Hydration maintenance apparatus and method

A material for maintaining hydration in plants, whether potted or in natural soils may include a substrate treated with a binder, securing a layer of hydrating particles thereto. Typical binders may include lignicite, or other naturally occurring materials such as sugars, molasses, corn syrup, gelatin, or the like. A byproduct of wood, lignicite has been found to be very effective. Various materials can serve as a hydrating, particulate coating. Polyacrylamide has been found to serve well and provide relief from the stress of dehydration that normally occurs in plants between waterings.

BACKGROUND

1. The Field of the Invention

This invention relates to horticulture and, more particularly, to novel systems and methods for maintaining hydration of plants.

2. The Background Art

Different types of soils perform their functions differently. In particular, rocky soils, sandy soils and the like tend to pass water too freely. Likewise clay soils tend to hold water, but yet not permit the water to distribute therethroughout. Typically, organic soils having substantial amounts of loam formed by organic matter such as leaves, other foliage, decaying plant matter, and the like provide better absorption and holding of water.

In general, soil may be improved on a small scale by addition of organic matter such as peat moss. On a large scale, soils are typically improved by growing and plowing under certain plants selected for their addition of organic matter. Likewise, waste materials from corrals, grain stalks (straw) and the like may be plowed into tracts of land in order to improve their organic content and their capacity to hold water for use by plants.

Gelatin is a naturally occurring polymer. Gelatin binds with water to form a “gel.” The existence of naturally occurring polymers such as gelatin has been augmented by the development of synthetic polymers. One such polymer is polyacrylamide. Polyacrylamide (PAM) and other similar gels have been used for different types of binding processes. For example, a gel, when wet, may be easily formed, and when dry may become something of a glue or binder. Likewise, gels typically are formed of long polymers and thus are often durable in the face of erosive actions such as water running over them. Accordingly, gels such as PAM have been used to treat surfaces of ground in order to minimize erosion by the passing of water thereover.

Horticulture is the culture of plants. Plants rely on water as a transport mechanism in order to draw nutrients from the ground into the plants through the roots and into the stems, leaves, and so forth. Likewise, water acts as a transpiration cooling mechanism by evaporation out through the leaves and other foliage of a plant.

Thus, the health of plants depends upon access to water. Many parts of the United States, and even indoor plant locations such as malls, homes, offices, and the like, receive little or no rainfall. Irrigation or periodic watering by some mechanism is often required. In such situations, plants may dwell for an extended period without additional water. Organic soils improve the water holding capacity around such plants. Nevertheless, evaporation and periodic watering may still combine to put stress on plants.

It would be an advance in the art to provide a mechanism whereby to automatically store within a soil, such as near a plant root, near a rootball of a plant, within a pot or indoor planter, or the like, a mechanism to absorb water, releasing it over time while resisting evaporation.

BRIEF SUMMARY OF THE INVENTION

In view of the foregoing, in accordance with the invention as embodied and broadly described herein, a method and apparatus are disclosed in one embodiment of the present invention as including a substrate, which may be formed of sand, rock, or organic material, provided with a binder to temporarily or permanently secure a hydrating polymer such as polyacrylamide (PAM) in proximity to the substrate. In certain embodiments, such as where a potted plant may have a transparent vessel or pot in which it is held, pigment may be added to the polymer, to the binder, or to the surface of the substrate by any suitable mechanism. Thus, the hydration maintenance material may be configured as a decorative or identifying element on its own or for a potted plant, for example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIG. 1, a material10in accordance with the invention may include a substrate12formed of a suitable material for placement in the vicinity of a root system of a plant. For example, a substrate may be a particle of sand. In certain embodiments, even gravel or rock in a potting environment may operate as a substrate. In some embodiments, a substrate may be formed of organic or inorganic material. Nevertheless, it has been found effective to use sand as a substrate12inasmuch as it is submersible in water and will not float as many organic materials will when dry. Likewise, the sand as substrate12is comminuted to such a small size that interstices between individual grains of the sand substrate12provide ample space and minimum distance for water to surround each of the substrate12particles.

In the illustrated embodiment, a binder14may be distributed as a comparatively thin layer on the surface of the substrate12. Typical materials for binders may include both temporary and permanent binders14. Temporary binders may be sugar-based or other water soluble materials. For example, corn syrup, molasses, and the like may form temporary binders. In the presence of water, such material may ultimately dissolve. Nevetheless, so long as the substrate12is not turned, mixed, or otherwise disturbed significantly, any other materials supported by the binder14would not be expected to dislocate.

Otherwise, certain naturally or synthetically occurring polymers may also be used as a binder14. Lignicite may be used as a binder14. Lignicite is a byproduct of wood, and provides material having good adhesive properties, and substantial permanence as a binder14on a substrate12.

