

[0013] Despite good air contents and high saturated hydraulic conductivities, wood industry by-products have low water retention capacities. Several studies reported limitations to plant growth and fruit production with these growing media that was attributed to low water availability, insufficient aeration of growth media caused by microbial activity, or inappropriate particle-size distribution, and nutrient immobilization, as well as negative effects due to salt and toxic compound accumulations.

[0014] Physical breakdown of the growing medium can have a detrimental effect on crops which have a long production period such as woody nursery stock. Crops thathave a high aeration requirement cannot be grown well under wet conditions (e.g., ebb and flood systems). In this situation, the physical stability of the growing medium becomes important in maintaining favorable growing conditions for the whole period.

[0015] Other known hydroponic substrates featuring a fibrous structure are composed of compressed layers with varying wood fiber densities to create a waterretaining medium for hydroponic systems seeking alternatives to traditional stone wool and peat.

[0016] To sum up, consumer demand for sustainably grown products, using biodegradable and locally sourced materials, intensifies the need for eco-friendly alternatives to peat and inorganic substrates. However, these substrates must meet growers' performance requirements in terms of yield and quality, while also adapting to new environmental and regulatory constraints.

[0017] Based on the above, there is a need for a high-performance, monolithic, three-dimensional, self-supporting hydroponic substrate that would overcome at least some of the above drawbacks which meets economic, social, and environmental requirements.SUMMARY

[0018] It has been shown herein that substrates of the present application using wood fibers and organic additives provide for an environmentally friendly self-supporting hydroponic growing media substrate.

[0019] Accordingly, the present application includes a self-supporting growing media substrate for hydroponic horticulture, comprising: wood fibers homogenously mixed with an organic binder and orderly oriented to form the self-supporting substrate, and an organic coating applied on at least one surface of the self-supporting substrate.

[0020] Also included is a self-supporting growing media substrate for hydroponic horticulture, comprising: wood fibers homogenously mixed with an organic binder and orderly oriented to form the self-supporting substrate, and a rigid layer formed on at least one surface of the self-supporting substrate.

[0021] Also included is a self-supporting growing media substrate for hydroponic horticulture, comprising: wood fibers homogenously mixed with an organic binder and orderly oriented to form the self-supporting substrate.

[0022] The present application further includes a method for forming a self-supporting growing media substrate for hydroponic horticulture, the method comprising: mixing wood fibers with an organic binder to provide a homogeneous mixture, air laying the mixture to orderly orient the wood fibers to form a substrate; spraying an organic coating on at least one surface of the substrate to from the self-supporting growing media substrate.

[0023] The present application also includes use of wood fibers to prepare a biodegradable self-supporting growing media substrate for hydroponic horticulture.

[0024] Further included is use of the self-supporting growing media substrate of the present application for hydroponic horticulture.

[0025] Other features and advantages of the present application will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating embodiments of the application, are given by way of illustration only and the scope of the claims should not be limited by these embodiments, but should be given the broadest interpretation consistent with the description as a whole.BRIEF DESCRIPTION OF DRAWINGS

[0026] The embodiments of the application will now be described in greater detail with reference to the attached drawings in which:

[0027] FIG.1 shows pictures of substrates, where the top pictures are nonordered fibers, and the bottom pictures show orderly, isotropic, orientation according to exemplary embodiments of the application.

[0028] FIG.2 shows a bar graph of wettability results (water retained) by submersion according to exemplary embodiments of the application.

[0029] FIG.3 shows a bar graph of wettability results (saturation time) by submersion according to exemplary embodiments of the application.

[0030] FIG.4 shows a bar graph of wettability results (water retained) by watering according to exemplary embodiments of the application.

[0031] FIG.5 shows pictures of side view, top view and perspective view of substrates according to exemplary embodiments of the application, where the top row is with latex as the organic coating, and bottom row is with starch as the organic coating.

[0032] FIG.6 is a schematic representation of a plant growth performance testing in a greenhouse setup, according to exemplary embodiments of the application.

[0033] FIG.7 is a schematic representation of a plant growth performance testing in a greenhouse setup, according to exemplary embodiments of the application.

[0034] FIG.8 shows pictures of a plant growth performance testing in a greenhouse setup, according to exemplary embodiments of the application.

