CROSS-REFERENCE TO RELATED APPLICATIONS

[0001 ] This application claims priority to U.S. Provisional Application No. 63/026,880, filed on May 19, 2020, and titled "Plant Fertilizer Device". This application is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

[0002] The present invention, in some embodiments thereof, relates to plant fertilizer devices and more specifically but not exclusively to plant fertilizer devices with indicators.

BACKGROUND

[0003] Water-soluble fertilizers deposited in the ground or mixed with soil around plants or trees, typically disperse their nutrients quickly as the fertilizer dissolves, rather than slowly and in a controlled manner.

[0004] Certain water-insoluble fertilizers, such as urea-formaldehyde reaction products - a relatively expensive source of nitrogen - seldom provide the desired plant growth, as the fertilizer is not released in accordance with plant needs.

[0005] Sustained release formulations are mainly used in the pharmaceutical industry and are designed to release the pharmaceutically-active ingredients at a predetermined rate in order to maintain a stable drug concentration in the body for a specific period of time with minimum side effects.

[0006] Slow release devices for delivery of fertilizers currently known in the art are based on manual or automatic gates, valves and/or pumps, which are designed to deliver fertilizers upon demand. These devices, however, require a control unit, and are usually expensive.

[0007] Slow release compositions may also be beneficial for decontamination of water reservoirs, as shown, for example, in McKnight et al. (Water Resources Division, M.S. 407 The U.S. Geological Survey). McKnight et al. disclose that slow delivery of copper (II) sulfate disinfectant to a water reservoir in low concentrations results with better extermination of nuisance algae, without the side-effects often witnessed when providing the entire amount of disinfectants at one shot.

SUMMARY

[0008] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope.

[0009] In accordance with some embodiments of the invention there is provided a plant fertilizer device including: a container defining a fertilizer-holding portion including fertilizer and a superabsorbent polymer, the wall at the fertilizer-holding portion having one or more apertures, a hydration indicator portion in fluid communication with the fertilizer-holding portion at one end and forming an opening at a second end, and a cover over the opening at the hydration indicator portion including one or more fluid inlets. In some embodiments, the fertilizer device also includes a water-soluble barrier layer between the fertilizer-holding portion and the hydration indicator portion.

[0010] In accordance with some embodiments, the fertilizer-holding portion includes a fertilizer layer and a layer of a superabsorbent polymer disposed between the fertilizer layer and the water-soluble layer. In some embodiments, the cover includes at least one fluid inlet. In some embodiments, the fluid inlet is configured to allow evaporation of liquid from the container. In some embodiments, the fertilizer is water soluble and forms a fertilizer solution in the container. In some embodiments, a concentration of the fertilizer solution is constant.

[0011] In accordance with some embodiments, the cover includes a retainer that extends inwards, towards fertilizer-holding portion from a rim of the opening. In some embodiments, the retainer is cone-shaped. In some embodiments, a tip of the retainer is urged against the water-soluble layer. In some embodiments, the cover includes a retainer that extends inwards, towards fertilizer-holding portion from a rim of the opening and wherein in a pre-activation e.g., dry state, a tip of the retainer is urged against the water- soluble barrier layer and locks the layers in place. In some embodiments, the apertures provide fluid communication between the container and a circumambient environment around the container. [0012] In accordance with some embodiments, the fertilizer layer includes fertilizer in solid form. In some embodiments, the amount of fertilizer released from the container depends on a humidity gradient across the channels between the content of the container and a circumambient environment around the container. In some embodiments, the rate at which the fertilizer is released from the container depends on a size and quantity of the apertures. In some embodiments, release of the fertilizer from the container is controlled by water diffusion via the apertures. In some embodiments, quantity of the fertilizer in the fertilizer-holding portion is between 3 and 6 grams of a high-concentration fertilizer. [0013] In accordance with some embodiments, the layer of a superabsorbent polymer includes color-coded beads. In some embodiments, the superabsorbent polymer color- coded beads fill the hydration indicator portion in accordance with the hydration level of the container. In some embodiments, a wall of the hydration indicator portion includes light-dispersing protrusions. In some embodiments, a wall of the hydration indicator portion includes light-dispersing protrusions configured to disperse light reflected off the color-coded beads inside the hydration indicator portion. In some embodiments, the water-soluble barrier layer includes a pad or disc. In some embodiments, hydration of the container dissolves the water-soluble barrier layer and allows the layer of super absorbent beads to expand into the hydration indicator portion.

