WO2004095924A1

WO2004095924A1 - Horticultural gel

Info

Publication number: WO2004095924A1
Application number: PCT/GB2004/001769
Authority: WO
Inventors: Richard Michael Fenwick
Original assignee: Richard Michael Fenwick
Priority date: 2003-04-26
Filing date: 2004-04-26
Publication date: 2004-11-11
Also published as: GB0309585D0; EP1619946A1

Abstract

A horticultural gel comprising a solid or semi solid gel for use in horticultural applications, wherein the gel comprises gelling material in an amount of 8 g or greater than 8g per litre; a gelling material for a horticultural gel comprising a mixture of two or more inert gelling components for suitable binding together to form a barrier to prevent germination of weeds; a method of preparation thereof comprising combining a gelling material with fluid, blending and/or warming and/or boiling to dissolve and transferring to a mould, container or surface and allowing to set; a method of application thereof to a weed prone surface comprising obtaining gel and applying to a weed prone surface in a depth of approximately 8 to 100 mm; and a continuous covering means comprising a shaped card or paper insert having an aperture in the centre through which a growing plant may emerge or protrude optionally comprising a slit from aperture to outside edge on one or both sides.

Description

HORTICULTURAL GEL

The present invention relates to a horticultural gel for applying to a weed prone surface, a method for the preparation thereof, and a method and device for the application thereof.

Growth of weed or undesired vegetation is suppressed in private and commercial horticultural applications by various chemical and physical means. Herbicides are applied as spray or solution to soil, on small and large scale. Physical barriers such as continuous subsurface sheeting having holes for penetration of desired plants are also used on both small and large scale. Surface barriers comprising bark chippings, gravel, glass beads and the like are also used as a surface covering scattered around the base of desired plants. Continuous surface barriers such as fabric matting which may or may not be impregnated with herbicides or growth promoters which may be cut to slot around a growing plant are also in common use.

Physical barriers are however ineffective on the whole, bark granules need to be provided to a thickness of several inches deep to work and take up too much pot depth on a small application. On a larger application they are expensive and at best reduce weed growth rather than suppress, having also a decorative effect. Gravel suffers from the same disadvantages. Surface coverings such as a mat work where the mat is in place but not around the aperture which is the most sensitive location for weed growth in terms of effecting the growth of the desired plant. They are only suitable for a single stem plant since multiple stem plants would push them away from the surface. Sub-soil coverings suffer from the same disadvantages, so although they are generally effective where the covering is in place, they permit weed growth at apertures for plants, and are expensive and labour intensive.

Accordingly there is a need for an alternative effective weed suppressant which may be used as a physical barrier for small or large scale weed suppression.

We have now surprisingly found that a weed suppressant may be provided comprised of particular material and a particular form which combines the advantages of particulate and continuous physical barriers and gives effective and long lasting suppression of weed growth.

In its broadest aspect there is provided according to the present invention a horticultural gel comprising a solid or semi solid gel for use in horticultural applications, wherein the gel comprises gelling material in an amount of 8g or greater than 8g per litre fluid (0.8% or greater than 0.8% gelling material based on fluid and gelling material).

The horticultural gel of the invention may be suited for a number of horticultural applications. In a first embodiment, the gel is a weed suppressant gel and is adapted to be applied as a weed-suppressing layer to a weed prone and to release fluid with time to form a residue in the form of a weed- suppressing residual layer.

The residual layer may be discrete or continuous. Preferably a continuous residual layer comprises apertures which form naturally on fluid loss and residue formation. Preferably surface coverage prior to and after full fluid release is in the range 100-50%, more preferably 100-80%. This has the advantage that the residue still provides good weed suppressant effect after full fluid loss.

A weed prone surface is suitably any plant locus, typically a soil surface, and may be an interior or exterior soil bed, field or the like, a potted soil surface and the like.

The horticultural gel of the present invention therefore provides a continuous particulate or semi-particulate soil covering which can be located snugly around the base of any plant or plant stems to prevent weed growth thereabout, and optionally allows penetration of stronger desired plant growth, and moreover on degradation provides the advantages of continuous covering, in improved manner whereby the continuous residue extends snugly to surround the base of the desired plant stems.

Preferably gel is effective for weed suppression, when applied in a depth, depending on the concentration of the gelling material used in the gel, of approximately 8- 100mm, for example 8-60mm, preferably in excess of approximately 8-12 mm, to give a residue of minimum thickness 1-3 mm, e.g. 1-2 mm after residue formation.