Other polymers may be used to form a binder14. For example, various materials used as glues, including mucilage, gelatin, other water soluble polymers including, for example, Elmer's™ glue, and the like may also operate as binders14to bind materials to a substrate12.

In certain embodiments, the substrate12may be used in soils in outdoor environments. In other situations, the substrate12may be implemented in indoor pots and planters. In other embodiments, the substrate12may be used as a filler material in planters or pots having transparent or translucent walls. In such embodiments, a pigment16may be added. Likewise, even if the substrate12and its contents bound thereto by the binder14are not to be seen, they may be pigmented with an appropriate pigment16simply for the purpose of identification during selection, scale, or installation. Accordingly, a pigment16may be provided.

The pigment16may be implemented in any of several manners. For example, the substrate12may have pigment16applied prior to the application of the binder14. In alternative embodiments, the pigment16may actually be included in the binder14, which becomes a pigmented coating on the substrate12. In yet other embodiments, the pigments16may be added to a hydration particle18either as a pigment16mixed therein, or as a pigment16applied as a coating thereto. Thus the location of the pigment16in the Figures is schematic and may take alternative location or application method.

Particles18of a hydrophilic material may be bonded to the substrate12by the binder14. Particles may be sized to substantially coat or periodically coat the substrate12.

In certain embodiments, the hydrophilic material18may be a powdered polymeric material18such as polyacrylamide. In other embodiments, the particles18may actually be organic material having capillary action to readily absorb and hold water. In one presently contemplated embodiment of an apparatus in accordance with the invention, the particles18may be powdered polymeric material in a dehydrated state, and having a capacity to absorb water, typically many times the weight of a particular particle18.

The substrate12, in certain embodiments, may be sand. The sand will typically be cleaned and washed to remove dust and organic material that may inhibit the binder14from being effective. Likewise, the substrate12may be sized of any suitable size. For example, sand particles may range from much less than a millimeter in effective diameter or distance thereacross to approximately two millimeters across. Very coarse sands may have even larger effective diameters. Likewise, in certain embodiments, gravel of various sizes may operate as a substrate12. However in one presently contemplated embodiment, washed and dried sand such as is used in construction, such as in concrete, has been found to be suitable. Fine sands such as masonry sands tend to be smaller, and also can function suitably in accordance with the invention.

Accordingly, the distance across each particle18may be selected to provide an effective coating of powdered particles18on the substrate12. In one presently contemplated embodiment, the effective diameter of the particles18may be from about a 30 mesh size to about a 100 mesh size. For example, a sieve system for classifying particles has various mesh sizes. A size of about 30 mesh, able to pass through a 30 mesh sieve, (i.e., about 0.6 mm) has been found suitable. Likewise, powdering the particles18to a size sufficiently small to pass through a 100 mesh (i.e., about 0.015 mm) sieve is also satisfactory. A mesh size of from about 50 mesh to about 75 mesh is an appropriate material to obtain excellent adhesion of particles18in the binder14, with a suitable size of the particles18to absorb significant liquid at the surface of the substrate12.

As a practical matter, about half the volume of a container containing a substrate12as particulate matter will be space, interstices between the granules of the substrate12. One advantage of using materials such as sand as the substrate12is that a coating of the particles18may provide a substantial volume of water once the particles18are fully saturated. By contrast, where the size of the particles18is too many orders of magnitude smaller than the effective diameter or size of the substrate particles12, less of the space between the substrate particles12is effectively used for storing water. Thus, sand as a substrate12coated by particles18of a hydrophilic material such as a polymer will provide substantial space between the substrate particles12to hold water-laden particles18.

The diameter of the particles18, or the effective diameter thereof, is typically within about an order of magnitude (e.g., 10×) smaller than the effective diameter of the particles of the substrate12. This order of magnitude may be changed. For example, the order of magnitude difference less than about 1 order of magnitude (i.e., 10×) may still be effective. Similarly, an order of magnitude difference of 2 (i.e., 100×) may also function.

However, with particles18too much smaller than an order of magnitude smaller than the effective diameter of the substrate12, the interstitial space may not be as effectively used. Likewise, with an effective diameter of particles18near or larger than about 1 order of magnitude smaller than the size of the particles of the substrate12, binding may be less effective and the particles18may interfere more with the substrate itself as well as the flow of water through the interstitial spaces needed in order to properly hydrate a material10.

Referring toFIG. 2, an embodiment of a process for formulating the material10may involve cleaning22the material of the substrate12. Likewise, the material of the substrate12may be dried24to make it more effective in receiving a binder14. The material of the substrate12may then be blended26.