[0014] In accordance some embodiments of the invention there is provided a method of fertilizing a plant, including: combining a solvent and a fertilizer in solid form and forming a fertilizer solution, buffering between the fertilizer solution and a soil circumambient environment receiving a plant to be fertilized, providing channels in the buffer layer so that to allow seepage of a liquid through the buffer layer, and forming a humidity gradient to drive the fertilizer solution via the channels in the buffer layer to the soil circumambient environment. In some embodiments, the solvent is water. In some embodiments, the buffer layer is a wall of a container and the channels are apertures in the wall.

[0015] In some embodiments, the method also includes indicating a hydration status of the soil circumambient environment. In some embodiments, the method also includes providing color-coded super-absorbent beads to indicate the hydration status. In some embodiments, the method also includes indicating fertilizing requirement of the soil circumambient environment. In some embodiments, the method also includes controlling the amount of fertilizer released into the soil circumambient environment via a humidity gradient across the channels.

[0016] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed description.

BRIEF DESCRIPTION OF THE FIGURES

[0017] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanied drawings. Embodiments of the invention are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like reference numerals indicate corresponding, analogous or similar elements, and in which:

[0018] Fig. 1 is a cross section view simplified illustration of a fertilizer device in accordance with some embodiments of the present invention;

[0019] Fig. 2 is a side view simplified illustration of a fertilizer device in accordance with some embodiments of the present invention;

[0020] Fig. 3 is a cross section view simplified illustration of fertilizer device and contents in accordance with some embodiments of the present invention;

[0021] Figs. 4A, 4B, 4C, 4D, 4E, 4F are cross section view simplified illustrations of operation of a fertilizer device and 4G, which is a block diagram of the water balance in the device in accordance with some embodiments of the present invention;

[0022] Figs. 5A, 5B, 5C, 5D and 5E are cross-section view simplified illustrations of operation of a fertilizer device in accordance with some embodiments of the present invention; and

[0023] Figs. 6A, 6B and 6C are side view and cross-section view simplified illustrations of a fertilizer device hydration indicator in accordance with some embodiments of the present invention. [0024] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn accurately or to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity, or several physical components may be included in one functional block or element. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION

[0025] According to an aspect of some embodiments of the present invention there is provided a fertilizer device comprising a container defining (i) a fertilizer-holding portion including fertilizer and a superabsorbent polymer, and (ii) a hydration indicator portion, in fluid communication with the fertilizer-holding portion at one end, and forming an opening at a second end. In some embodiments, the superabsorbent polymer is coated with a water-permeable material or enclosed within a permeable capsule. In some embodiments, the device also comprises a cover configured to be placed over the opening at the hydration indicator portion, at the second end, the cover comprising one or more inlets. In some embodiments, the cover is cone-shaped inwards. In some embodiments, the inlets are liquid inlets.

[0026] In some embodiments, the container comprises a wall. The wall at the fertilizer holding portion comprises one or more apertures that provide fluid communication between the inside of the fertilizer-holding portion of the container and the environment outside the device wall. In some embodiments, the device fertilizer-holding portion comprises a fertilizer substance and a superabsorbent polymer layered between the fertilizer and the hydration indicator portion (i.e., over the fertilizer). In some embodiments, the device fertilizer-holding portion also comprises one or more layers of water-soluble material that covers the superabsorbent polymer and the fertilizer. In some embodiments, the cover comprises a water-soluble material holding element (e.g., a tip of the cone) that is urged against the water-soluble material to lock the superabsorbent polymer and fertilizer in place in the dry state.

[0027] According to an aspect of some embodiments of the present invention there is provided a fertilizer device comprising a container enclosed by a wall and defining (i) a fertilizer-holding portion including fertilizer and a superabsorbent polymer and (ii) a hydration indicator portion in fluid communication with the fertilizer-holding portion at one end and forming an opening at a second end. In some embodiments, and as explained in detail elsewhere herein, the device is configured to release a liquid-form fertilizer at a constant concentration. In some embodiments, the release of the fertilizer depends on the humidity of the circumambient soil environment outside the device. In some embodiments, the release of the fertilizer depends on the humidity of the circumambient non-soil environment e.g., atmosphere, outside the device. In some embodiments, the amount of fertilizer released into the soil environment outside the device depends on the humidity gradient across the apertures between the content inside of the device container and the humidity of the soil environment outside the device.

[0028] According to an aspect of some embodiments of the present invention there is provided a device comprising a container enclosed by a wall and defining (i) a fertilizer- holding portion or a sealed chamber and a superabsorbent polymer and (ii) a hydration indicator portion in fluid communication with a fertilizer -holding portion or a sealed chamber at one end and forming an opening at a second end. In some embodiments, and as explained in detail elsewhere herein, the device is configured to release a liquid-form fertilizer or a dry composition at a constant concentration. In some embodiments, the release of the fertilizer or the dry composition depends on the humidity of the environment outside the device. In some embodiments, the amount of dry composition released outside the device depends on the humidity gradient across the apertures between the content inside of the device container and the humidity of the environment outside the device.

