PLANT GROWTH IMPROVEMENT FOR MODULAR PLANT SYSTEMS

Abstract: Improved growing pans (24) for aeration of modular plant units are provided comprising a network of air channels (10) in fluid communication with a plurality of aeration orifices (22) at the bottom surface of the pans (24). Optimum gaseous mixtures are forced up through the growing medium (14) to provide evenly distributed air pockets throughout plant root systems. Alternatively, gases may be suctioned out of the growing medium (14). This invention provides for soil aeration for all types of growing media, promoting stronger and deeper root growth. Circulation of air is provided, removing carbon dioxide, methane, hydrogen sulfide and other harmful gases from the root systems and surrounding plant environment.

Description: PLANT GROWTH IMPROVEMENT FOR MODULAR PLANT SYSTEMS This is a continuation-in-part of Serial No. 08/468,713 filed in the U.S. Patent and Trademark Office on June 6, 1995. FIELD OF THE INVENTION This invention is directed to improvements in transportable plant growing units. Aeration of modular growing pans and plant growing medium contained therein is provided. BACKGROUND OF INVENTION Turf and other plant growing systems are known wherein growing pans cooperate to form a natural plant surface for diverse environments, such as sports stadia. Maintenance and growth requires sufficient drainage and aeration techniques. Drainage techniques are disclosed in Ripley, et al. Re. No. 35,006 of U.S. Pat. No. 5,187,894, wherein integral pans comprise bottom areas with drainage orifices internally formed or drilled separately for adequate drainage of water under the surface. While these drainage orifices allow for some exchange of gas, they are insufficient to provide adequate aeration needed to control root and zone temperature which allows for the retardation of snow and ice accumulation and to keep plants from going dormant. In all-weather environments, freezing water may deform the growing pans upon expansion. Ripley et al. in Re. No. 35,006 of U.S. Pat. No. 5,187,894 disclose a lightweight expandable polymer growing medium in which freezing water deforms the polymers rather than the growing pans containing them. Sterrett et al. in U.S. Patent No. 4,067,716 disclose a growing medium comprising combusted bark particles with improved wetting characteristics. Plant growing media often require surface aeration. Conventional means of aeration for plants include surface aeration with hollow tines or coring for maintaining healthy root systems, and carefully selected artificial growing media which are less prone to dense packing than ordinary soil. These methods may be inadequate for aeration when heavy use can densely pack even expanded polymers. Moreover, surface aeration methods require manual labor and often produce unsightly plant and soil litter. There is a need to provide plant growing pans with a universal modification that will provide for improved aeration techniques which will thereby improve soil properties and promote healthier plants for use in nearly any type of plant growing medium, including ordinary soil. OBJECT OF THE INVENTION One object of this invention is to provide subsurface aeration of plant growth media in modular growing pans to promote the growth and maintenance of plants under select optimum conditions. A further object is to provide improved growing pans for plants which may eliminate the need for surface aeration and carefully selected growing media while attracting roots deeply into the soil, providing air circulation to remove potentially harmful gases, and providing adequate water drainage. A further object is to provide means to easily transport and install modified growing pans for use in the provision of plant surfaces in stadia, gardening, landscaping, and the like. These and other objectives will become apparent from a review of the instant specification and attendant claims. SUMMARY OF THE INVENTION In accordance with the present invention, growing pans are provided for improved ventilation of plant growing media and plants. Transportable growing units each comprise a growing pan adapted for containing plant growing medium together with plants, the growing pan comprising a bottom having a network of air channels defined therein, a plurality of sidewalls extending upwardly from the perimeter of the bottom and having a top edge, and a plurality of uniformly spaced aeration orifices comprising at least about 0.3% of the surface area of the bottom, the aeration orifices being in fluid communication with the air channels to allow for sufficient gas exchange. In another embodiment the orifices account for at least about 0.4% of the surface area of the bottom. In a preferred embodiment, the aeration orifices account for about 0.5% to about 4% of the surface area of the bottom, with 0.5% being most preferred. In other embodiments of the present invention methods are disclosed for improving the growth of plants comprising providing a growing pan adapted for containing plant growing medium together with plants. The growing pan has a network of air channels in fluid communication with a plurality of uniformly spaced aeration orifices through which pressurized gas is forced to aerate the growing medium and plants. In order to provide sufficient aeration means are provided for cooperating with the orifices for forcing gas through the growing medium and plants. The growing pan is capable of transportation and modular installation in accordance with previously described systems for modular plant growing, i.e., Ripley et al.; U.S. Pats. No. 5,187,894; Re. No. 35,006 and 5,467,555, each of which is incorporated herein by reference. The growing pans cooperate with eachother to provide plant surfaces in stadia, gardening, landscaping or the like. Although the pans may interlock, this is not a necessary feature. Modification of plant growing pans may be at either a remote site of plant growth and maintenance or at the primary location of plant use, depending on frequency of rotation between the two locations, degree of soil settling that may occur from activity on plant or turf surface, and ease of modifying growing pans at the site. