GB1588174A - Plant growth vessels - Google Patents

Description

(54) IMPROVEMENTS IN PLANT GROWTH VESSELS (71) We, BORD NA MONA, a Statutory Corporation established under the laws of the Republic of Ireland, of Clanwilliam House, Mount Street Bridge, Dublin 2, Republic of Ireland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: The present invention relates to plant growth vessels and is particularly concerned with plant growth containers of the kind commonly referred to as "growing bags".

Growing bags are now widely used in horticulture especially for growing tomatoes and other plants under glass. Essentially they comprise an elongated bag or sack in the shape of a pillow, bolster or sausage-shaped, and may be of oval, rectangular, or circular cross-section. The bag is made from a flexible plastics material and contains a plant growth medium, more usually a peat based compost. In use the bags are laid in rows along the floor of the greenhouse. Plant growth apertures are cut in the uppermost walls of the bags, usually by removing panels from the wall of the bag or by cutting long slits in the wall. The plants are then planted in the plant growth medium through the apertures at desired spacings.In using growing bags for the growing of tomato plants, for example, the cultural method heretofore employed has been to supply water and dissolved nutrients to the plants by means of capillary tubes or trickle-feed pipe lines which are led into the growth medium through the plant growth apertures in the top of the bags. However, this method has not been entirely satisfactory due to difficulties in controlling the amount of liquid fed to each bag and to difficulties caused by blockages in the feed lines.

We have now found that a more satisfactory method of watering and feeding the plants is to lay the growing bags on a water porous bed which may be a porous sand bench but preferably is a capillary matting of material made from synthetic or natural fibres. Such capillary matting is known per se and has been used for watering and feeding plants grown in pots which are laid on the matting. The mats are kept sufficiently moist by a manually or automatically controlled feed system which may, for example, be a siphon system or an electrically controlled system, e.g. an "electronic leaf" system which measures the drying rate of the surface of the mat, or a system using a photoelectric cell which estimates the amount of solar energy reaching the plants and alters the water flow accordingly. Such water feed systems are well known per se.We have now found that if the growing bags are laid on such porous mats, the necessary water requirements of the plants can be absorbed by the plant growth medium in the bag from the mats through holes cut in a wall of the bag which is in contact with the mat.

According to the invention a method of cultivating plants comprises utilising a plant growth vessel comprising a container in the form of a sack or bag made from a flexible plastics material and containing a plant growth medium, wherein at least one wall of the container is permeable to water but substantially impermeable to the plant growth medium within the container, wherein the vessel is placed on a porous matting with the water permeable wall of the container in contact with the matting, planting plants in a plant growth aperture or apertures cut in a wall of the container opposite said water permeable wall, and supplying water and/or liquid nutrients to said porous matting. The invention also includes the plant growth vessel when used in said method. Preferably, the container is made from a flexible plastics material.The term "plant growth medium" is intended to refer to a particulate solid material, e.g. a peat-based compost, as distinct from a purely liquid medium and the words "substantially impermeable to the plant growth medium" is intended to indicate that the material cannot pass through the wall of the container in a substantial amount.

In one embodiment of the plant growth vessel, at least that portion of one long wall of the container opposite to the proposed location of the plant growth apertures is provided with a plurality of apertures which are of such a size and number that when the bag is laid on a porous mat with said wall in contact with the mat sufficient water for plant growth purposes can be absorbed from the mat through said holes by the growing medium within the bag but the holes are not sufficiently large to permit a substantial amount of the plant growth medium to leave the bag during normal handling of the bag. Where the growing medium is a peat compost for example, the apertures are preferably of a size which is less than the average particle size of the peat. Suitably, the apertures have an average diameter in the range 0.25 to 50 mm, preferably in the range 0.5 to 5.0 mm.Thus, for example, the bag may carry on one wall instructions or markings indicating the location at which a single or a plurality of plant growth apertures may be cut, while at least a substantial part of the surface of the wall of the bag opposite the wall which is to contain the plant growth apertures is porous, the pores being in the form of a multiplicity of minute holes pricked in the wall of the bag.

It has been found that apertures of the following sizes and numbers in the wall of the bag give satisfactory results: Approx. diameter Number Approx. diameter Number size of apertures of apertures size of apertures of apertures in wall of bag in wall of bag 1 mm 1,000 3 mm 100 1 mm 2,000 3 mm 200 2 mm 250 4 mm 50 2 mm 500 4 mm 100 In another embodiment at least one wall of the bag is made from a water permeable material, for example a water permeable plastics material, a porous material such as a natural or synthetic material from which the conventional porous matting referred to above is made, a net material of suitable mesh size or a woven material (for example woven polypropylene).