The gel may be comprised in gel body form, for example a gel block for cutting into smaller shapes, discrete gel shapes such as cubes, spheres, discs, polygonal blocks, decorative shapes and the like, or may be comprised in a container for dispensing or extrusion as a semi solid mixture of gel lumps. Preferably the gel is provided as a collection of discrete gel shapes or a semi- solid mass, suited for coverage of a surface area around or about a plant or its locus. Discrete gel shapes are preferably of size in at least one dimension in excess of 5mm, and are preferably of 5 to 60 mm, more preferably 5 to 40 mm in any dimension. It is a particular feature of the invention that gel shapes initially have sufficient weight and size to prevent dispersion by wind and the like. As they degrade, the gel shapes condense or settle together slightly so that they remain resistant to dispersion. This is very important in maintaining an effective barrier.

The horticultural gel of the invention may comprise an inert gelling component or a mixture of two or more inert gelling components which bind together to form a film residue as a barrier to prevent germination of weeds. Reference herein to inert is to chemically benign, not producing any bi- products.

The gel of the invention may be comprised of any gelling material, preferably a hydrocolloid of animal, bird, mammal, plant, micro-organism or synthetic origin, and mixtures thereof. Reference herein to a hydrocolloid is to any substance that forms a gel with water. Preferably gelling material is a substantially chemically inert material of any pH. Preferably gelling material is of pH 1-10.

More preferably the gel of the invention is comprised of a hydrocolloid comprising an animal, bird, mammal, micro-organism or plant protein or extract or synthetic equivalent, other synthetic hydrocolloids and the like, and mixtures thereof, more preferably is selected from gelatine, egg protein, milk protein, soy protein, gels based on edible gums or a blend of gums which include for example guar gum, xanthan gum, carrogeenan gum, carob gum, tara gum, konjac, cassia gum, polysaccharides such as extracts from algae, e.g. agar which is extracted from seaweeds, in particular red algae, alginate, furcelleran, pectin, cereal flours and starches, cellulose derivatives, chitin derivatives, bacterial fermentation gums such as gellan gum, polyvinylpyrrolidine, carbopol (a cross linked polyacrylic acid polymer) (BF Goodrich) and the like, and mixtures thereof. More preferably the gel of the invention is comprised of a hydrocolloid selected from animal protein or extract or micro-organism or plant protein or extract.

Readily available gel materials include plant and animal extracts, preferably plant extracts such as agar, gums and the like, or animal extracts such as gelatin and the like, and mixtures thereof. Agar is a polysaccharide of formula (C₁₂Hι₈0₉)_n and is commercially available (agar, agar flake, agar gum, Bengal, Bengal gelatin, Bengal isinglass, digenea, simplex mucilage, gelose, japan agar, japan isinglass, lay or carang). Gelatin is derived from animal tissues such as porcine skin and is commercially available (gelatin, gelatine, gelfoam, GT, pharmagel, puragel, spongiofort, vee vee gelatin).

Gels may be of stronger or weaker gelling hydrocolloids, for example agar gel is a high strength gel which may be used for applying around protruding plants or vigorous growing plants having the strength to penetrate the gel, whereas a gelatin or gum is a softer gel which may be suitable for applying over a weed prone surface for emerging plant growth.

Nature and amount of gelling material may also be selected for a desired water content and longevity. Agar retains its gel form for a period of the order of four to six months prior to residue formation, with increasing period of gel form retention with increasing agar content up to about 40g per litre fluid and the residue remains intact for a further period of four to six months whereas gelatin retains its gel form for a period of approximately two to four months and gelatin residue remains intact for a further period of two to four months. The gel of the invention comprises 8g or more gelling material per litre of fluid as hereinbefore defined. The gel strength is very specific for the needs of the invention, whereby a gel comprising less than 8g gelling material per litre fluid is too weak to suppress weed growth. Preferably therefore a gel of the invention comprises gelling material in an amount from 8 to 200g per litre fluid, preferably 10 to 60g per litre fluid, more preferably 10-50g per litre of fluid, more preferably 30-50g or 20-40g per litre fluid, for example 25-50g or 12-25g per litre fluid. Corresponding values given as a percentage are 0.8 to 15%, 1 to 6%, 1 to 5%, 3 to 5%, 2 to 4%, for example, 2.5-5% or 1.2-2.5% by weight of fluid and gelling material.