[0029] According to an aspect of some embodiments of the present invention there is provided a fertilizer device comprising a container enclosed by a wall and defining (i) a fertilizer-holding portion including fertilizer and a superabsorbent polymer and (ii) a hydration indicator portion in fluid communication with the fertilizer-holding portion at one end and forming an opening at a second end. In some embodiments, the hydration indicator portion comprises light-dispersing protrusions. In some embodiments, light emitted by superabsorbent beads inside the hydration indicator portion is dispersed by the light-dispersing protrusions. In some embodiments, light passing through an empty hydration indicator portion is only partially or not dispersed at all by the light-dispersing protrusions.

[0030] In one embodiment, provided herein is a device comprising: a container defining: (a) A dry composition holding portion and a superabsorbent polymer, the wall at the dry composition holding portion having one or more apertures; (b) a hydration indicator portion in fluid communication with the dry composition holding portion at one end and forming an opening at a second end; and (c) a cover over the opening at the hydration indicator portion comprising one or more fluid inlets.

[0031] In one embodiment, dry composition is a drug, a fertilizer, a herbicide, a nutrient, a mineral, or a salt. In one embodiment, dry composition is in the form of a powder or dry particles. In one embodiment, dry composition comprises less than 5% w/w water. In one embodiment, dry composition comprises less than 4% w/w water. In one embodiment, dry composition comprises less than 3% w/w water. In one embodiment, dry composition comprises less than 2.5% w/w water. In one embodiment, dry composition comprises less than 1 % w/w water.

[0032] In one embodiment, a dry composition holding portion is adapted to maintain a dry composition as described herein as dry for at least a month in storage. In one embodiment, a dry composition holding portion is adapted to maintain a dry composition as described herein as dry for at least 6 months in storage. In one embodiment, “dry” is an amount of water of less than 5% of the weight of the dry composition. In one embodiment, “dry” is an amount of water of less than 6% of the weight of the dry composition. In one embodiment, “dry” is an amount of water of less than 3% of the weight of the dry composition. In one embodiment, “dry” is an amount of water of less than 2% of the weight of the dry composition. In one embodiment, “dry” is an amount of water of less than 1 % of the weight of the dry composition.

[0033] In one embodiment, the phrase “the fertilizer-holding portion” as used herein is substituted with the phrase “dry composition holding portion”. In one embodiment, the term fertilizer as used herein is substituted with the term dry composition. In one embodiment, a dry composition is preloaded within the dry composition-holding portion 106. In one embodiment, a dry composition is provided separately and can be loaded into the dry composition -holding portion 106. In one embodiment, provided herein is a kit separately comprising a dry composition and a device as described herein without the dry composition. In one embodiment, provided herein is a kit separately comprising a dry composition and a device as described to be loaded with the dry composition. In one embodiment, a fertilizer is a dry composition as described herein. In one embodiment, a fertilizer is preloaded within the fertilizer-holding portion 106. In one embodiment, a fertilizer is provided separately and can be loaded into the fertilizer-holding portion 106. In one embodiment, provided herein is a kit separately comprising a fertilizer and a device as described herein. In one embodiment, provided herein is a kit separately comprising a fertilizer and a device as described herein without the fertilizer.

[0034] Reference is made to Fig. 1 which is a cross section view simplified illustration of a device or a fertilizer device in accordance with some embodiments of the present invention. In some embodiments, a device or a fertilizer device 100 comprises a container 104 comprising a wall 102 and defining a fertilizer-holding portion or a dry composition holding portion 106 configured to accommodate a fertilizer or a dry composition and a superabsorbent polymer and (ii) a hydration indicator portion 108 in fluid communication with the dry composition-holding portion or the fertilizer-holding portion 106 at one end and forming an opening 110 at a second end. In some embodiments, the dry composition holding portion or the fertilizer-holding portion 106 comprises one or more apertures 120 that provide a fluid passageway through wall 102 of container 104 and fluidly communicate between the dry composition-holding portion or the fertilizer-holding portion 106 of container 104 and the outside environment or soil and/or non-soil circumambient environment outside device or fertilizer device 100.

[0035] In some embodiments, the device also comprises a cover 112 configured to be placed over the opening 110 at the hydration indicator portion 108, at the second end. In some embodiments, the cover 112 comprises one or more inlets 114 (Fig. 2). In some embodiments, the one or more inlets 114 form a sieve in cover 112.