One embodiment, a ribbon blender provides an effective mechanism to perform continuous blending as the binder14is added28. Other types of mixers, such as rotary mixers, and the like may be used. However, a ribbon blender provides a blending26that is effective to distribute binder14as it is added28.

For example, if an individual particle of the substrate12receives too much binder14, and thus begins to agglomerate with other particles of the substrate12, a ribbon binder will tend to separate the particles as a natural consequences of its shearing and drawing action during blending26.

As the binder14is added28to the mixture being blended26, the individual particles of the substrate12will be substantially evenly coated. At this stage, the binder14may also be heated in order to reduce its viscosity and improve blending. Likewise, the material of the substrate12or the environment of the blending26may be heated in order to improve the evenness of the distribution of the binder14on the surfaces of the substrate12materials or particles12.

Blending26of the binder14into the material of the substrate12is complete when coating is substantially even, and the texture of the material10has an ability to clump, yet is easily crumbled and broken into individual particles. At that point, addition30of the hydrophilic particles18may be accomplished.

For example, adding30the particles18as a powder into the blending26is a naturally stable process. Typically the particles18attach to the binder14of the substrate12particles, thus removing from activity that location. Accordingly, other particles18rather than agglomerating with their own type of material will continue to tumble in the blending26until exposed to a suitable location of binder14of the substrate12. Thus, the adding30of the particles18or powder18of hydrophilic material will tend to be a naturally stable process providing a substantially even coating on all the particles of the substrate12.

Just as marshmallows are dusted with corn starch, rendering them no longer tacky with respect to one another, the material10formulated by the process20are dusted with particles18and will pour freely. Accordingly, distribution32may be conducted in a variety of ways and may include one or several processes. For example, distribution may include marketing distribution from packaging after completion of blending26, shipping to distributers and retailers, and purchase and application by users.

An important part of distribution32is the deployment of the material10around the roots of a plant. In one embodiment of an apparatus and method in accordance with the invention, the material10may be poured, as if it were simply sand12or other substrate12alone. Since the powder18or particles18have substantially occupied the binder14, the material10will not bind to itself, but will readily pour as the initial substrate material12will.

Referring toFIG. 3, in one embodiment of an installation34, distribution32may include pouring a layer of the material10near a plant. In the illustration ofFIG. 3, the process34or installation34may include a cavity36formed in the ground, or by a container such as a pot, planter, or the like. In the illustrated embodiment, the cavity36may have a surrounding environment37such as the ground. A potting mixture38or potting soil38may fill a portion of the cavity36.

For example, one conventional mixture of horticulturists may include a mixture of peat moss or compost along with other drainage materials. For example, gravel, sand, vermiculite, perlite, or the like may be mixed with an organic material such as peat moss or compost in order to provide drainage in addition to the moisture capacity of the organic material.

The material10in accordance with the invention may be disposed in a layer40poured around a rootball42of a plant44. Accordingly, the layer40may provide to the rootball42, or to individual roots a surrounding environment40having both ease of water transport or drainage through the substrate12(e.g., sand, etc.) while also having the particles18of hydrophilic material to absorb and maintain water within the interstitial spaces between the substrate12particles.

Thus, the layer40provides a reservoir within the cavity36of a material10engineered to maintain a high degree of hydration (e.g., water in a gel) that will not drain into the environment37, nor be readily evaporated out. To this end, a top dressing46or a top layer46may be laid down on top of the layer40in order to provide some protection against evaporation from heat, sun, air, and the like. Thus, the top layer46may be formed of the same potting soil or other material of the layer38below the plant44and the rootball42. Various suitable top layers46exist and are known in the horticulture arts.

For example, mulches, wood chips, synthetic materials, plastic sealing, and the like may be used as a covering layer46. Inhibiting heat transfer and excessive access to air and heat may assist in reducing evaporation from the layer40of the material10.

Referring toFIG. 4, an alternative embodiment of an installation34may include the cavity36and an environment37as discussed above. In the embodiment ofFIG. 4, the rootball42may be surrounded by a distributed mixture48or fill48that includes the material10mixed into another potting soil mixture. For example, in the embodiment ofFIG. 4, a potting soil mixture of any suitable combination of materials (e.g., selections from vermiculite, perlite, sand, peat moss, compost, soil, gravel, or the like) may be mixed with the material10throughout. A top layer46forming a suitable dressing to minimize evaporation from heat or wind may still serve well.

The material10may typically include from about 1 percent to about 20 percent of a hydrophilic material18or particles18. The particles18may be formed of a naturally occurring material, such as a cellulose, gelatin, organic material, or the like.

In one embodiment, a synthetic gel, such as polyacrylamide may be used for the particles18, in a ratio of from about 1 to about 20 percent particles18compared to the weight of the substrate12. In experiments, a range of from about 5 to about 10 percent has been found to be the most effective for the amount particles18.

