GB2139609A

GB2139609A - Plant growing media

Info

Publication number: GB2139609A
Application number: GB08412012A
Authority: GB
Inventors: Allan Cooke
Original assignee: Chemical Discoveries SA
Current assignee: Chemical Discoveries SA
Priority date: 1983-05-10
Filing date: 1984-05-10
Publication date: 1984-11-14
Also published as: GB8412012D0; GB2139609B

Abstract

A growing medium for plants is prepared by mixing a particulate growing material derived from palm nuts, such as coir fibres, with a highly water absorbent polymer.

Description

SPECIFICATION Plant growing media This invention relates to growing media for plants.

British Patent Specification No. 2127005 discloses a method of producing a growing medium wherein a mass of particulate growing material is mixed with a minor proportion of a synthetic polymeric substance which has the property of absorbing a volume of water appreciably greater than its own volume in a state in which said absorbed water is freely available for transfer from the polymeric substance to the root system of a plant growing in the medium.

As described in the specification of the Patent Application, the growing material with which the polymeric material is mixed may consist of or include an inorganic and/or organic substance, and specific reference is made to rockwool in this respect.

It has now been found that fibrous material derived from palm nuts, such as coconuts, particularly coir and/or coir pith, can be particularly advantageous for use as said growing material alone or mixed with any other suitable material, for example soil, rockwool or the like, as described in the aforementioned Patent Specification.

In a particularly preferred embodiment the material known as coir dust is mixed with the polymeric material with the latter material constituting up to 50% by weight of the mixture. If desired low levels of polymeric material can be used, say as low as 1% or less by weight of the mixture.

Coir fibres are obtained from the husk or inner surface of the shell of the palm nut.

These fibres are process.ed to give a material suitable for use in the manufacture of matting and other products. Coir dust is the material, mostly composed of very short fibres, which is rejected, and normally discarded, during the processing stage.

Alternatively it is possible to use a granular powder comprising crushed fibres, somewhat similar to coir dust, obtained by crushing the entire husk i.e. shell and fibres of palm nuts.

Reference is hereby made to U.K. Specification 21 27005 for details of the polymeric substance, other materials which can be used as part of the growing material and other pertinent aspects.

In particular, the polymeric substance is preferably formed by polymerising an acrylamide monomer in the presence of N,N'-methylene bisacrylamide as cross-linking agent (preferably up to 5% by weight relative to the acrylamide), the reaction conditions being selected to give in effect a three-dimensional polymeric matrix having multiple free chain ends, such substance being such as to absorb water (say at least 30 times its own volume) to give a firm gel-like material which is sticky or tacky so as to be capable of adhering to plant roots whilst permitting migration of water droplets trapped within the matrix to the plant roots.

A polymeric binder such as acrylamide/acrylic acid polymer may also be incorporated.

1. A method of producing a growing medium wherein a mass of particulate growing material is mixed with a minor proportion of a synthetic polymeric substance, characterised in that said polymeric substance has the property of absorbing a volume of water appreciably greater than its own volume in a state in which said absorbed water is freely available for transfer from the polymeric substance to the root system of a plant growing in the medium, and said particulate growing material comprises fibrous material derived from palm nuts.

2. A method according to claim 1, wherein said fibrous material comprises coir and/or coir pith.

3. A method according to claim 2, wherein said fibrous material comprises coir dust.

4. A method according to any one of claims 1 to 3, characterised in that said polymeric substance comprises an acrylamide polymer cross-linked with N,N'-methylene bisacrylamide which absorbs water to form a sticky gel.

5. A method according to any one of claims 1 to 4, characterised in that said polymeric substance is capable of absorbing at least 30 times its own volume of water.

6. A method according to any one of claims 1 to 5, characterised in that said polymeric substance amounts to 1% or less of the volume of the said growing medium.

7. A method according to any one of claims 1 to 6, characterised in that the said fibrous material constitutes the sole said growing material.

8. A method according to any one of claims 1 to 7, characterised in that said growing medium further incorporates a polymeric binder.

9. A method according to claim 8, characterised in that said binder is an acrylamide/acrylic acid polymer.

1 0. A growing medium when prepared by the method of any one of claims 1 to 9.

11. A growing medium comprising a mixture of fibrous material derived from palm nuts with a particulate synthetic polymeric substance, wherein said polymeric substance represents up to 1% by weight of the mediumm, and said polymeric substance comprises an acrylamide polymer cross-linked with up to 5% by weight (relative to the acrylamide) of N,N'-methylene bisacrylamide which absorbs at least 30 times its own volume of

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Plant growing media This invention relates to growing media for plants. British Patent Specification No. 2127005 discloses a method of producing a growing medium wherein a mass of particulate growing material is mixed with a minor proportion of a synthetic polymeric substance which has the property of absorbing a volume of water appreciably greater than its own volume in a state in which said absorbed water is freely available for transfer from the polymeric substance to the root system of a plant growing in the medium. As described in the specification of the Patent Application, the growing material with which the polymeric material is mixed may consist of or include an inorganic and/or organic substance, and specific reference is made to rockwool in this respect. It has now been found that fibrous material derived from palm nuts, such as coconuts, particularly coir and/or coir pith, can be particularly advantageous for use as said growing material alone or mixed with any other suitable material, for example soil, rockwool or the like, as described in the aforementioned Patent Specification. In a particularly preferred embodiment the material known as coir dust is mixed with the polymeric material with the latter material constituting up to 50% by weight of the mixture. If desired low levels of polymeric material can be used, say as low as 1% or less by weight of the mixture. Coir fibres are obtained from the husk or inner surface of the shell of the palm nut. These fibres are process.ed to give a material suitable for use in the manufacture of matting and other products. Coir dust is the material, mostly composed of very short fibres, which is rejected, and normally discarded, during the processing stage. Alternatively it is possible to use a granular powder comprising crushed fibres, somewhat similar to coir dust, obtained by crushing the entire husk i.e. shell and fibres of palm nuts. Reference is hereby made to U.K. Specification 21 27005 for details of the polymeric substance, other materials which can be used as part of the growing material and other pertinent aspects. In particular, the polymeric substance is preferably formed by polymerising an acrylamide monomer in the presence of N,N'-methylene bisacrylamide as cross-linking agent (preferably up to 5% by weight relative to the acrylamide), the reaction conditions being selected to give in effect a three-dimensional polymeric matrix having multiple free chain ends, such substance being such as to absorb water (say at least 30 times its own volume) to give a firm gel-like material which is sticky or tacky so as to be capable of adhering to plant roots whilst permitting migration of water droplets trapped within the matrix to the plant roots. A polymeric binder such as acrylamide/acrylic acid polymer may also be incorporated. CLAIMS

1 0. A growing medium when prepared by the method of any one of claims 1 to 9.

11. A growing medium comprising a mixture of fibrous material derived from palm nuts with a particulate synthetic polymeric substance, wherein said polymeric substance represents up to 1% by weight of the mediumm, and said polymeric substance comprises an acrylamide polymer cross-linked with up to 5% by weight (relative to the acrylamide) of N,N'-methylene bisacrylamide which absorbs at least 30 times its own volume of water to form a sticky gel.