Gels are known, comprised of agar and the like, for biological and horticultural application specifically micropropagation, plant cloning, plantlet culture, embryo culture, cell culture, callus culture or tissue culture as a soil substitute, in which seeds or seedlings are seeded in a gel body or block. Such gels typically comprise agar in less than 6-8g per litre (less than 0.6-0.8%), to allow root and shoot development and growth. The gel of the invention is distinct from such micropropagation gels both in nature and purpose, and is distinguished by content of gelling material.

The gel may be of a mixture of gelling material, for example a mixture of agar and gelatin, or of agar and a gum or blend of gums, such as xantham carob, guar or carrogeenan gums, providing some of the longevity of the agar but with the pliability of the gelatin or gum. Preferably a mixture comprises from 33:67 to 50:50 by weight of agar: gelatin or gum. The gel may comprise any fluid which is able to evaporate over time and preferably comprises water, which may be deionised, purified such as distilled or regular tap water.

We have now found that the longevity and stability of the gel is affected by the prevailing temperature of a locus to which it is applied. In warmer climates it is therefore preferable to adapt the gel for enhanced moisture retention. The gel may therefore include additional substances such as humectants and substances which form a skin on the surface of the gel, or such additional substances may be applied to the final gel surface in order to slow down the rate of water loss through evaporation. Preferably a skin forming additional substance comprises liquid fertiliser or other salt containing agent, sucrose, dextrose, glucose and other syrups, carbohydrates including sugar alcohols such as glycerol, mannitol, sorbitol, maltitol, lactitol, invertase, invert sugar, zylitol, non fermentable carbohydrates such as polydextrose, or propylene glycol.

Humectant has been found to improve stability and longevity. Suitable humectants are Polyethylene glycol (PEG), Sorbitol, Maltitol, Polydextrose, Glyceryl triacetate, Xylitol, Propane diol, Propylene glycol and Glycerin among others. Preferred humectant includes PEG, PEG distearate, PEG mono or polyethylether of average molecular weight from 200 to 35,000 optionally as a solution with DMSO. Preferred molecular weight is in the range 200 to 1000, for a medium strength gel, or 1000 or more for a softer gel.

Preferably the gel additionally comprises a humectant, if present, in an amount 50 to 500g per litre fluid, more preferably in an amount 80 to 200g per litre fluid. The gel may also include a setting agent, such as a calcium source, in particular if fluid comprises "hard" water. Alternatively the gel may be derived by heat-induced setting.

Preferably the gel of the invention is substantially free of any solids. More preferably the gel is free of ungelled gelling material, plant matter such as seeds and the like, although added solids may be present as defined below. Preferably the gelling material is 80% up to substantially 100% hydrated.

The gel may or may not include additional substances for growth promotion effect, such as herbicides, pesticides, fungicides, growth promoters and the like. The gel may or may not include fumigants, which are generally undesired.

Preferably the gel is nutrient free in terms of encouraging plant growth. Preferably the gel is sterile. In a particular advantage this neutral, sterile, inert gel prevents weed germination into any weed prone surface such as compost, soil and the like, thus giving a weed free surface that is pleasing to the eye and allows a plant to develop without competition.

The gel may comprise colourant for decorative effect in situ. Preferably colouring comprises charcoal or food colouring and is preferably sugar free and inert.

The gel may additionally comprise an anti-bacterial or anti-microbial agent. Such agent has been found useful to suppress or inhibit the growth of bacteria on the gel surface and preserve the gel. Suitable agents may be selected from bleaches, preferably hydrogen peroxide, sodium hypochlorite and cationic or non-ionic surfactants or anionic detergents or known food preservatives, such as sorbic acid, sodium sorbate, potassium sorbate, calcium sorbate, benzoic acid, sodium benzoate, potassium benzoate, calcium benzoate, ethyl para- hydroxybenzoate, sodium ethyl para-hydroxybenzoate, propyl para- hydroxybenzoate, sodium propyl para-hydroxybenzoate, methyl para- hydroxybenzoate, sodium methyl para-hydroxybenzoate, sulphur dioxide, sodium sulphite, sodium hydrogen sulphite, sodium metabisulphite, potassium metabisulphite, calcium sulphite, calcium hydrogen sulphite, potassium hydrogen sulphite, biphenyl (diphenyl)(phenylbenzene), orthophenyl phenol, sodium orthophenyl phenol, thiabendazole, nisin, natamycin, pimaracin, formic acid, sodium formate, calcium formate, hexamethylene tetiamine, hexamine, formaldehyde, dimethyl dicarbonate, potassium nitrite, sodium nitrite, sodium nitrate, saltpetre, potassium nitrate, acetic acid, potassium acetate, sodium acetates, sodium hydrogen acetate, calcium acetate, lactic acid, propionic acid, sodium propionate, calcium propionate, potassium propionate, boric acid, sodium tetiaborate, chorine, chlorine dioxide, invertase, and lysozyme.

