GB2199475A

GB2199475A - Plant cultivation container

Info

Publication number: GB2199475A
Application number: GB08727817A
Authority: GB
Inventors: Arnold Rainbow
Original assignee: Fisons Ltd
Current assignee: Fisons Ltd
Priority date: 1986-11-27
Filing date: 1987-11-27
Publication date: 1988-07-13
Anticipated expiration: 2007-11-27
Also published as: GB8727817D0; GB2199475B

Abstract

A plant cultivation container comprises a reservoir, eg a flexibly walled sack (1) and contains an absorbent platform (2), eg of polyurethane foam, for cultivating plants. The platform (2) is capable of supporting one or more plant root balls (4) above nutrient solution contained in the reservoir (1). <IMAGE>

Description

PLANT CULTIVATION CONTAINER This invention relates to a plant cultivation container and a method of cultivating plants.

Portable, self-contained containers for growing plants, comprising a flexible walled sack which is filled with a suitable plant growth medium and then sealed, are well known. In use, such containers, which are frequently referred to as growing bags, are laid on the ground or on some other suitable surface at the site of use and an upper wall cut to enable plants to be inserted into the growth medium for cultivation therein.

Although these containers offer many advantages over the growing of plants in the native soil they are not entirely satisfactory.

Such growing bags suffer from the disadvantage that they are bulky, heavy and consequently expensive to transport, for example when despatched from manufacture to retail outlets. In addition, irrigation of a growing bag, particularly in the summer months can present problems.

On hot days conventional growing bags may require two waterings. If the growing medium dries out it is very difficult to wet on subsequent watering. In addition such bags are dirty to plant up.

Alternative portable growing systems based on hydroponic techniques have been proposed in which plants are grown in soil free conditions with the roots dipping in a nutrient solution. A major problem of conventional hydroponic installations is that aeration of the nutrient solution is necessary to ensure the fresh supply of oxygen and the removal of carbon dioxide released by the roots.

Insufficient aeration leads to root death. These hydroponic techniques require a source of energy, to effect aeration, for example by continuous flow of aerated nutrient solution. Consequently such hydroponic systems suffer from the disadvantage that they tend to be cumbersome, expensive to run and are not readily portable. These systems are not suitable for the amateur grower.

We have now found a platform for growing plants which solves the problem of frequent watering required by conventional growing and does not require the aeration of nutrient solutions demanded by the conventional hydroponic systems.

According to the invention there is provided a plant cultivation container comprising a reservoir containing an absorbent plant platform for cultivating plants, the platform being capable of supporting one or more plant root balls above nutrient solution contained in the reservoir.

The absorbent platform is preferably an absorbent block through and over which roots from the root ball can extend such that roots are capable of absorbing nutrients contained in the reservoir and oxygen from the atmosphere.

The platform is preferably a synthetic organic material. We particularly prefer the platform to be an open-celled material, eg a hydrophilic foam. Suitable foams include polyphenyl foams and urea-formaldehyde foams. We especially prefer the platform to be a hydrophilic, open-celled polyurethane foam. The absorbancy of the platform is preferably such that the fluid, eg water, uptake is not too high, thus causing root loss and stem rot, or too low, thus exposing plants to dehydration stress.

We have found that a platform having a water holding capacity of 60 to 80% w/v is particularly effective.

We prefer the platform to have a low bulk density, eg a bulk density of less than 50g/litres, preferably less than 30g/litres, more preferably less than 20g/litres. We have found that a bulk density of from 12 to 17g/litres is particularly suitable.

The platform preferably wets, ie takes up water, in less than 5 minutes. We particularly prefer a platform which is able to wet to saturation in less than three minutes. Wetting times may be calculated by measuring the time taken for a block derived from the platform floated on the water surface to be fully immersed. We prefer polyurethane foams with an isocyanate index of 25-40%.

The platform preferably has a water:air holding ratio of from 1:1 to 5:1 v/v, eg 2:1.

The platform may take the form of a rectangular block. However we prefer the platform when used in association with a reservoir to form a growing assembly, to be triangular in section. We particularly prefer the section to be that of a right angled isoscles triangle.

The platform may be provided with a depression in its upper portion adapted to receive one or more plant root balls. The depression may be for example, in the form of a channel. We prefer the platform to include one or more cavities adapted to receive a plant root ball.

We prefer the platform to be made of a flexible material. This has the advantage that the platform is less likely to be damaged in transit and also allows, when cavities are present, a firm grip on plant root balls to be obtained.

The width, depth and spacing of the cavities will depend for example on the size of the platform, in particular its length, and the type of plant to be grown.

However in general we prefer the cavities to be from 10 to 50cm, eg 30cm apart. The cavities may be polygonal, eg square or hexagonal in cross section. We prefer the cavities to be circular in section. We particularly prefer t'ne cavities to taper, in order that a variety of sizes of root ball can be accommodated. The cavities may be from 5 to 15cm, eg 10cm wide and 5 to 15cm, eg 10cm deep. When the platform is triangular in section, the cavities are preferably in the widest angled vertex.