[0036] In some embodiments, cover 112 is shaped as a retainer 116 extending inwards, generally perpendicular to opening 110 at the hydration indicator portion 108. In some embodiments, retainer 116 is cone-shaped extending inwards, towards fertilizer-holding portion 106 from the rim of opening 110 in which case retainer 116 and inlets 114 form a cone-shaped sieve. In some embodiments, inlets 114 are fluid inlets. In some embodiments, retainer 116 is a rod or any other suitable extension.

[0037] In some embodiments, the wall 102 at the fertilizer-holding portion comprises one or more apertures 120 that provide fluid communication between the inside of the container 104 and the circumambient environment outside the container wall. In some embodiments, the device fertilizer-holding portion comprises a fertilizer substance, and a superabsorbent polymer layered between the fertilizer and the hydration indicator portion (i.e., over the fertilizer). In some embodiments, the device fertilizer-holding container also comprises one or more layers of water-soluble material that covers the superabsorbent polymer and the fertilizer. In some embodiments, the cover comprises a water-soluble material holding element (e.g., a tip of the cone) that is urged against the water-soluble material to lock the superabsorbent polymer and fertilizer in place in the dry state.

[0038] In some embodiments, a cross-section diameter of fertilizer-holding portion 106 of fertilizer device 100 is smaller than a cross-section diameter of hydration indicator portion 108. In some embodiments, fertilizer device 100 container 104 has a mushroom shaped geometry where hydration indicator portion 108 forms the cap of the mushroom shape and the fertilizer-holding portion 106 forms the stalk of the mushroom and comprises a pointed or conical tip 122. In some embodiments, wall 102 of fertilizer holding portion 106 comprises a thread 124 on an external surface 126 thereof to facilitate rotational threaded insertion of fertilizer device 100 into soil e.g., hard soil or a stone medium e.g., tufa, tuff or travertine (e.g., for orchids).

[0039] In some embodiments, the diameter or width of hydration indicator portion 108 is between 2 and 6cm or between 2 and 4 cm. In some embodiments, the diameter or width of hydration indicator portion 108 is between 2.5 cm and 3.5 cm. In some embodiments, the length of fertilizer device 100 is between 2 and 8cm, 3 and 7cm or between 4.5 and 5.5 cm. In some embodiments, a fertilizer device 100 within the described dimensions is suitable for fertilizing a plant in a flowerpot or planter having a diameter between 20 and 40cm or 25 and 35cm for 12 months.

[0040] Reference is now made to Fig. 2, which is a side view simplified illustration of a fertilizer device in accordance with some embodiments of the present invention. As shown in the exemplary embodiment depicted in Fig. 2, fertilizer device 100 comprises a container 104 defined by a wall 102 open to one side at an opening 110 and a cover 112 sized and fitted to be placed over opening 110 of container 104. In some embodiments, cover 112 comprises one or more fluid inlets 114 providing cover 112 a sieve form. In some embodiments, and as explained in greater detail elsewhere herein, fluid inlets 114 provide passageway for fluid, e.g., water into device 100. Additionally, fluid inlets 114 provide passageway for fluid (e.g., water) vapor from inside container 104 out into the circumambient non-soil environment of fertilizer device 100 and allow fluid equilibrium between container 104 and the circumambient non-soil environment.

[0041 ] Additionally, and optionally, the sieve form of cover 112 stops plant matter e.g., leaves and debris from entering fertilizer device 100 container 104. Additionally, and optionally and as explained in greater detail elsewhere herein, an external surface 128 of hydration indicator portion 108 comprises one or more protrusions 130. In some embodiments, protrusions 130 are light-dispersing protrusions. In some embodiments, protrusions 130 increase the surface area of external surface 128 of hydration indicator portion 108 to increase friction with the soil circumambient environment of device 100 and increase stability and anchoring of device 100 in the soil.

[0042] Reference is now made to Fig. 3, which is a cross section view simplified illustration of fertilizer device and its contents in a dry state in accordance with some embodiments of the present invention. As depicted in some embodiments, fertilizer holding portion 106 of fertilizer device 100 accommodates fertilizer 302 and super absorbent layer 304. In some embodiments, the superabsorbent polymer in layer 304 is coated with a water-permeable material or enclosed within a permeable capsule e.g., water beads. From this point on, the terms “superabsorbent polymer”, superabsorbent polymer layer 304 and super-absorbent beads 304 have the same meaning and are used interchangeably herein. In some embodiments, fertilizer-holding portion 106 also accommodates a water-soluble barrier layer 306 that forms a physical barrier between fertilizer-holding portion 106 and hydration indicator portion 108 and holds fertilizer 302 and super-absorbent beads 304 retains fertilizer-holding portion 106. In some embodiments, fertilizer 302 is placed at the bottommost aspect of fertilizer-holding portion 106 e.g., at the tip or base of the mushroom-shape stalk and is covered with a layer of super-absorbent beads 304. In some embodiments, in a pre-activation e.g., dry state, once cover 112 is placed over opening 110, a tip 350 of retainer 116 jutting inwards, towards fertilizer-holding portion 106 from the rim of opening 110, is urged against water-soluble barrier layer 306 to retain the three layers (fertilizer 302, super-absorbent beads 304, and water-soluble barrier layer 306) in place, while maintaining the layering pattern and order of the layers.

