Movable root contact-pressure plate assembly for hydroponic system

• US 4,860,490 A
• Filed: 02/16/1988
• Issued: 08/29/1989
• Est. Priority Date: 02/16/1988
• Status: Expired due to Term

• Current Assignee: Tuskegee University
• Original Assignee: Tuskegee University
• Inventors: Morris, Carlton E., Bonsi, Conrad K., Loretan, Philip A., Hill, Walter A.
• Primary Examiner(s): DeMille, Danton D.
• Application Number:
  US07/156,013
• Time in Patent Office: 560 Days
• Field of Search: 47/59, 47/62, 47/63, 47/64, 47/65, 47/79, 47/80, 47/41.11, 47/14
• US Class Current: 47/63
• CPC Class Codes: A01G 31/02 Special apparatus therefor self-acting watering devices A01G27/00
• CPC Class Codes: Y02P 60/21 Dinitrogen oxide [N2O], e.g. using aquaponics, hydroponics or efficiency measures

Abstract

A hydroponic system for growing sweet potatoes and other root and tuber crops includes a growing channel incorporating a movable root contact/pressure plate assembly. The assembly consists of a flat, rigid PVC plate in which holes for inserting plants are drilled and a flexible vinyl film which is secured along the length of each side edge of the plate, by means of pressure fit connectors. The assembly is secured to the top edges of a growing channel, again by pressure fit connectors. The flexible film suspends the plate near and parallel to the bottom of the growing channel, with the flexibility of the film allowing upward movement of the plate within the channel as the plant roots grow. The assembly provides contact and pressure to the plant roots inside the growing channel thereby promoting enlargement of the roots. This enlargement causes the assembly to move upwardly, thereby maintaining the desired pressure conditions during growth. A suitable nutrient solution is suppplied in the growing channel.

Claims

1. A hydroponic system for growing root crops in the absence of an aggregate, and for stimulating the growth of storage roots by the application of continuous downward pressure to such roots, comprising:

a growing channel having a bottom wall and side and end walls, and having an open top;

movable root contact/pressure plate means within said growing channel and spaced above the bottom wall thereof to define a root zone, said contact/pressure plate means having a weight selected to provide a growth-stimulating pressure on storage roots within said root zone;

plant support means in said plate means for receiving and supporting crop plants having storage roots with their storage roots extending below said plate into said root zone;

flexible sheet means interconnecting said plate means with the side walls of the growing channel for substantially free vertical motion of said plate means within said channel, said plate means being positioned by said flexible sheet means to contact and continuously apply the weight of said contact/pressure plate means and thereby said growth-stimulating pressure on storage roots within said root zone to thereby promote storage root growth, said flexible sheet means permitting vertical motion of said plate means in response to storage root growth to accommodate root enlargement while retaining plate pressure on said storage roots; and

means supplying liquid nutrient to said root zone in said growing channel to contact the roots of plants carried in said plant support means.

2. The system of claim 1, wherein said flexible sheet means is substantially coextensive with said plate means and extends between said plate means and said side walls of said channel.

3. The system of claim 1, wherein said liquid-supplying means includes a reservoir for receiving a supply of nutrient, feed pipe means leading from said reservoir to said growing channel, and drain pipe means leading from said growing channel to said reservoir.

4. The system of claim 3, wherein said flexible sheet means in opaque to light.

5. The system of claim 3, further including means for controlling the flow of nutrient from said reservoir to said growing channel.

6. The system of claim 1, wherein said growing channel is elongated, and wherein said contact/pressure plate means is elongated and extends substantially the entire length of said growing channel.

7. The system of claim 6, wherein said plate means and said flexible sheet means form an elongated contact/pressure assembly extending substantially the entire length of, and across the width of, said growing channel.

8. The system of claim 7, wherein said plant support means includes a plurality of plant-receiving apertures spaced along the length of said plate means.