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 depicts a growing pan with aeration and drainage orifices and air channels for aeration. An embodiment is shown having stretchers which raise the pan from the underlying surface. Figure 2 depicts a cross section of growing pan containing growing medium and plants with orifices for aeration and water drainage. Figure 3 depicts, in perspective, a partial array of growing units showing air channels and an end piece for closing off the network of air channels at a periphery of the assembly or array. Figure 4 depicts a top view of a growing pan. PREFERRED EMBODIMENTS It has been determined that soil aeration is critical for healthy plant growth and maintenance. This is especially true for modular turf and other plant units which risk suffering dense soil packing from high-impact use. In accordance with the present invention, it is now possible to allow gaseous mixtures, such as those containing harmful gases, to flow out of the growing medium through the bottom of a plant growing pan and to introduce advantageous air evenly throughout the growing medium. In the present invention a growing pan for containing plant growing medium is provided comprising a bottom having a network of air channels defined therein, a plurality of sidewalls extending upwardly from the perimeter of the bottom and having a top edge, and a plurality of uniformly spaced aeration orifices comprising at least about 0.3% of the surface area of the bottom, the aeration orifices being in fluid communication with the air channels. In other embodiments, the aeration orifices comprise at least about 0.4% of the surface area of the bottom. In preferred embodiments the aeration orifices comprise from about 0.5%) to about 4% of the surface area of the bottom, with 0.5% being most preferred. In some embodiments, the present invention provides methods for improving the growth of plants whereby growing pans adapted for containing plant growing medium together with plants are provided. The growing pans have defined therein a network of air channels in fluid communication with a plurality of uniformly spaced aeration orifices. Pressurized gas is forced through the orifices to aerate the growing medium and plants. Referring to the drawings, a network of air channels in 10 and between 18 growing pans 24 is in fluid communication with aeration orifices 22 at the bottom of the growing pans. Drainage holes 30 are also shown. The bottom of the growing pan may also have stretchers 20 which raise the turf unit from an underlying surface to permit improved water drainage and allow for improved aeration of the entire growing medium 14. The stretchers also provide assistance in the transportation of the units and can be modified to level an entire modular plant growing surface with uneven subsurfaces. Figure 3 shows one end piece 26 which cooperates with the geometry of the growing pans 24 to effectively block the air channels at a periphery of an assemblage of pans. This maintains pressure in the air channels 10, 18. As will be apparent, it is preferred to block the entire periphery in order to improve gas throughput through the growing pans. Where it is desirable to force positively or negatively pressurized air through the growing medium, it is necessary to provide a suitable fitting for introducing the pressurized gas into the network of air channels. Such fittings, such as screw fittings, nipples, friction fittings and the like are commonplace, and well known to those skilled in the art. The means for supplying pressurized air or other gas can be any conventional source such as a vacuum pump, compressor, blower, fan or other means. It is also conventional to add components to a gas mixture, e.g., air, to increase the percentage of the composition attributable to particular gasses, e.g., carbon dioxide or oxygen. The growing pans may preferably comprise a gas-permeable mesh or other liner to preclude soil seepage through water drainage orifices, while allowing removal of carbon dioxide, methane, hydrogen sulfide, and other potentially harmful gasses from the plant's environment. This helps to further attract roots down into the soil to make the turfgrass or other plants more resistant to disease, wear, drought damage and saturation damage. In one embodiment of the invention, growing pans are provided with means of aeration at a remote location analogous to a green house specially adapted for their growth and maintenance. Plants benefit from the particularized conditions optimum for plant development for the maximum period of time prior to being exposed to activity conditions. Additionally, varying plant or plant units may be substituted in order to maintain the actual primary use location in optimum condition. Alternatively, modular plant growing pans at the primary use location are aerated to eliminate the need for frequent replacement by plant units from the remote location. Gaseous mixtures forced through the soil rise to the environment around the stem and leaves of the plant, where photosynthesis and respiration primarily occur. The mixtures may be optimized for nurturing modular plant units. For example, when plants are exposed to light, photosynthesis generally exceeds respiration. Plants consume more carbon dioxide than they release and release more oxygen than they consume during this period. Gaseous mixtures introduced when plants are exposed to light may, preferably, be enhanced in carbon dioxide and depleted in oxygen relative to air in order to promote photosynthesis. For example, when plants are exposed to light, said gas comprise: from about 15 to 20% by volume oxygen; from about 80 to 85% nitrogen; from about 0.03 to .1% carbon dioxide. Similarly, respiration predominates while plants are in darkness, and plants can benefit from gaseous mixtures enhanced in oxygen