Sizes of particles18may range from about 20 mesh to smaller than 100 mesh. Particles18of from about 50 to about 75 mesh have been found most effective.

The binder14may typically be in the range of from about in ¼ percent to about 3 percent of the weight of the substrate12. A range of from about ¾ percent to about 1½ percent has been found to work best. That is, with a binder such as lignicite, ¼ of 1 percent has been found not to provide as reliable binding of particles18to the substrate12. Meanwhile, a ratio of higher than about 3 percent by weight of binder14to the amount of a substrate12, such as sand, when using lignicite as the binder14, tends to provide too much agglomeration. The pouring ability of the material10is inhibited as well as the blending26, due to agglomeration. Other binders also operate, including several smaller molecules that are water soluble. For example, glues, gelatins, sugars, molasses, and the like may be used as a binder14.

One substantial advantage for the material10in accordance with the present invention is that the material remains flowable as a sand-like material10into the area of roots and under a rootball or around the individual open roots of plants being transplanted. Thus, handling and application is simple, and the ability of granular material10to flow under and around small interstices between roots or between potting materials provides for a very effective application.

Certain experiments were conducted using the material10in accordance with the present invention. For example, in one experiment various sizes of planting pots were used ranging in size from one quart to one gallon, two gallons, and five gallons. Various plants were tested including geraniums, hibiscus, and Indian hawthorn.

In one experiment, a five gallon potting container was half filled with a potting soil mixture of conventional type. Approximately one liter of the material10was added as a layer on top of the potting soil. Three geraniums plants where then planted in the material10. And the remainder of the pot was filled with a potting soil mixture.

The pot was placed where it could drain and was watered liberally with the excess water running out of the drainage apertures in the pot. Four such pots were set up, each having three geranium plants. Four additional pots were set up without using material10in a layer40around the roots of the plants. All plants were planted and all pots were prepared on the same day. The same amount of water was applied to each of the pots.

After 10 days, the untreated plants lacking the material10in the extra layer40of the material10to hold the water appeared to be extremely stressed. In fact, the plants stressed sufficiently that after 15 days they appeared dead.

Plants potted in the layer40of the hydrated material10still appeared healthy after 10 days and after 15 days. At 35 days after watering, the plants in the treated pots containing the layer40of hydrating material10began to appear stressed. Upon watering, they responded well and returned to full hydration and health. The plants in the untreated pots did not recover.

Another test used hibiscus plants with four pots treated with the layer40of a hydrating material10and four pots untreated. All pots were the same size. The watering process was the same. Thus, as with the geranium experiment, all pots were watered equally.

After 15 days the hibiscus plants that had not been treated with the extra layer40of the hydrating material10appeared very stressed. After 20 days, the plants in the untreated plots were turning brown.

In contrast, hibiscus plants in the treated pots having an extra layer40of hydrating material10appeared healthy after 15 days and even out to 22 days, when the hibiscus plants in the untreated plots were in the browning stages of dying.

After 38 days, the hibiscus plants in the treated pots began to show stress. Water was provided to plants at 38 days. The untreated pots were watered the same as the treated pots. Plants in the untreated pots did not respond. The plants in the treated pots responded well and continued living healthily upon the watering at 38 days.

In one experiment, an Indian hawthorn was planted in the ground. About a liter of the material10was laid about the roots in a layer40as described hereinabove. In this instance, the experiment was conducted in an environment of natural ground. The Indian hawthorn plants were placed in holes approximately 18 inches across by about 15 inches deep. In each instance, the hole36prepared for the plant was partially filled with a soil and wetted. Two plants were placed in holes treated with approximately 1 liter of the material10, each. A control was created by planting two additional Indian hawthorns using each step the same, in preparation of the hole, placement of the soil in the hole, and watering of the soil and the plants. In the control, none of the material10was used.

No further water was applied. After 20 days, the untreated shrubs appeared to be dry with some stress. After 33 days, the plants in the untreated holes were dead. Meanwhile, the treated shrubs remained healthy throughout.

In another experiment, the foregoing experiment was repeated using two additional Indian hawthorn plants and treating the soil with a layer40containing about 1½ liters of the hydrating materials10near the roots. In that experiment, after 20 days, the shrubs appeared healthy. At 33 days, the shrubs began to show a minimal amount of stress. At 40 days, the stressed plants were watered and responded well, returning to health and continued life.

In all of the foregoing experiment series, the particles18were of polyacrylamide, and the substrate12was sand. The polyacrylamide constituted approximately 5 percent by weight of the overall material10. The particle size18was approximately a 60 mesh granularity.