9. The system of claim 7, wherein said flexible sheet means includes a first flexible film extending between a first longitudinal side edge of said elongated plate means and the top edge of a corresponding first side wall of said growing channel and a second flexible film extending between a second longitudinal side edge of said elongated plates means and the top edge of a corresponding second side wall of said growing channel.

10. The system of claim 9, further including first and second plate connector means for securing said first and second films to corresponding first and second side edges of said elongated plate means.

11. The system of claim 10, wherein each of said plate connector means comprises an elongated connector having a channel for receiving an edge portion of said film and the side edge of said elongated plate means to secure said film edge portion in said plate connector channel.

12. The system of claim 9, further including first and second edge connector means for securing said first and second films to the top edges of corresponding first and second side walls of said channel.

13. The system of claim 12, wherein each of said edge connectors comprises:

an elongated connector having a first, downwardly-facing channel for frictionally engaging a top edge of a side wall and having a second, upwardly-facing channel for receiving an upper edge portion of said film; and

a removable filler bar for said upwardly-facing channel, said filler bar engaging the upper edge portion of said film within said upwardly facing channel to secure the film therein.

14. The system of claim 13, further including first and second plate connector means for securing the lower edge portions of said first and second films to corresponding first and second side edges of said elongated plate means.

15. The system of claim 14, wherein each of said plate connector means comprises an elongated connector having a channel for receiving an edge portion of said film and the side edge of said elongated plate memo to secure said film lower edge portion in said plate connector channel.

16. The system of claim 1, wherein said plate means forms a rigid top wall for said root zone and wherein said channel walls cooperate with said plate means to further define said root zone to provide rigid contact surfaces for storage roots to stimulate storage root enlargement.

17. A hydroponic system for growing root crops by the application of continuous predetermined downward pressure to storage roots for stimulating the growth of such roots, comprising:

a growing channel having a wall portion, a closed bottom, and having an open top;

a movable storage root contact assembly within said growing channel, said assembly including;

(a) plant support plate means, said support plate means having a weight sufficient to promote storage root growth; and

(b) flexible sheet means extending between said wall portion and said plate means to support said plate means within said growing channel a small distance above the bottom thereof to define a root chamber between said growing channel bottom and said plate means, said sheet means being sufficiently flexible to permit free upward motion of said plate means within said growing channel in response to growth of storage roots in said root chamber;

means supplying nutrient to said root chamber;

means removing excess nutrient from said root chamber;

at least one plant-receiving aperture in said plate means for receiving a plant having storage roots to be grown and for locating the storage roots of the plant in said root chamber;

adjustable means for positioning said root contact assembly to position said plate means to initially contact and to produce said growth stimulating pressure continuously downwardly on storage roots in said root chamber to stimulate growth of said storage roots and to accommodate enlargement of the storage roots while sustaining the predetermined downward pressure thereon; and

said assembly being opaque to prevent light from reaching said root chamber and any storage roots growing therein.

18. The system of claim 17, wherein said flexible sheet means is coextensive with said plate means and said wall portion to prevent light from reaching said nutrient in said root chamber.

19. A method for growing root plants hydroponically and for stimulating the growth of storage roots through the continuous application of predetermined downward pressure to the storage roots, comprising:

supplying a nutrient solution to a plant growing channel;

suspending in said channel a root contact/pressure plate assembly, said assembly including a plate having a predetermined weight selected to provide a growth-stimulating pressure on storage roots, wherein said plate is suspended above the bottom wall of said growing channel to form a root zone containing said nutrient solution;

supporting in apertures forming in said plate assembly root crop plants having storage roots with the storage roots of the plants extending below the plate assembly into said root zone and into contact with said nutrient solution;

adjusting the position of said plate assembly to cause said plate assembly initially to contact and to apply the weight of said plate to exert said predetermined growth-stimulating pressure downwardly on said storage roots to thereby promote storage root growth; and

wherein said plate assembly is suspended to allow substantially free vertical motion for said plate assembly in response to the growth of said storage roots to move said plate assembly upwardly to accommodate said growth while continuously providing said predetermined pressure thereon.