[0035] FIG.9 shows pictures of a root system growth analysis, according to exemplary embodiments of the application, with bottom views (left column), side views (center) and truncated view (right column), and where the top row pictures are with stone wool substrate, the middle row pictures are with an exemplary substrate of the present application, and the bottom row pictures are with a hemp substrate.

[0036] FIG.10 shows a graph of plant yield performance over time, according to exemplary embodiments of the application.

[0037] FIG.11 shows a graph of plant height at transplantation, according to exemplary embodiments of the application.

[0038] FIG.12 shows a picture of plant height at transplantation, according to exemplary embodiments of the application.DETAILED DESCRIPTIONI. Definitions

[0039] Unless otherwise indicated, the definitions and embodiments described in this and other sections are intended to be applicable to all embodiments and aspects of the present application herein described for which they are suitable as would be understood by a person skilled in the art.

[0040] As used in this application and claim(s), the words "comprising" (and any form of comprising, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "include" and "includes") or "containing" (and any form of containing, such as "contain" and "contains"), are inclusive or open-ended and do not exclude additional, unrecited elements or process steps.

[0041] The term “consisting” and its derivatives as used herein are intended to be closed terms that specify the presence of the stated features, elements, components, groups, integers, and / or steps, and also exclude the presence of other unstated features, elements, components, groups, integers and / or steps.

[0042] The term “consisting essentially of’, as used herein, is intended to specify the presence of the stated features, elements, components, groups, integers, and / or steps as well as those that do not materially affect the basic and novel characteristic(s) of these features, elements, components, groups, integers, and / or steps.

[0043] The terms "about", “substantially” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree should be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies or unless the context suggests otherwise to a person skilled in the art.

[0044] As used in the present application, the singular forms “a”, “an” and “the” include plural references unless the content clearly dictates otherwise. For example, an embodiment including “a component” should be understood to present certain aspects with one component, or two or more additional components.

[0045] In embodiments comprising an “additional” or “second” component, such as an additional or second component, the second component as used herein is different from the other components or first component. A “third” component is different from the other, first, and second components, and further enumerated or “additional” components are similarly different.

[0046] The term “and / or” as used herein means that the listed items are present, or used, individually or in combination. In effect, this term means that “at least one of” or “one or more” of the listed items is used or present.

[0047] The term “composition of the application” or “composition of the present application” and the like as used herein refers to a composition comprising one or more components of the application.

[0048] The term “suitable” as used herein means that the selection of the particular components or conditions would depend on the specific steps to be performed, the identity of the components to be used and / or the specific use for the components, but the selection would be well within the skill of a person trained in the art.II. Compositions and Substrates of the Application

[0049] It has been shown herein that substrates of the present application using wood fibers and organic additives provide for an environmentally friendly self-supporting hydroponic growing media substrate.

[0050] Accordingly, the present application includes a self-supporting growing media substrate for hydroponic horticulture, comprising: wood fibers homogenously mixed with an organic binder and orderly oriented to form the self-supporting substrate, and an organic coating applied on at least one surface of the self-supporting substrate.

[0051] In some embodiments, the wood fibers are from a coniferous species, hardwood species or a combination thereof. In some embodiments, the wood fibers are from fir, spruce, pine, aspen or a combination thereof. In some embodiments, the wood fibers are from wood chips, forestry or sawmill waste, or a combination thereof. In some embodiments, the wood fibers are orderly oriented in an isotropic configuration, for example through an airlaid process. Without being bound to theory, the isotropic orientation of the fibers allows for good water retention provided by a horizontal fiber orientation, while allowing suitable configuration for root growth both vertically and horizontally. Exemplary orderly oriented fibers are shown in FIG.1, wherein the top pictures are non-ordered fibers, and the bottom pictures show orderly, isotropic, orientation according to some embodiments of the present application. Insome embodiments, the wood fibers are homogenously mixed with the organic binder to provide a uniform substrate, i.e. not layered, and having a substantially uniform density throughout the substrate.