The reservoir is preferably a flexible walled container, especially similar to a bag, similar in size and shape to bags presently used for peat based growing bags. The reservoir preferably encloses at least the lower portion of the platform. Typically the bag may be 1.1 metres long, 0.45 metres wide and 0.35 metres deep.

The reservoir, in addition to a floor and side walls, is preferably provided with a top face provided with one or more apertures which allow the insertion of one or more plant root balls into the growing assembly.

The reservoir is preferably made of material which is opaque to visible light, resistant to degradation by ultraviolet light, resistant to puncturing and impervious to water, eg an opaque plastics material such as heavy duty polythene or polypropylene. The material may be, for example, a cross-laminated polyalkylene film, in which the film comprises from three to six, eg four layers of polyalkylene sheet. The polyalkylene is preferably UV stabilised. We particularly prefer the material to be four-ply cross-laminated polypropylene film. We prefer films in which the individual layers are stretched over grooved rollers. We prefer laminated film which has a 2 weight of 70 to 150g/m , more preferably 70 to 2 90g/m . A reservoir made from cross-ply polyalkylene film preferably includes an opaque inner layer.The outer layers of the film are preferably light coloured, eg yellow, to permit printing.

The nutrient solution capacity of the reservoir will depend upon the size of the platform, the number of plants that are to be grown in the container and the size and nature of the plants. In general the reservoirs can be manufactured in a wide range of sizes, eg having a solution capacity of from 0.5 to 50 litres, eg. 10 to 20 litres.

The plant cultivation container can be supplied, eg from a garden centre, with one or more platforms in place in the reservoir. In such circumstances the user is merely required to add water and, if necessary or desired, nutrients to the reservoir, before or after placing plants in the container. The plant cultivation container has the advantage over conventional peat based growing bags that the container is light, easy to transport, clean to plant up and in use requires less frequent watering. In addition the container is easier to wet than a conventional growing bag.

The plant cultivation container can also be supplied in the form of a kit in which the reservoir and one or more platforms are assembled by the consumer immediately prior to use.

According to the invention there is further provided a method of cultivating plants to a cropping stage, which comprises growing the plants on an absorbent block of open-celled polyurethane foam as hereinbefore described, wherein the blocks are located in a reservoir of nutrient solution.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings in which Figure 1 is a perspective view of a plant growth container according to the invention; Figure 2 is a side view, in section, of the plant growth container of figure 1; Figure 3 is a sectional view along the line X-X of figure 2; Figure 4 is a perspective view of an absorbent platform for use in association with a reservoir to form the plant growth container.

Referring first to figures 1, 2 and 3, a plant growth container according to the invention comprises a flexible walled sack 1 which encloses a triangular platform 2 of hydrophilic open celled polyurethane foam. The sack 1 acts as a reservoir for water and/or nutrient solution.

As is shown in figure 4, the upper portion of the platform 2 is provided with regularly spaced cavities 3 which are adapted to receive plant root balls. Each cavity is circular in horizontal section and tapers away from the upper portion in vertical section.

In use, the platform 2 is placed in the sack 1.

Plant root balls are inserted in the cavities 3 and the sack 1 filled to a depth of 1 to 10cm with nutrient solution. During growth, roots grow from the root balls and extend both through and over the platform 2. This allows the roots to absorb nutrients and water from the platform 2 and to absorb oxygen from the atmosphere. In particular the roots are exposed to an extended air/water interface, which helps encourage growth.

A particular feature of the invention is that watering is required at much less frequent intervals, eg 3 - 4 days, compared to twice daily waterings with conventional growing bags.

Claims

We claim:

1. A plant cultivation container comprising a reservoir containing an absorbent platform for cultivating plants, the platform being capable of supporting one or more plant root balls above nutrient solution contained in the reservoir.

2. A plant cultivation container according to Claim 1, wherein the platform is an absorbent block through and over which roots from the root balls can extend such that roots are capable of absorbing nutrients contained in the reservoir and oxygen from the atmosphere.

3. A plant cultivation container according to Claim 1 or Claim 2, wherein the platform is formed from an open celled foam material.

4. A plant cultivation container according to any one of the preceding claims, wherein the platform is formed from polyurethane foam.

5. A plant cultivation container according to any one of the preceding claims, wherein the platform is formed from a flexible foam.

6. A plant cultivation container according to any one of the preceding claims, wherein the platform has a water holding capacity of 60 to 80% w/v.

7. A plant cultivation container according to any one of the preceding claims, wherein the platform has a bulk density of less than 50g/litre.

8. A plant cultivation container according to any one of the preceding claims, wherein the reservoir is a flexible walled container.

9. A plant cultivation container according to any one of the preceding claims, wherein the reservoir is a flexible walled bag.

10. A plant cultivation container according to any one of the preceding claims, wherein the reservoir encloses at least the lower portion of the platform

11. A kit comprising a reservoir and an absorbent platform for cultivating plants for assembly to provide a plant cultivation container according to any one of the preceding claims.

12. A method of cultivating plants to a cropping stage, which comprises growing the plants on an absorbent block of open celled polyurethane foam, wherein the blocks are located in a reservoir of nutrient solution.

13. A plant cultivation container as hereinbefore described and with reference to the accompanying drawing.