If desired, the water permeable wall or portion of the wall of the bag, can be rendered temporarily moisture impermeable by a removable cover or other means so as to prevent substantial release of moisture from the bag during storage.

Thus, using the bags of the invention all the user has to do is lay the growing bag on a porous mat with the water permeable wall of the bag in contact with the mat, and then cut plant growth apertures in the opposite wall of the bag.

One method of using the growing bags of the invention is illustrated with reference to the accompanying drawing.

Rows of growing bags 1 containing a peat-based compost are placed on strips 2 of porous matting material. The porous matting material may comprise a polyester based fibre matting and the strips are suitably 30 cm wide. The strips 2 of the matting are preferably located in trenches 4 about 2.5 to 5.0 cm deep, formed in the border soil. In this way seepage of water from the matting on to the path between the rows is avoided. The matting strips 2 are isolated from the border soil by means of sheets 5 of polythene laid below the strips 2. Crop irrigation is controlled by an electronic irrigation controller 6. The controller 6 preferably comprises a capacitor which senses changes in the moisture level of the matting. Up to four controllers 6 are used per acre. Each controller is preferably located at a location 3 to 4 m along the row, at the end nearest the central path. They may be spaced 20 to 30 m apart along the central path and on either side of it. The controllers 6 directly control irrigation through 23 volt solenoid valves 7 positioned on the irrigation lines 8.

Preferably, a logic unit (not illustrated) is provided to control, for example, up to six of the irrigation controllers 6. The purpose of the logic unit is to operate the solenoid valves in a predetermined sequence so as to avoid an excess demand on the water supply, which might occur should the irrigation controllers 6 act more or less simultaneously to open the solenoid valves. If desired, a suitable over-riding control or fail-safe system may be included so as to avoid over-watering in the event of malfunctioning of the controllers 6.

In use, the growing bags 1 are laid in rows end to end on the strips of matting 2, with the water-permeable wall of the bag in contact with the matting 2. Alternatively, the matting may first be covered with a layer of black polythene or other plastics material which is provided with a multiplicity of holes similar to those in the wall of the growing bag. The bags are then laid on this layer. This method has the advantage that the growth of unsightly algae on the areas of matting which would otherwise be exposed to the light is avoided.

Plant growth apertures are cut in the top wall of the bags and the plants are planted through the apertures. However, before planting, the peat in the bags may, if desired, be moistened by applying, in the case of tomatoes, about 4.5 litres of water per plant. After planting, all subsequent watering is effected by means of the capillary irrigation system described above.

Suitably, the irrigation controllers 6 are pre-set to maintain the matting at a zero water tension and consequently maintaining the peat in the bags at a low water tension of approximately 10 cm. The capillary matting 2 can be effectively and cheaply sterilised at the end of the growing season by using a hypochloride bleach.

The irrigation system of the invention offers a number of advantages over known systems. It is found that the water is maintained at a constant tension in the peat and is only replenished to meet evapotranspiration requirements. Root growth and distribution in the growing medium is not adversely affected by a highly varying situation of low moisture stress to excess water supply often experienced in surface watered composts. By maintaining a high and constant moisture tension salt concentration is kept constant and relatively low.

WHAT WE CLAIM IS: 1. A method of cultivating plants which comprises utilising a plant growth vessel comprising a container in the form of a sack or bag made from a flexible plastics material and containing a plant growth medium, wherein at least one wall of the container is permeable to water but substantially impermeable to the plant growth medium within the container, wherein the vessel is placed on a porous matting with the water permeable wall of the container in contact with the matting, planting plants in a plant growth aperture or apertures cut in a wall of the container opposite said water permeable wall, and supplying water and/or liquid nutrients to said porous matting.

2. A plant growth vessel when used in the method of Claim 1 comprising a container in the form of a sack or bag made from a flexible plastics material and containing a plant growth medium, wherein at least one wall of the container is permeable to water but substantially impermeable to the plant growth medium within the container.

3. A plant growth vessel as claimed in Claim 2, wherein at least one long wall of the container is provided with a multiplicity of apertures which are of such a size and number that when the container is laid on a porous mat with said wall in contact with the mat sufficient water for plant growth purposes can be absorbed from the mat through said holes.

4. A plant growth vessel as claimed in Claim 3, wherein the apertures each have an average diameter in the range 0.5 to 5.0 mm.

5. A plant growth vessel as claimed in Claim 2, wherein at least a substantial part of the surface of one wall of the container is porous.

6. A plant growth vessel as claimed in Claim 5, wherein the pores are in the form of a multiplicity of minute holes in the wall of the container.

7. A plant growth vessel as claimed in any of Claims 3 to 6, wherein the apertures or holes may number from 50 to 2,000.

8. A plant growth vessel as claimed in any of Claims 3 to 6, wherein the wall of the bag opposite to that in which said apertures or holes are provided carries thereon instructions or markings indicating the location at which a single, or a plurality of plant growth apertures may be cut.