[0052] In some embodiments, the organic binder is selected from lignosulfonate, microfibrillated cellulose, saccharides, and a combination thereof. In some embodiments, the substrate comprises about 5% to about 25% of the organic binder, based on the total weight of the substrate. In some embodiments, the substrate comprises about 10% to about 20% of the organic binder, based on the total weight of the substrate. In some embodiments, the organic binder is selected from polylactic acid (PLA) fiber such as Polyplant™, PLA / PLA bicomponent fiber such as eSUN™ and Layo™, PLA / Co-PLA bicomponent fiber such as Trevira™, PLA / PBS bicomponent fiber such as Trevira™, and a biodegradable fiber such as PrimaLoft Bio™.

[0053] In some embodiments, without being bound to theory, the organic coating is intended for stabilization of substrate (self-supporting), maintenance of the substrate’s integrity through a culture cycle, and for allowing handling of substrate without packaging. In some embodiments, the organic coating is selected from starches, natural latexes (such as Burma™), aqueous araminolic resins (such as ResiCare™), and a combination thereof. In some embodiments, the coating has a thickness of about 0.5mm to about 10mm. In some embodiments, the coating has a thickness of about 1mm to about 8mm. In some embodiments, the coating has a thickness of about 2mm to about 5mm. In some embodiments, the coating is applied in an amount about 100 g / m2to about 345 g / m2. In some embodiments, the coating is applied in an amount about 160 g / m2to about 275 g / m2.

[0054] In some embodiments, the substrate comprises about 5% to about 15% of the organic coating, based on the total weight of the substrate. In some embodiments, the substrate comprises about 8% to about 12% of the organic coating, based on the total weight of the substrate. Without wishing to be bound to theory, the organic coating should be compatible with the wood fiber to provide a biodegradable substrate, while having a good water resistance and maintaining integrity to thesubstrate so that it is self-supporting. In some embodiments, the organic coating is applied on more than one surface, for example on all surfaces of the substrate.

[0055] In some embodiments, the organic coating may be omitted and the present application thus provides a self-supporting growing media substrate for hydroponic horticulture, comprising: wood fibers homogenously mixed with an organic binder and orderly oriented to form the self-supporting substrate, and optionally a rigid layer formed on at least one surface of the self-supporting substrate.

[0056] In some embodiments, the self-supporting growing media substrate further comprises a wetting agent, such as non-ionic surfactant blend or non-ionic ethylene oxide derivatives. In some embodiments, the wetting agent is Pluronic™ or Fiba-zorb™. In some embodiments, the substrate comprises about 1% to about 15% of a solution of the wetting agent, based on the total weight of the substrate. In some embodiments, the substrate comprises about 1% to about 10% of a solution of the wetting agent, based on the total weight of the substrate. In some embodiments, the substrate comprises about 1% to about 5% of a solution of the wetting agent, based on the total weight of the substrate. In some embodiments, the substrate comprises about 0.1 % to about 1 % of the wetting agent, based on the total weight of the substrate. In some embodiments, the substrate comprises about 0.2% to about 0.8% of the wetting agent, based on the total weight of the substrate. In some embodiments, the substrate comprises about 0.3% to about 0.6% of the wetting agent, based on the total weight of the substrate.

[0057] To achieve favorable growing performance, a growing media must have good water retention and aeration capacities, while allowing proper root growth. Water retention is typically expressed as wettability as the amount of water retained by the substrate during the wetting process, whether by submersion which indicates the maximum water retention capacity of the substrate, or by watering which indicates the water retention capacity of the substrate when watered in actual greenhouse conditions. Without being bound to theory, a growing substrate must have sufficient water retention so that the water, as well as the fertilizers / nutrients the water may contains, are available to the plant, without completely evacuating the air from thesubstrate. The saturation time is a parameter that is limited by the specific conditions used in cultivation, for example the systems currently favored by greenhouse farmers operate with fixed saturation times. The purpose of maintaining substrate integrity when saturated, is to avoid the use of packaging or pot - in other words, it is desirable that the substrate be “self-supporting” throughout the cultivation cycle. As such, in some embodiments, the substrate has a wettability of about 550 g / L to about 1100 g / L. In some embodiments, the substrate has a wettability of about 600 g / L to about 850 g / L. In some embodiments, the substrate has a saturation time of about 50 s to about 450 s. In some embodiments, the substrate has a saturation time of about 50 s to about 100 s.