[0043] In some embodiments the device comprises a fertilizer. In some embodiments the fertilizer is selected from the group consisting of potassium nitrate, urea, monopotassium phosphate, ammonium sulfate, potassium sulfate, ammonium phosphate, a straight N fertilizer, a Calcium ammonium nitrate fertilizer (CAN fertilizer), an NPK fertilizer, an NP fertilizer, an NK fertilizer, a high N-NPK fertilizer and a combination thereof. In some embodiments the fertilizer comprises an NPK fertilizer. The term "NPK fertilizer" refers to fertilizer mixtures, which may comprise active inorganic macro nutrients comprising the chemical elements nitrogen (N), phosphorous (P) and potassium (K). The names and classification of NPK fertilizers are based on the relative amounts of chemicals comprising each of these elements in the mixture. For example, a fertilizer composition, which includes 20% nitrogenous compounds, such as amines, ureas and nitrates; 20% phosphorus compounds, such phosphorus pentoxide; and 20% potassium compounds, such AS potassium oxide and potash, would be classified as a 20-20-20 or 20:20:20 fertilizer. In case only some of the element are present in the fertilizer, any of the notations may be zero. Typically, NPK fertilizer are water soluble and heavier than water. As a result, aqueous solutions containing NPK fertilizers typically also have higher densities than that of water.

[0044] In some embodiments the fertilizer is provided in a water-soluble (by hydrolysis) granular form.

[0045] In some embodiments, the fertilizer is a slow-release fertilizer (SRFs), e.g., long-chain molecules synthesized by chemically combining a nitrogen-source molecule with an aldehyde - for example, urea formaldehyde or methyl urea. In some embodiments, the fertilizer is in granulated form. In some embodiments, the fertilizer is in bead form. [0046] In some embodiments, the fertilizer is configured to dissolve in a liquid e.g., water and provide a liquid phase (e.g., solution) fertilizer at a constant concentration, the release of which depends solely on a humidity gradient across apertures 120as explained in greater detail elsewhere herein. The small volume of the container 104 is conducive to accommodation of an amount of between 3 and 6 grams of a high-concentration fertilizer providing continuous fertilizer supply for a plant e.g., planted in a 30cm diameter planting pot over several months to a year. In some embodiments, the concentration of the fertilizer is predetermined in accordance to the type of plant to be fertilized and the size of pot in which the plant is planted.

[0047] In some embodiments, fertilizer devices 100 are pre-filled and marked for specific plants e.g., orchids, green leafed plants, flowers, vegetables, etc.

[0048] In some embodiments device 100 container 104 comprises a water-soluble material selected from the group consisting of pesticides, insecticides, fertilizers, disinfectants, plant protection agents, antibiotics, minerals, antibiotics, hormones and combinations thereof.

[0049] In some embodiments, a layer of beads 304 made of a super-absorbent material is layered over fertilizer layer 302. In some embodiments, layer 304 comprises a Super Absorbing Polymers (SAP) encapsulated in a polymer, e.g., water beads (Orbeez®) or hydro-gels. In some embodiments, the swelling end point (maximum absorbency) of the beads of super-absorbent bead layer 304 is at a diameter of between 2 and 1 mm or 5 and 9mm. In some embodiments, the beads of bead layer 304 are color-coded to differentiate between the various fertilizer designations of the fertilizer device 100. E.g., beads of a fertilizer device containing fertilizer for flowering plants may be red whereas beads of a fertilizer device containing fertilizer for leafy plants may be green and beads of a fertilizer device containing fertilizer for Lilach plants may be purple.

[0050] In some embodiments, water-soluble barrier layer 306 comprises a starch-based material e.g., Green Cell Foam™ manufactured by KTM™ Industries, Inc - 2325 Jarco Drive Holt, Michigan 48842. In some embodiments water-soluble barrier layer 306 comprises a porous e.g., sponge-form pad or disc. In some embodiments, water-soluble barrier layer 306 comprises other water-soluble materials e.g., PVa or any suitable water- soluble material. [0051] Reference is now made to Figs. 4A, 4B, 4C, 4D, 4E, 4F and 4G, which are cross section view simplified illustrations of operation of a fertilizer device in accordance with some embodiments of the present invention.