9. A plant growth vessel as claimed in any of Claims 2 to 8 made from a flexible plastics material.

10. A plant growth vessel as claimed in Claim 2, wherein at least one wall of the container is made from water permeable material.

11. A plant growth vessel as claimed in Claim 10, wherein at least one wall of the container is made from a water permeable plastics material, a woven material, a net material of suitable mesh size, or -a porous material.

12. A plant growth vessel as claimed in any of Claims 2 to 11, wherein the water permeable wall of the container is provided with a removable water impermeable cover.

13. A plant growth vessel substantially as hereinbefore described with reference to the drawing.

14. A method for cultivating plants substantially as hereinbefore described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (15)

**WARNING** start of CLMS field may overlap end of DESC **. water-permeable wall of the bag in contact with the matting 2. Alternatively, the matting may first be covered with a layer of black polythene or other plastics material which is provided with a multiplicity of holes similar to those in the wall of the growing bag. The bags are then laid on this layer. This method has the advantage that the growth of unsightly algae on the areas of matting which would otherwise be exposed to the light is avoided. Plant growth apertures are cut in the top wall of the bags and the plants are planted through the apertures. However, before planting, the peat in the bags may, if desired, be moistened by applying, in the case of tomatoes, about 4.5 litres of water per plant. After planting, all subsequent watering is effected by means of the capillary irrigation system described above. Suitably, the irrigation controllers 6 are pre-set to maintain the matting at a zero water tension and consequently maintaining the peat in the bags at a low water tension of approximately 10 cm. The capillary matting 2 can be effectively and cheaply sterilised at the end of the growing season by using a hypochloride bleach. The irrigation system of the invention offers a number of advantages over known systems. It is found that the water is maintained at a constant tension in the peat and is only replenished to meet evapotranspiration requirements. Root growth and distribution in the growing medium is not adversely affected by a highly varying situation of low moisture stress to excess water supply often experienced in surface watered composts. By maintaining a high and constant moisture tension salt concentration is kept constant and relatively low. WHAT WE CLAIM IS:

1. A method of cultivating plants which comprises utilising a plant growth vessel comprising a container in the form of a sack or bag made from a flexible plastics material and containing a plant growth medium, wherein at least one wall of the container is permeable to water but substantially impermeable to the plant growth medium within the container, wherein the vessel is placed on a porous matting with the water permeable wall of the container in contact with the matting, planting plants in a plant growth aperture or apertures cut in a wall of the container opposite said water permeable wall, and supplying water and/or liquid nutrients to said porous matting.

2. A plant growth vessel when used in the method of Claim 1 comprising a container in the form of a sack or bag made from a flexible plastics material and containing a plant growth medium, wherein at least one wall of the container is permeable to water but substantially impermeable to the plant growth medium within the container.

3. A plant growth vessel as claimed in Claim 2, wherein at least one long wall of the container is provided with a multiplicity of apertures which are of such a size and number that when the container is laid on a porous mat with said wall in contact with the mat sufficient water for plant growth purposes can be absorbed from the mat through said holes.

4. A plant growth vessel as claimed in Claim 3, wherein the apertures each have an average diameter in the range 0.5 to 5.0 mm.

5. A plant growth vessel as claimed in Claim 2, wherein at least a substantial part of the surface of one wall of the container is porous.

6. A plant growth vessel as claimed in Claim 5, wherein the pores are in the form of a multiplicity of minute holes in the wall of the container.

7. A plant growth vessel as claimed in any of Claims 3 to 6, wherein the apertures or holes may number from 50 to 2,000.

8. A plant growth vessel as claimed in any of Claims 3 to 6, wherein the wall of the bag opposite to that in which said apertures or holes are provided carries thereon instructions or markings indicating the location at which a single, or a plurality of plant growth apertures may be cut.

9. A plant growth vessel as claimed in any of Claims 2 to 8 made from a flexible plastics material.

10. A plant growth vessel as claimed in Claim 2, wherein at least one wall of the container is made from water permeable material.

11. A plant growth vessel as claimed in Claim 10, wherein at least one wall of the container is made from a water permeable plastics material, a woven material, a net material of suitable mesh size, or -a porous material.

12. A plant growth vessel as claimed in any of Claims 2 to 11, wherein the water permeable wall of the container is provided with a removable water impermeable cover.

13. A plant growth vessel substantially as hereinbefore described with reference to the drawing.

14. A method for cultivating plants substantially as hereinbefore described with reference to the accompanying drawing.

15. A plant growth vessel as claimed in any of Claims 2 to 13 in combination with porous matting.