[0058] Similarly, another favorable property of a growing media is its structural integrity upon saturation. In some embodiments, the substrate of the present application has a deformation on saturation of about -10% to about 10 %, based on an initial volume of the substrate before saturation. In some embodiments, the substrate has a deformation on saturation of about -5% to about 5 %, based on an initial volume of the substrate before saturation. By deformation is intended a loss of structural integrity of the growing media.

[0059] In some embodiments, the substrate has a density of about 60 g / L to about 110 g / L. In some embodiments, the substrate has a density of about 80 g / L to about 100 g / L.

[0060] In some embodiments, the substrate further comprises a rigid layer on at least one surface. In some embodiments, the rigid layer is formed by spraying cold water on the desired surface (for example at about 150g / m2to about 250g / m2or at about 200g / m2), followed by hot pressing such surface at temperatures of about 120°C to about 230°C. In some embodiments, hot pressing is achieved by the calendaring of the substrate, wherein the sprayed surface is in contact with the heated cylinder of the calendaring equipment. In some embodiments, hot pressing is achieved in a static press, with a heating source or a heating plate, or belt press. Without being bound to theory, the presence of a rigid layer on the substrate may help maintaining the desired structural integrity of the substrate upon various manipulations such as fabricationprocess including cutting into desired dimensions, use for culture, etc. In some embodiments, the organic coating is omitted. In some embodiments, the organic coating is omitted and only a rigid layer is present.

[0061] In some embodiments, because the components of the substrate of the application are natural / organic, the self-supporting growing media substrate of the present application is biodegradable and thus provides an eco-friendly solution. In some embodiments, the substrate is substantially free of synthetic additives.

[0062] In some embodiments, the substrate forms a single unitary continuous piece. In some embodiments, the substrate may form a cube, a mat, a cylinder, or the like, but the shape of the self-supporting growing media substrate is not to be limited thereto.III. Methods and Uses of the Application

[0063] Furthermore, the present application includes a method for forming a self-supporting growing media substrate for hydroponic horticulture, the method comprising: mixing wood fibers with an organic binder to provide a homogeneous mixture, air laying the mixture to orderly orient the wood fibers to form a substrate; spraying an organic coating on at least one surface of the substrate to form the self-supporting growing media substrate.

[0064] In some embodiments, the method further comprises forming a rigid layer on at least one surface of the self-supporting growing media substrate. In some embodiments, the forming of the rigid layer comprises spraying cold water on the desired surface (for example at 200g / m2), followed by hot pressing such surface at temperatures of about 120°C to about 230°C. In some embodiments, hot pressing is achieved by the calendaring of the substrate, wherein the sprayed surface is in contact with the heated cylinder of the calendaring equipment. In some embodiments, hot pressing is achieved in a static press, with a heating source or a heating plate, or belt press.

[0065] In some embodiments, the method further comprises calendaring the self-supporting growing media substrate.

[0066] In some embodiments, the method further comprises perforating the self-supporting growing media substrate.

[0067] The present application also includes use of wood fibers to prepare a biodegradable self-supporting growing media substrate for hydroponic horticulture.

[0068] Also provided is use of the self-supporting growing media substrate as of the present application for hydroponic horticulture.EXAMPLES

[0069] The following non-limiting examples are illustrative of the present application.General MethodsWettability AnalysisSubmersion Test

[0070] The following steps were followed for each substrate:• Prepare a tank containing a fertilizer solution of 8-10 L at 1.5 ppm 20-8-20;• Measure weight and size of each substrate, here in the form of blocks, before submersion;• Place each block in the tank and note the time it takes for the block to be completely submerged in the solution;• Remove the blocks from the tank and let them drain;• Measure weight and size of each of the saturated blocks.Watering Test

[0071] The following steps were followed for each substrate:Prepare a tank containing a fertilizer solution of 2 L at 1.5 ppm 20-8-20;Measure weight and size of each block, before watering;Place each block on a rack above a receptacle;• Water each block with the 2L solution, for 10 seconds, pausing for 3 to 5 seconds, and watering again for 20 seconds;• Once the solution is completely poured, allow each block to drain;• Measure weight and size of each of the watered blocks.Example 1 - Comparative Analysis of Wettability

[0072] Cubic blocks of 10 x 10 x 6.5 cm were taken for each of:• Stone wool - comparative example• Wood fiber A alone - comparative example• Hemp fiber - comparative example• Wood fiber A + 0.4 wt.% wetting agent + organic binder 10 wt.% + organic coating 10 wt.% - exemplary substrate of the present application• Wood fiber B + 0.4 wt.% wetting agent + organic binder 10 wt.% + organic coating 10 wt.% - exemplary substrate of the present application.• Wood fiber C + 0.4 wt.% wetting agent + organic binder 10 wt.% - exemplary substrate of the present application.

