AU717514B2 - Plant growing apparatus - Google Patents

Description

1

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT PLANT GROWING APPARATUS THE FOLLOWING STATEMENT IS A FULL DESCRIPTION OF THIS INVENTION, INCLUDING THE BEST METHOD OF PERFORMING IT KNOWN TO ME:- The present invention relates to a unit for the growth of plants. In particular, the 15 invention relates to several aspects of a new plant growing unit which enhance its suitability as a small-scale, indoor or patio installation.

*o There is disclosed herein plant growing apparatus including an open top sump for containing a plant nutrient solution, a growing tray for supporting a plurality of plants 20 and having a floor with a depressed portion adapted to contain water conditioning :means, said growing tray being supported on and substantially covering the sump, means for pumping the solution from the sump and contacting it with the plants in the °growing tray and drain means returning to the sump.

go Preferably the plant growing apparatus includes means for aerating the solution before contacting it with the plants.

Preferably said aerating means comprises means for swirling the solution in contact with air.

Preferably said aerating means includes an outlet from a top bowl.

Preferably at least part of the solution is passed over the surface of a filter in contact with air.

Preferably the depressed portion has a cover adapted to support plants.

Preferably said cover allows passage of light into said depressed portion.

Preferably at least a part of said depressed portion is adapted to be permanently flooded.

Preferably said flooded part of the depressed portion is adapted to contain aquatic plants.

A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings wherein: Fig. 1 is a schematic elevational cross-section of the device; Fig. 2 is a plan view of the growing tray; ooeo0 Fig. 3 is a perspective view of the growing tray; oFig. 4 is a perspective view of a dish adapted to fit inside the channel in the floor; Figs. SA and 5B are elevations of two different drainage devices which may be employed; and Fig. 6 is an elevational section of the aerating outlet of the top bowl.

oo 0 *o 0 oe...0 -3- With reference to Figs. 1 and 2, the unit generally consists of a sump 10, a growing tray 12 fitted on and supported by the sump, a top fluid distribution and growing bowl 14 and a covered nutrient container The sump contains a suitable level of a plant nutrient fluid 16 to cover the inlet of submersible pump 18, which is connected by hose 20 to a fluid outlet arrangement mounted above bowl 14. The outlet arrangement includes an upwardly directed nozzle 22 with a ball 24 which causes the formation of a mist or spray to humidify the environment in the region of the plant foliage, reducing transpiration losses in the plants. Fluid also travels over and through a filter oeoo 15 26 which removes impurities from the fluid, and falls into the bottom of the bowl 14. After a period of use, the filter may also support a colony of moss.

Contact of the water with this moss has been found to be beneficial to the water quality.

The top bowl 14 may be filled to a desired level with support medium, and has been found to be suitable for :i the growing of plants directly from seed, rather than requiring a separate seeding operation as usually 25 necessary with prior art hydroponics units.

The fluid level in the bowl rises until it reaches one or more outlets 28 in the side of the bowl. This arrangement is obscured in Fig. 1 but shown in more detail in Fig. 6. Shields 62 allow water to pass to the outlets but hold back the support media and any other large debris. The inner surface of the top bowl side wall 64 has an inwardly extending shoulder 66, through which a vertical outlet tube 68 extends, screwing into engagement to allow height adjustment.

The top of the outlet tube has a series of fine vertical slots 70 which act to strain out debris. It 'a1 -4has been found that the action of water flowing into the outlet tubes results in a swirling action, causing mixing of air and water. This aerates the fluid to be contacted with the plant roots, which is very important for healthy and vigorous growth of the plants.

Beneath the top bowl, the unit may have a nutrient container 15 which may contain fertiliser such as manure. Water flows onto the lid 15a of this container from the top bowl, onto the nutrient container then overflowing between the container and lid into the growing tray. The nutrient container is thus at all time full of water, reducing emission of 0000 15 odour. The nutrients from the manure are gradually absorbed into the nutrient solution circulating through the unit. In the case where it is desired to run the unit purely as a hydroponic system, without organic fertiliser, the nutrient container can be 20 filled with a filtration medium or omitted entirely.

00 0 Referring to Figs. 1 to 4, the floor 32 of the growing tray is capable of supporting a number of plants in pots (not shown), arranged about the centrally disposed top bowl 14. The floor may also contain small sockets 37 for insertion of upright stakes (not shown), for supporting the plants as they grow taller.

The unit is suitable for either natural or hydroponic plant growing. For hydroponic use, the planting pots may be filled with a hydroponic media such as rockwool or expanded clay, supplying support only to the roots of the plants and the remainder of the plants nutritional needs being met by nutrient solutions.

For natural plant growing, soil may be used.

An important aspect of the present invention is the U-shaped channel 38 in the floor of the growing tray. This channel is preferably covered by a transparent cover 40, thus forming an enclosed zone below the level of the floor. At least part of the channel is adapted to be permanently flooded. This may be achieved by having the channel below the level of the two drainage points drainage point 42 above the floor of the tray and the drainage tube 43 in the channel.

Alternatively, or additionally, the channel may be fitted with a dish 45, shown in Fig. 4, having side walls which retain a desired water level in the dish. The flooded channel portion is adapted to contain aquatic plants which serve to condition and aerate the fluid in the unit, improving plant health and growth. Alternatively, or in addition, decomposing organic matter can be placed in the channel to provide a source of organic fertilizer for the system. The inventor has found that, as the organic matter :4 is permanently covered with water, there is little or no odour.