Preferably a preservative is hydrogen peroxide which is volatile and has a short half life within the gel, preventing bacterial or microbe growth for the duration of the period that the gel is susceptible to such growth.

The gel may additionally comprise additives for pest control. Preferably additives for pest control are selected from copper particles or salt crystals and the like, for example useful to target slugs and snails.

The gel may additionally comprise additives to repel animals and birds. Suitable additives include substances forming repellent odours and the like. We have found that the gel according to the invention gives weed suppression, thereby reducing labour hours for weeding and simultaneously improving plant growth. Additional advantages include reduction in water or nutrient loss reducing labour hours for watering, reduction in pest and diseases since weeds provide host plants for pests and diseases. The invention also provides for better plant husbandry and better appearance at the point of sale. The reduced weed growth, pest and diseases also reduce labour hours and chemical costs in remedial spraying.

Finally the gel has an environmental aspect, and both gel form and residue form degrade and disperse totally after the period of 3-12 months whereby there is no need to remove the gel residue before planting out.

In an alternative embodiment of the invention the horticultural gel as hereinbefore defined is for use in preventing fluid loss from a living or cut plant or plant locus. In this embodiment the gel as hereinbefore defined may be applied to a soil surface as hereinbefore defined or may be applied to a water filled container, for example by filling a vase or the like for cut flowers.

In a further aspect of the invention there is provided a novel residue of the horticultural gel as hereinbefore defined comprising discrete or continuous residue, such as flakes or film, with a lower fluid content. It is thought that residue comprise residual gel content of greater than 40%, more preferably greater than 60%. Residue may serve some purpose as a barrier if directly applied.

In a further aspect of the invention there is provided a gelling material for a horticultural gel as hereinbefore defined comprising a mixture of two or more inert gelling component suitable for binding together to form a barrier to prevent germination of weeds.

In a further aspect of the invention there is provided a method for preparing a horticultural gel as hereinbefore defined comprising combining a gelling material with fluid in desired amount, blending and/or warming and/or boiling to dissolve and transferring to a mould, container or surface to set. Alternatively the method may comprise combining the gelling material with fluid, placing in a mould and then heating to set, for example in the case that gelling material is milk or egg protein. Alternatively the method may comprise combining gelling material with fluid, mixing with a setting agent and transferring to a mould to set, for example in the case that gelling material is alginate and setting material is a calcium source.

Gelling material is typically obtained in powder form. Preferably gelling material is commercially available. Agar is extracted from seaweeds, in particular from red- algae, and is commercially available. Gelatin is an animal extract and is commercially available. Other gelling materials are commercially available via trade or domestic sources.

The gel mixture may be placed into one or more shaped moulds, for example having an attractive shape for dispersing across a weed prone surface. Shapes include cubes, spheres, discs, polygonal blocks, and decorative shapes. Alternatively the gel mixture is applied to a suitable setting tray or surface and provided as a block or sheet of gel which may be mangled or worked to a pliable form at the time of application giving a semi-solid mixture or suspension of lumps of different shapes and sizes, which may be dispensed by measured scoop or the like. Alternatively the gel mixture is applied to a suitable setting tray or surface and provided as a block or sheet of gel which may be cut into polygonal blocks of 5mm to 40mm in any dimension.

Alternatively and preferably the gel mixture is transferred to a container and filled to exclude any air. We have found that sealed storage gives improved shelf life. Moreover this helps to keep the gel clean and sterile in a plant nursery environment, and aids speed and accuracy of application Preferably the container is suited for use as a dispenser or piping means, syringe or the like. The container may comprise a nozzle and plunger or may be assembled for use by attaching a nozzle and plunger means. Alternatively the container may be flexible and may comprise or be adapted for assembly with a nozzle whereby gel is extruded out by squeezing the container walls.

Preferably the container is of volume suited to dispense gel to a particular area, for example is of volume 25 ml, 100 ml, 250 ml, 500 ml or 1 litre.

In a particular advantage we have found that dispensed gel, from a gel block or container provides an improved film formation of desired thickness with use of less gel form material.