[0073] Wood fibers A, B and C differ from the fiber sizes, where fiber A and C comprises larger fibers and fiber B comprises smaller fibers, having a higher content of fine particles. With wood fiber A and B, the organic binder used was a blend of lignosulfonate and microfibrillated cellulose (Exilva®), and the organic coating was starch; and with wood fiber C, the organic binder was a biosourced PLA bicomponent. The submersion test and watering test described above were conducted on each twice, number of repetitions (n) = 2. Results are shown in Table 1, 2, 3 and 4, and FIG. 2, 3 and 4.Table 1: Submersion Wettability ResultsWater mass / volumeAbsorption (g / L) vs Block (10 x 10 x 6.5 cm) Saturation time(s) block (g / L)stone wool (%) Stone wool 50 848.2 / Wood fiber A 745 735.8 -13.2 Hemp fiber 225 357.3 -57.9 Wood fiber A + wetting agent +84 847.3 -0.1 organic binder + organic coatingWood fiber B + wetting agent +58.5 644.1 -24.1 organic binder + organic coatingWood fiber C + wetting agent +22.5 841 -0.8PLATable 2: Watering Wettability ResultsWaterAbsorption (g / L) vs Block (10 x 10 x 6.5 cm) mass / volumestone wool (%) block (g / L)Stone wool 829.2 / Wood fiber A 484.5 -41.6Hemp fiber 180.5 -78.2Wood fiber A + wetting agent + organicbinder + organic coating 572.8 -30.9Wood fiber B + wetting agent + organicbinder + organic coating 834.5 0.6Wood fiber C + wetting agent + PLA 794.1 -4.2Table 3: Submersion Size Variation ResultsLength Width Height Volume Block (10 x 10 x 6.5 cm)Variation Variation variation variation (cm) % (cm) % (cm) % (L) % Stone wool -0.20 -2.0 -0.20 -2.0 -0.10 -1.5 -0.04 -5.4 Wood fiber A 0.90 8.7 0.50 4.9 -0.70 -10.9 0.01 1.6 Hemp fiber 0.00 0.0 0.00 0.0 0.00 0.0 0.00 0.0 Wood fiber A + wetting agent +organic binder + organic coating 0.05 0.5 0.25 2.5 0.35 5.3 0.06 8.5 Wood fiber B + wetting agent +organic binder + organic coating 0.00 0 0.00 0 0.20 2.8 0.02 2.8 Wood fiber C + wetting agent + PLA 0.20 3.9 0.15 3.0 0.55 14.4 0.05 21.8Table 4: Watering Size Variation ResultsBlock (10 x 10 x 6.5 cm) Length Width Height Volume Variation Variation variation variation (cm) % (cm) % (cm) % (L) % Stone wool 0.00 0.0 -0.20 -2.0 0.00 0.0 -0.01 -2.0 Wood fiber A 0.90 8.7 0.50 4.9 -0.70 -10.9 0.01 1.6 Hemp fiber 0.00 0.0 0.00 0.0 0.00 0.0 0.00 0.0 Wood fiber A + wetting agent +organic binder + organic coating 0.30 3.0 0.15 1.5 0.10 1.6 0.04 6.0 Wood fiber B + wetting agent +organic binder + organic coating 0.35 3.5 0.00 0.0 0.10 1.6 0.03 5.1 Wood fiber C + wetting agent +PLA 0.25 4.8 0.2 4.0 -0.25 -7.6 0.01 1.0 Example 2 - Parameters Analysis