0 The cover 40 serves to help support pots and to retain any debris within the flooded zone and thus reduce blockage of tubes and pumps in the system. As the cover is transparent, light can penetrate to allow the growth of the aquatic plants. From observation, it also appears that further mixing of air with the fluid occurs within the enclosed space.

A pump located in the sump is operated on a timer and provides water to the growing 20 tray via the top bowl, as discussed previously. Two drainage paths lead back to the sump. The first of these, which determines maximum water level when the pump is running, is the upper drainage point 42, of which two alternative constructions are shown in Figs. 5A and Fig. 5A shows one drainage point construction 42 consisting of a vertical tube 50 which screws into the growing tray to allow height adjustment. At the top of the tube are a pair of parallel disks 52,54 separated by a spacer 56. The gap between the disks is small enough to stop the ingress of material which could clog the drain, while still providing a large inlet area.

A second drainage point construction is shown in Fig. 5B, and consists of a perforated hollow sphere and a horizontal plate mounted on the externally threaded tube 50. Larger debris such as leaves tend to be trapped under the plate, and small debris is strained out by the perforations in the sphere.

o :'..Both the top bowl and the growing tray have emergency overflow slots 72, 74 in case of blockage of the respective drainage outlets.

20 The lower drainage path includes a drainage tube 43 in the channel 38, with a narrow opening which acts to strain out fine debris. In order to prevent clogging of this narrow opening, the drainage tube is connected via a bleed-off line 44 to the pump outlet, and thus a 25 small flow of water passes out of the opening when the pump is on. If desired, a tap (not shown) may be used to adjust the relative flow through the drainage tube and the top fluid outlet nozzle 22.

As can be seen from Fig. i, the base of the sump has a smaller area than its top, enabling the unit to be set up on a relatively small flat surface, for example a window ledge or very small table only 16 inches by 11 inches in area. This small base also has the advantage of requiring a reduced volume of liquid in the system. The sump is broader at its top to provide solid support of a wider growth tray, to maximise the -7available plant growing area.

The growing tray is supported on and serves as a cover for the sump, thus providing a simple, compact construction for the unit. The enclosed space between the sump and the tray allows continuous recirculation of the sump solution by evaporation and condensation, helping to improve the water quality.

A peripheral trough may be fitted onto the outside edge of the growing tray to increase the growing area.

The trough may hold a number of plants in pots, or may be filled directly with growing medium. The trough .oo.

may contain adjustable fluid inlets and outlet valves 15 for the trough, to allow independent control of the growing conditions in the trough.

The plant growing unit according to the invention has been found by the inventor to provide a high plant 20 yield in a very small unit. For example, it is believed that a unit covering an area of just 0.5m x 0.6m will give a yield equivalent to about 4m in length of conventional hydroponics tubing. The compact design also helps minimise evaporation losses and facilitate moving of the device if necessary to suit lighting conditions. Also, the unit can be combined with a domestic aquarium, drawing the aquarium water as the plant nutrient solution, to make a more attractive unit for home use. For such use, it may be desired to pivot the lower drainage tube down to reduce the water level in the depressed channel 38, or to provide filter material in the channel.

The aerating actions of the fluid flow and the water conditioning provided by the aquatic plants have been found to keep the liquid in the system in good condition, encouraging vigorous plant growth and

I

-8increasing the life of the hydroponics medium. The unit also appears to encourage condensation on the angled lower surfaces of the growing tray, falling back into the sump, and the top bowl, falling into the growing tray. It is believed that this helps inhibit growth of mould and mildew in the unit, as well as minimising water losses from the system. At times when the water level in the growing tray drops below the cover 40 of the channel, condensation can also be observed on the lower surface of the cover.

While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in 15 other specific forms without departing from the essential characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being 20 indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (8)

1. Plant growing apparatus including an open top sump for containing a plant nutrient solution, a growing tray for supporting a plurality of plants and having a floor with a depressed portion adapted to contain water conditioning means, said growing tray being supported on and substantially covering the sump, means for pumping the solution from the sump and contacting it with the plants in the growing tray and drain means returning to the sump.

2. Plant growing apparatus according to claim 1 including means for aerating the solution before contacting it with the plants. *ee Plant growing apparatus according to claim 2 wherein said aerating means comprises means for swirling the solution in contact with air.

4. Plant growing apparatus according to claim 3 wherein said aerating means includes an outlet from a top bowl.

5. Plant growing apparatus according to claim 1 wherein at least part of the 1 20 solution is passed over the surface ofa filter in contact with air. a

6. Plant growing apparatus according to any preceding claim wherein the depressed portion has a cover adapted to support plants.

7. Plant growing apparatus according to claim 6 wherein said cover allows passage of light into said depressed portion.

8. Plant growing apparatus according to claim 1 wherein at least a part of said depressed portion is adapted to be permanently flooded.

9. Plant growing apparatus according to claim 8 wherein said flooded part of the depressed portion is adapted to contain aquatic plants. Plant growing apparatus substantially as herein described with reference to the accompany drawings. DATED this 24th day of December .1999 GEORGE F. BROADFOOT By his Patent Attorneys HALFORD CO 0, 0:*