and depleted in carbon dioxide to drive this process. While plants are in darkness, the gas may preferably comprise: from about 20 to 30% by volume oxygen; from about 70 to 80% nitrogen; from about 0 to 0.03% carbon dioxide. In urban areas, where plants are generally exposed to higher levels of carbon dioxide and other potentially harmful gases, it is preferred to deplete the gaseous mixture of carbon dioxide relative to the background air plants normally are exposed to. It will be appreciated that when pluralities of growing units are assembled together, a relatively large surface is formed. The air channels in and among the units preferably cooperate to form a network of such channels. In some embodiments, the channels are provided with a source of a pressurized air mixture such as provided by blowers or the like, or with a source for introducing negative pressure, such as vacuum pump. The periphery of an assemblage of growing pans may be closed off in any consistent manner to cause the air to be forced into the pans and through the growing medium therein. Such closures may be through application of a wall, film or other barrier at such periphery or in any other convenient way. The pressure, frequency, and duration of subsurface aeration are optimized for the type of plant, growing medium and degree of soil packing which may occur from use. Growing media with a high degree of expandable polymers will require less aeration than ordinary soil. Plant roots may strengthen in response to frequent aeration and the resulting disturbance of growing medium. The force and duration of aeration should be adjusted according to the degree of beneficial response for each plant. For example, in some embodiments this invention claims a range of net gas aeration pressures to be forced through the growing medium of from about 1 to 100 psi. Gas may be forced through the growing medium continuously, for one hour beginning every other hour, for one hour during each period of plant exposure to light or darkness, or as adjusted for the most beneficial plant response. As is apparent, turf surfaces, e.g. for athletic events and gardens may be built from a plurality of growing pans connected together along with preferred soil pieces such that the network of air channels can be pressurized with gas. Improved growth results. It is preferred that plant growing media comprise an artificial soil having a relatively light weight for transportation. The soil may include an expanded polymer with an extremely light specific gravity selected to be substantially inert with respect to plant growth chemistry. It is also preferred to provide modular, transportable plant units designed to cooperate with each other to facilitate the elaboration of substantially continuous plant surfaces for athletics, decoration and other uses. Those skilled in the art will appreciate that numerous changes and modifications can be made to the preferred embodiments of the invention and that such changes and modifications can be made without departing from the spirit of the invention. It is therefore intended that the appended claims cover all such equivalent variations as fall within the true spirit and scope of the invention.

Claims: What is claimed is: 1. A growing pan for containing plant growing medium comprising: a bottom having a network of air channels defined therein; a plurality of sidewalls extending upwardly from the perimeter of said bottom and having a top edge; a plurality of uniformly spaced aeration orifices comprising at least about 0.3%) of the surface area of said bottom, said aeration orifices being in fluid communication with said air channels. 2. The growing pan of claim 1 wherein said aeration orifices comprise at least about 0.4% said surface area. 3. The growing pan of claim 1 wherein said aeration orifices comprise from about 0.5% to about 4% of said surface area. 4. The growing pan of claim 1 wherein said aeration orifices comprise about 0.5%) of said surface area. 5. A method for improving the growth of plants comprising: providing a growing pan adapted for containing plant growing medium together with said plants; providing said growing pan with a network of air channels in fluid communication with a plurality of uniformly spaced aeration orifices; and forcing pressurized gas through said orifices to aerate said growing medium and plants. 6. The method of claim 5 wherein said gas is forced through said growing medium by applying a positive pressure to said aeration orifices. 7. The method of claim 5 wherein said gas is forced through said growing medium by applying a negative pressure to said aeration orifices. 8. The method of claim 6 wherein said gas is forced through said growing medium while said plants are exposed to light, said gas comprising: from about 15 to about 20% by volume oxygen; from about 80 to about 85% by volume nitrogen; from about 0.03 to about 0.1% by volume carbon dioxide. 9. The method of claim 6 wherein said gas is forced through said growing medium while said plants are exposed to darkness, said gas comprising: from about 20 to about 30% by volume oxygen; from about 70 to about 80% by volume nitrogen; from about 0 to about 0.03% by volume carbon dioxide. 10. The method of claim 5 wherein said gas is forced through said growing medium at a net pressure over ambient of from about 1 to 100 psi. 11. The method of claim 5 wherein said gas is forced through said growing medium substantially continuously. 12. The method of claim 5 wherein said gas is forced through said growing medium for 1 hour out of every 2 hours. 13. A turf surface or garden comprising a plurality of plant growing units in accordance with claim 1 further comprising means for supplying pressurized gas through the plurality of orifices.

Inventors: CATALDO STEPHEN A, RIPLEY THOMAS J SR, SCOTT CHRISTOPHER, CATALDO, STEPHEN, A., RIPLEY, THOMAS, J., SR., SCOTT, CHRISTOPHER
Applicants: GREENTECH INC, GREENTECH, INC.
Application year: 2000
Main classification: A01N
IPC codes: A01G1, A01G7, A01G9