[0074] The submersion test was conducted on various substrate blocks using different densities and organic coatings, as shown in Tables 5 and 6. Organic coating contents are expressed as a percentage of dry weight of coating / total weight of block, measured at 12% humidity. Table 7 shows the average density of each type of substrates.Table 5: Submersion Test ResultsWater weight / Saturation %Block (10 x 10 x 6.5 cm) substrate volumetime (s) % Length % Width(g / L) Height Volume Stone wool 848 50 -2.0 -2.0 -1.5 -5.4 Hemp 357 145 0.0 0.0 0.0 0.0 Wood Fiber A744 745 8.7 5.0 -10.9 1.6 (density: 80g / L)Wood Fiber A(density: 80g / L + Organic coating: latex) 705 866 11.1 6.1 -7.7 8.8Wood Fiber A(density: 100g / L + Organic coating: latex) 909 744 10.0 5.1 0.0 15.6Wood Fiber A(density: 80g / L + Organic coating: 833 1034 0.9 5.9 -9.1 -2.8 starch)Wood Fiber A(density: 10Og / L + Organic 964 1012 11.1 8.2 -7.9 10.7coating: starch)Table 6: Submersion Test ResultsLength Width Height Volume Block (10 x 10x 6.5cm) Variation Variation Variation Variation (cm) % (cm) % (cm) % (L) % Stone Wool -0.2 -2.0 -0.2 -2.0 -0.1 -1.5 -0.04 -5.4 Hemp 0 0.0 0 0.0 0 0.0 0.00 0.0 Wood Fiber A(Density: 80g / L)0.9 8.7 0.5 5.0 -0.7 -10.9 0.01 1.6 Wood Fiber A(Density: 80g / L +Organic coating: latex ) 1.1 11.1 0.6 6.1 -0.5 -7.7 0.06 8.8 Wood Fiber A(Density: 10Og / L +Organic coating: latex) 1 10.0 0.5 5.1 0 0.0 0.10 15.6 Wood Fiber A(Density: 80g / L +Organic coating: starch)0.1 0.9 0.6 5.9 -0.6 -9.1 -0.02 -2.8 Wood Fiber A(Density: 10Og / L +Organic coating: starch)1.1 11.1 0.8 8.2 -0.5 -7.9 0.06 10.7Table 7 Density of SubstratesFiber Type Density (g / L)Stone wool 64 -76Hemp 60-86Wood fiber + moss 119-162Wood fiber of the application 60-110Example 3 - Growth Performance Analysis

[0075] Plant cultivation was conducted to compare performances of the substrates of the present application (shown at FIG. 5) with comparative substrates (namely stone wool and hemp). Bell pepper plants were grown in different substrates for 21 days in blocks before being transplanted on slabs in a greenhouse setting. The propagation was conducted in subirrigation with a nutrient solution, then vegetative growth and production on slabs in fertigation with a system of dosing pumps (dosatrons) and dripper lines. Fertigation is a technique of applying soluble fertilizing elements to crops, via an irrigation system. A schematic representation of the cultivation system is shown in FIG. 6, and FIG.7 shows disposition of various plants and substrates. On FIG.7, a sample portion of plants, block 1, were equipped with lysimeters, that allows monitoring of the fertigation with various parameters’ measures and comparisons, for example by comparing the volume of fertilizing solution entering (provided on the slabs / cubes) to the volume exiting. Such parameters may also include pH of the solution, electrical conductivity, etc.

[0076] The growth performance analysis consisted in evaluating root growth, plant height, visual appearance of the plant (colour, size, etc.) and fruit production.FIG.8 are pictures of the plants in the greenhouse. Root growth results are shown in FIG.9 as bottom views (left) side views (center) and truncated view (right), where the top pictures are stone wool substrate, the middle pictures are the substrate of the present application, and the bottom pictures are hemp substrate. Data was collected on 12 plants for Wood fibers (TT) systems, 12 plants on stone wool (RR) and 4 plants on hemp fibers (CC), over a period of 20 weeks, from the implantation of the seedlings on the substrates. Results are presented in Table 8 and FIG. 10.Table 8: Growth Performance ResultsAverageAverage plantSubstrate production perheight (cm)plant (kg)Wood fiber (TT)4.08 150.18Stone wool (RR) 4.12 163.09Hemp Fiber (CC) 3.41 156.2

[0077] FIG.11 is a band graph of plant height at transplantation, i.e. after 21 days in blocks, before being transferred on slabs, and shows comparison between different substrates, where R is stone wool substrate, T is a substrate of the application and C is hemp substrate. FIG.12 is a picture further illustrating the same, with first two left are on stone wool substrates, middle two are on substrates of the application and two at the right are on hemp substrates.Results