[0052] As shown in the exemplary embodiment depicted in Fig. 4A, fertilizer device 100 is in a in a pre-activation e.g., dry state, in which cover 112 is placed over opening 110, and tip 350 of retainer 116 jutting inwards is urged against water-soluble barrier layer 306 locking the three layers (fertilizer 302, super-absorbent beads 304 and water- soluble barrier layer 306) in place retaining the order of the layers. Fertilizer device 100 is deposited in a substrate 400 e.g., potting soil, tufa, artificial soil (e.g., beads or sponge) or any other substrate suitable for planting.

[0053] In some embodiments, liquid e.g., water is introduced into container 104 via inlets 114 in cover 112, as indicated by arrow 450. Alternatively, or additionally and optionally and as shown in Fig. 4B, water seeps into fertilizer-holding portion 106 of container 104 via apertures 120 in wall 102 driven by a humidity gradient across the apertures 120 between the humidity in the circumambient substrate 400 and the humidity inside container 104 as indicated by arrows 475. As depicted in Fig. 4C, water absorbed in water-soluble barrier layer 306 brings about dissolution of water-soluble barrier layer 306 and disintegration of the physical barrier between fertilizer-holding portion 106 and hydration indicator portion 108. This allows layer of super- absorbent beads 304, having absorbed water, to expand in a direction indicated by arrows 495 and fill hydration indicator portion 108 as illustrated in Fig. 4D. Further addition of water as indicated by arrow 450 brings about seepage of water from inside container 104 via apertures 120 into circumambient substrate 400. In some embodiments, layer 306 comprises an insoluble material in which case, an expansion of super-absorbent beads 304 urges against the barrier layer 306 pushing it into hydration indicator portion 108.

[0054] Figs. 4E and 4F illustrate a circumstance in which humidity in the circumambient substrate 400 is lower than the humidity inside container 104 leading to a humidity gradient across apertures 120 between the humidity in the circumambient substrate 400 and the humidity inside container 104. In some embodiments, the lower humidity is in both the soil and the non-soil circumambient substrate 400 leading to a humidity gradient between the humidity in the circumambient substrate 400 and the humidity inside container 104. The humidity gradient across apertures 120 between the non-soil circumambient substrate 400 leads to evaporation of water from container 104 via inlets 114 in cover 112 of the device 100 as indicated in Fig. 4F by arrows 435. [0055] In some embodiments, this condition brings about seepage of water from inside container 104 via apertures 120 out to circumambient substrate 400 as indicated by arrows 475. Further movement of water out of container 104 and into circumambient substrate 400 brings about drying and shrinkage of super-absorbent beads 304. The shrinkage of super-absorbent beads 304 restores the previous configuration of device 100 in which hydration indicator portion 108 of container 104 is empty of super-absorbent bead 304 which become once again disposed in fertilizer-holding portion 106 as shown in Fig. 4F.

[0056] In some embodiments, the fertilizer is configured to dissolve in a liquid e.g., water and provide a liquid phase (e.g., solution) fertilizer having a constant concentration. As shown in the diagram depicted in Fig. 4G, a water balance in container 104 is maintained between the fertilizer solution 402, the non-soil circumambient environment outside the container 404 e.g., evaporation into the atmosphere and the super-absorbent material 406.

[0057] In some embodiments, water input into container 104 is distributed between super-absorbent material 406 by absorption and a void inside container 104. The void in container 104 as referred to herein means any space inside container 104 not occupied by any of the layers (fertilizer layer 302, super-absorbent layer 306 and/or water-soluble layer 308). Dissolution of the fertilizer layer 302 into the water in the container void forms a fertilizer-water solution.

[0058] A difference in the humidity between the content of container 104 and the soil circumambient environment outside container 104 drives the solution (fertilizer and water), to seep out of container 104 and into the soil as indicated in Figure 4G by a thick arrow 410. This has no effect on the water balance inside container 104 and therefore the concentration of the fertilizer solution 402 remains constant.

[0059] Removal of water out of fertilizer solution 402 into the non-soil circumambient environment 404 e.g., by evaporation into the atmosphere, brings about reduction in the solution volume. This is followed by the drawing of water out of the super-absorbent material 406 back into the void created by the reduction in the volume of solution and shrinkage of the super-absorbent material and is mixed with the remaining solution in the container. This process, being continuous, maintains the concentration of the solution constant at all times.