[0078] Without being bound to theory, the following may be concluded from the above presented results:On water retention:

[0079] The self-supporting substrate has a water retention capacity comparable to the reference material used in greenhouse production, i.e. stone wool. It has a better water retention capacity than hemp, another organic substrate. On such parameter, the self-supporting substrate of the present application is thus a performant organic alternative to stone wool as it has similar water retention capacity for the plant.On saturation time:

[0080] The self-supporting substrate of the present application achieves better results than the hemp alternative. The minimal difference it presents when compared to stone wool means it can be incorporated into greenhouse production practices with minimal disruption.On size variation:

[0081] The self-supporting substrate of the present application does self-support without the need for a pot or bag. Such maintenance of integrity is comparable to stone wool, but is achieved without added synthetic man-made material. This allows it to be incorporated into greenhouse production practices with minimal disruption.On growth performance:

[0082] The self-supporting substrate of the present application is comparable to the reference material that is stone wool. It achieves similar growth and production per plant. It noticeably outperforms the hemp alternative. The self-supporting substrate is thus an alternative to inorganic materials in which the grower does not need to compromise on plant productivity.

[0083] While the applicant's teachings described herein are in conjunction with various embodiments for illustrative purposes, it is not intended that the applicant's teachings be limited to such embodiments as the embodiments described herein are intended to be examples. On the contrary, the applicant's teachings described and illustrated herein encompass various alternatives, modifications, and equivalents, without departing from the embodiments described herein, the general scope of which is defined in the appended claims.

Claims

CLAIMS1. A self-supporting growing media substrate for hydroponic horticulture, comprising:wood fibers homogenously mixed with an organic binder and orderly oriented to form the self-supporting substrate, andan organic coating applied on at least one surface of the self-supporting substrate.

2. The self-supporting growing media substrate of claim 1, wherein the wood fibers are from a coniferous species, hardwood species or a combination thereof.

3. The self-supporting growing media substrate of claim 1, wherein the wood fibers are from fir, spruce, pine, aspen, or a combination thereof.

4. The self-supporting growing media substrate of any one of claims 1 to 3, wherein the wood fibers are from wood chips, forestry or sawmill waste, or a combination thereof.

5. The self-supporting growing media substrate of any one of claims 1 to 4, wherein the organic binder is selected from lignosulfonate, microfibrillated cellulose, saccharides, and a combination thereof.

6. The self-supporting growing media substrate of any one of claims 1 to 5, wherein the organic coating is selected from starches, natural latexes, araminolic resins, and a combination thereof.

7. The self-supporting growing media substrate of any one of claims 1 to 6, wherein the coating has a thickness of about 0.5mm to about 10mm.

8. The self-supporting growing media substrate of any one of claims 1 to 6, wherein the coating is applied in an amount about 100 g / m2to about 345 g / m2.

9. The self-supporting growing media substrate of any one of claims 1 to 8, wherein the substrate comprises about 5% to about 25% of the organic binder, based on the total weight of the substrate.

10. The self-supporting growing media substrate of any one of claims 1 to 8, wherein the substrate comprises about 10% to about 20% of the organic binder, based on the total weight of the substrate.

11. The self-supporting growing media substrate of any one of claims 1 to 10, wherein the substrate comprises about 5% to about 15% of the organic coating, based on the total weight of the substrate.

12. The self-supporting growing media substrate of any one of claims 1 to 10, wherein the substrate comprises about 8% to about 12% of the organic coating, based on the total weight of the substrate.

13. The self-supporting growing media substrate of any one of claims 1 to 12, further comprising a wetting agent.

14. The self-supporting growing media substrate of claim 13, wherein the substrate comprises about 0.1 % to about 1 % of the wetting agent, based on the total weight of the substrate.

15. The self-supporting growing media substrate of claim 13, wherein the substrate comprises about 0.2% to about 0.8% of the wetting agent, based on the total weight of the substrate.

16. The self-supporting growing media substrate of claim 13, wherein the substrate comprises about 0.3% to about 0.6% of the wetting agent, based on the total weight of the substrate.

17. The self-supporting growing media substrate of any one of claims 13 to 16, wherein the wetting agent is selected from a non-ionic surfactant blend, nonionic ethylene oxide derivatives, and combinations thereof.

18. The self-supporting growing media substrate of any one of claims 1 to 17, wherein the substrate has a wettability of about 550 g / L to about 1100 g / L.

19. The self-supporting growing media substrate of any one of claims 1 to 17, wherein the substrate has a wettability of about 600 g / L to about 850 g / L.

20. The self-supporting growing media substrate of any one of claims 1 to 19, wherein the substrate has a saturation time of about 50 s to about 450 s.

21. The self-supporting growing media substrate of any one of claims 1 to 19, wherein the substrate has a saturation time of about 50 s to about 100 s.

22. The self-supporting growing media substrate of any one of claims 1 to 21, wherein the substrate has a deformation on saturation of about -10% to about 10 %, based on an initial volume of the substrate before saturation.

23. The self-supporting growing media substrate of any one of claims 1 to 21, wherein the substrate has a deformation on saturation of about -5% to about 5 %, based on an initial volume of the substrate before saturation.

24. The self-supporting growing media substrate of any one of claims 1 to 21, wherein the substrate has a deformation on saturation of about -10% to about 10 %, based on an initial length of the substrate before saturation.

25. The self-supporting growing media substrate of any one of claims 1 to 21, wherein the substrate has a deformation on saturation of about -5% to about 5 %, based on an initial length of the substrate before saturation.

26. The self-supporting growing media substrate of any one of claims 1 to 21, wherein the substrate has a deformation on saturation of about -10% to about 10 %, based on an initial height of the substrate before saturation.

27. The self-supporting growing media substrate of any one of claims 1 to 21, wherein the substrate has a deformation on saturation of about -5% to about 5 %, based on an initial height of the substrate before saturation.

28. The self-supporting growing media substrate of any one of claims 1 to 27, wherein the substrate has a density of about 60 g / L to about 110 g / L.

29. The self-supporting growing media substrate of any one of claims 1 to 27, wherein the substrate has a density of about 80 g / L to about 100 g / L.

30. The self-supporting growing media substrate of any one of claims 1 to 29, wherein the substrate is biodegradable.

31. The self-supporting growing media substrate of any one of claims 1 to 30, wherein the substrate is substantially free of non-biodegradable synthetic additives.

32. The self-supporting growing media substrate of any one of claims 1 to 31, wherein the substrate forms a single unitary continuous piece.

33. A self-supporting growing media substrate for hydroponic horticulture, comprising:wood fibers homogenously mixed with an organic binder and orderly oriented to form the self-supporting substrate, anda rigid layer on at least one surface of the self-supporting growing media substrate.

34. A method for forming a self-supporting growing media substrate for hydroponic horticulture, the method comprising:mixing wood fibers with an organic binder to provide a homogeneous mixture,air laying the mixture to orderly orient the wood fibers to form a substrate;spraying an organic coating on at least one surface of the substrate to from the self-supporting growing media substrate.

35. The method of claim 34, wherein the organic coating is sprayed in an amount about 100 g / m2to about 345 g / m236. The method of claim 34 or 35, further comprising forming a rigid layer on at least one surface of the self-supporting growing media substrate.

37. The method of claim 36, wherein forming the rigid layer comprises spraying cold water on the at least one surface, and hot pressing the self-supporting growing media substrate to provide the rigid layer.

38. The method of claim 37, wherein the cold water is prayed in an amount of about 150g / m2to about 250g / m239. The method of claim 37 or 38, wherein the hot pressing is conducted through calendaring, static press or belt press.

40. The method of any one of claims 37 to 39, wherein the hot pressing is conducted at a temperature of about 120°C to about 230°C.

41. The method of any one of claims 34 to 40, further comprising perforating the self-supporting growing media substrate.

42. A method for forming a self-supporting growing media substrate for hydroponic horticulture, the method comprising:mixing wood fibers with an organic binder to provide a homogeneous mixture,air laying the mixture to orderly orient the wood fibers to form a substrate;forming a rigid layer on at least one surface of the self-supporting growing media substrate to from the self-supporting growing media substrate.

43. Use of wood fibers to prepare a biodegradable self-supporting growing media substrate for hydroponic horticulture.

44. Use of the self-supporting growing media substrate as defined in any one of claims 1 to 33 for hydroponic horticulture.

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