[0060] As explained elsewhere herein, shrinkage of the super-absorbent material out of hydration indicator portion of container 104 brings about a change in or disappearance of color that indicates the need for replenishment 408 of water in the container 104. [0061] In summary, the amount of fertilizer released from container 104 is solely dependent on the humidity difference between the content of the device and the soil circumambient environment while the concentration of the solution remains constant at all times.

[0062] Reference is now made to Figs. 5 A, 5B, 5C, 5D and 5E, collectively referred to as Fig. 5, which are cross-section view simplified illustrations of operation of a fertilizer device in accordance with some embodiments of the present invention. In Fig. 5, super absorbent bead layer 304 has been omitted for simplicity of explanation. Fig. 5A depicts device 100 container 104 embedded in a substrate 400, such that fertilizer-holding portion 106 is below the surface of substrate 400 and at least a portion of hydration indicator portion 108 protrudes above the surface of substrate 400. In the exemplary embodiment depicted in Fig. 5 A, the contents of container 104 is in a steady state in which there is a humidity equilibrium between the contents of container 104 and circumambient substrate 400 indicated by double -headed arrows 550.

[0063] In some embodiments, and as shown in Fig. 5B, addition of water to container 104, as indicated by arrow 450 in Fig. 5B, brings about dissolution of fertilizer layer 302 into the water expressed in Fig. 5B as a reduction in the amount of fertilizer layer 302 and formation of a fertilizer solution at a predetermined fertilizer concentration in accordance with the type and quantity of the fertilizer in layer 302 and the size of container 104, which defines the maximum amount of water inside the container 104. [0064] Since the content of container 104 is relatively isolated from the circumambient substrate 400 concentration differences between liquid inside container 104 and circumambient substrate 400 bring about little to no osmosis through aperture 120 of wall 102 of container 104. However, as shown in Fig. 5B, drying of circumambient substrate 400 brings about higher humidity inside container 104 leading to a humidity gradient across apertures 120 between the higher humidity inside container 104 and the lower humidity in the circumambient substrate 400. In some embodiments, this humidity gradient drives water, carrying with it dissolved fertilizer, from inside container 104 via apertures 120 out to circumambient substrate 400 as indicated by arrows 575. This process continues up to re-establishment of an equilibrium depicted in Fig. 5C and a steady state between the inside of container 104 and the circumambient substrate 400 indicated by double-headed arrows 595.

[0065] Fig. 5D illustrates re-drying of circumambient substrate 400 leading to higher humidity inside container 104 leading to a humidity gradient across apertures 120 between the higher humidity inside container 104 and the lower humidity in the circumambient substrate 400 and a repeat of the process as described elsewhere herein to an equilibrium and a steady state between container 104 and circumambient substrate 400 smaller amount of fertilizer 302 in fertilizer-holding portion 106. This cycle is repeatable as long as there remains fertilizer in container 104, which may last for several months to a year. In circumstances in which the humidity in circumambient substrate 400 is equal to or greater than that inside container 104 e.g., during the winter when many plants are in a dormant state, no fertilizer is released from container 104.

[0066] A potential advantage of the fertilization process being water-dependent and water-driven is in that unlike in other systems in which the control of fertilizer release is based on a quantity of fertilizer to be released e.g., control -release fertilizer beads, the release of fertilizer layer 302 in container 104, being at a constant concentration inside container 104, is dependent solely on the water gradient between the content of container 104 and the soil and/or non-soil circumambient substrate 400 and therefore controlled by the water management of the plant fertilized by device 100. In some embodiments, control of the rate of release of the fertilizer is predetermined by the number and size of apertures 120 in wall 102 of container 104.

[0067] For example, during summer months there is increase evaporation from the soil circumambient substrate 400 as well as from device 100 itself. The addition of water to device 100 forms a humidity gradient as explained in greater detail elsewhere herein that leads to seepage of water and fertilizer from container 104 into soil circumambient substrate 400. However, in the winter, when plant growth is limited and there is less of a requirement for fertilizer, the device 100 is in humidity equilibrium with the humidity in circumambient substrate 400 forming a steady state in which no water seeps out of or into container 104 and no fertilizer is released either.

[0068] Reference is now made to Figs. 6A, 6B and 6C, which are side view and cross- section view simplified illustrations of a fertilizer device hydration indicator in accordance with some embodiments of the present invention. In the exemplary embodiment depicted in Fig. 6A, device 100 container 104 is embedded in a substrate 400, such that fertilizer-holding portion 106 is below the surface of substrate 400 and at least a portion of hydration indicator portion 108 protrudes above the surface of substrate 400.

[0069] In some embodiments, external surface 128 of hydration indicator portion 108 comprises one or more protrusions 130. In some embodiments, protrusions 130 form an integral part of external surface 128 of hydration indicator portion 108. In some embodiments, protrusions 130 are light-dispersing protrusions. In some embodiments, protrusions 130 increase the surface area of external surface 128 of hydration indicator portion 108 to increase friction with the soil circumambient environment of device 100 and increase stability and anchoring of device 100 in the soil.

[0070] As explained in detail elsewhere herein, super-absorbent beads 304 fill hydration indicator portion 108 completely, partially or not at all, depending on their hydration status. E.g., fully hydrated super-absorbent beads 304 at their maximum swelling ability fill hydration indicator portion 108 completely, whereas non -hydrated (dry) super-absorbent beads 304 at their non-swollen state remain disposed inside fertilizer— holding portion 106 and do not reach hydration indicator portion 108 at all. Partially hydrated super-absorbent beads 304 occupy hydration indicator portion 108 at varying levels of fill depending on their hydration level.

[0071] In dry conditions, super- absorbent beads 304 are in their non-hydrated (dry) state leaving hydration indicator portion 108 empty. As illustrated in Fig. 6B, which is a cross-section view of hydration indicator portion 108 as viewed from a direction indicated in Fig. 6A by an arrow 650, light entering hydration indicator portion 108 travels across in an uninterrupted manner as indicated by arrows 675. To a viewer viewing hydration indicator portion 108 from outside container 104, hydration indicator portion 108 appears empty or clear.

[0072] Once container 104 is filled with water, and super-absorbent beads 304 are mostly or fully hydrated, close or at their maximum swelling ability, beads 304 fill hydration indicator portion 108 completely. Light travelling through hydration indicator portion 108 is reflected off super-absorbent beads 304, pass through wall 102 of indicator portion 108, where it is dispersed by light-dispersing protrusions 130 in various directions indicated by arrows 695.

[0073] In some embodiments, super-absorbent beads 304 are color-coded to differentiate between the various fertilizer designations of the fertilizer device 100. E.g., beads of a fertilizer device containing fertilizer for flowering plants may be red whereas beads of a fertilizer device containing fertilizer for leafy plants may be green and beads of a fertilizer device containing fertilizer for Lilach plants may be purple. The color of super-absorbent beads 304 is therefore reflected and dispersed by light-dispersing protrusions 130. To a viewer viewing hydration indicator portion 108 from outside container 104, hydration indicator portion 108 appears to be colored in accordance with the color of super-absorbent beads 304.

[0074] Hence, the appearance of hydration indicator portion 108 provides an indication to a user as to the hydration status of the plant and plant soil circumambient environment 400. For example, a clear-appearing hydration indicator portion 108 suggests dry conditions indicating that watering and fertilizing is required. Adding water to device 100 container 104 e.g., via cover 112 begins the hydration and fertilization process of circumambient environment 400 as described in detail elsewhere herein. The appearance of color in hydration indicator portion 108 is indicative that no watering and/or fertilization is required.

[0075] In some embodiments and optionally, cover 112 retainer 116 is colored white to provide a background to the color reflected off super-absorbent beads 304. In this configuration, in a fully hydrated state, container 104 viewed directly from above appears to be white with a colorful ring surrounding the white-colored portion, whereas a side view of the container 104 reveals the color of super-absorbent beads 304, dispersed by light-dispersing protrusions 130. [0076] In accordance with some embodiments of the current invention there is provided a method of fertilizing a plant, the method comprising combining a solvent and a fertilizer in solid form and forming a fertilizer solution. In some embodiments, the solvent is water. In some embodiments, the method also comprises buffering between the fertilizer solution and a soil circumambient environment receiving a plant to be fertilized. In some embodiments, providing channels in the buffer layer so that to allow seepage of a liquid from one side of the buffer layer to another and forming a humidity gradient to drive the fertilizer solution via the channels in the buffer layer to the soil circumambient environment 400 receiving a plant to be fertilized. In some embodiments, the buffer layer is a wall 102 of a container 104 and the channels are apertures in the wall. In some embodiments, the fertilizer is as described in greater detail elsewhere herein.

[0077] In some embodiments, the method also includes providing color-coded super absorbent beads 304 indicative of a hydration status of the soil circumambient environment 400 receiving a plant to be fertilized. In some embodiments, the color-coded super-absorbent beads 304 are indicative of fertilizing requirement of the soil circumambient environment 400 receiving a plant to be fertilized.

[0078] Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0079] Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.

[0080] In the description and claims of the application, each of the words “comprise” “include” and “have”, and forms thereof, are not necessarily limited to members in a list with which the words may be associated. In addition, where there are inconsistencies between this application and any document incorporated by reference, it is hereby intended that the present application controls.

[0081 ] The descriptions of the various embodiments of the present invention have been presented for purposes of illustration but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.