Additionally we have found that extruding gel from a syringe directly on to a weed surface reduces damage to the structure of the gel and prolongs the life of the gel while on the pot, compared with mangling or working a set gel layer to form a semi solid mixture of lumps of different shapes and sizes.

The gel may be made up with additional materials for example colourants, preservatives, fungicides, herbicides and the like as hereinbefore defined. We have found that applying environmentally acceptable colourants gives an attractive appearance to the gel. The gel may be provided in any desired volumes and is suitably made up in litre, half litre, quarter litre, 100 ml or 25 ml volumes. Gel shapes may be made up with desired volume and are typically made up in convenient dimensions of 5 mm - 40 mm in any dimension, for example 5 mm x 10 mm x 12 mm - 25 mm x 30 mm x 40 mm. Importantly the gel shapes or semi-solid gel of the invention are of sufficient size or cohesion to avoid being blown away or otherwise removed from the locus.

In a further aspect of the invention there is provided an applicator filled with gel as hereinbefore defined and comprising nozzle means and extrusion means or adapted to be fitted with nozzle means and extrusion means.

Preferably the gel applicator is reusable and may be returned to the manufacturer for cleaning and refilling. In a further aspect of the invention there is a therefore provided a method for filling a gel applicator with gel as hereinbefore defined, and/or for cleaning and refilling.

In a further aspect of the invention there is provided a method of application of a horticultural gel as hereinbefore defined. In a first embodiment, the method is for applying to a weed prone surface comprising obtaining gel and applying in desired thickness to the weed prone surface. A weed prone surface is typically selected from soil including any composts, fertilisers and the like. Application may be to the entire surface or part thereof, for example about emerging or protruding plants, or about any continuous cover means for dual form weed suppression.

The gel is applied to a suitable depth to degrade to form a film of 1 mm - 3 mm thickness. Preferably the gel is applied in a thickness from 8 to 10mm to 100mm as hereinbefore defined. For a typical 2 litre plant pot, gel may be used in an amount of half a litre of shaped (cubed) gel or mangled or extruded gel.

The gel is applied in solid or semi solid as hereinbefore defined, depending on the nature of the gel material employed and the desired mode of application. The gel may be provided as discrete shapes for example shaped blocks of suitable size for random scatter application. Alternatively gel may be provided as a gel body which may be pliable on application by mangling, working, extruding, cutting, shredding, tearing and the like to render in dispensable form. Gel may be applied manually or mechanically. Manual application may be by simply scattering or by dispensing from a suitable syringe or hose. Mechanical application may be by automated syringe, hose, shaker or the like.

In an alternative embodiment the method for application of the gel is for applying to a living or cut plant or its locus for fluid retention purpose. Gel shapes may be placed in a vase with water to support cut flowers. Different coloured gel shapes may be used in this way to give a decorative effect.

The gel may be used in association with additional materials or devices. In a preferred aspect of the invention the gel is applied in association with additional continuous covering means as bilayer or a co-continuous layer. Additional covering means may be any known existing or novel cover means, for example plastic, biodegradable plastic, fabric, card or paper sheeting or shaped inserts, shaped to fit standard size plant pots. Preferably the gel is used in conjunction with continuous inserts of the shape of a plant pot and having a square, circular, triangular, hexagonal or decorative shaped aperture in the centre through which a growing plant may emerge or protrude. The insert may be made as integral means for emerging plants or with a slit from aperture to outside edge on one or both sides to allow the insert to be slotted around the plant. The insert may comprise additional anchoring means such as a hole for spearing with a cane or stick, a rand for stapling or taping to a pot, or may be adhered by the insert gel bilayer.

When applied as a bilayer, the gel preferably adheres to the weed prone surface, i.e. compost soil or the like, the pot and the continuous cover means. Preferably however the combination is applied as a co-continuous layer, with the cover means located in place on the weed prone surface and gel applied at the central aperture around the emerging or growing plant and optionally additionally at the slit and edges. We found that the co-continuous layer with gel applied in the aperture gives an extremely effective weed suppression. The cover means may additionally be used for advertising purpose, for example may be printed up preferably in waterproof print.

When used in combination with a continuous cover means as hereinbefore defined the method comprises applying a cover insert to a gel layer, or applying the cover to the weed prone surface and applying gel at the apertures and optionally the opening slit and edges of the surface. In a particular advantage we have found that applying as a co-continuous layer in this manner requires application of gel in amount 20 ml reduced from half a litre.

Preferably the continuous cover means is degradable with time over a period of approximately 3-12 months, for example 3, 6 or 12 months, in keeping with the environmental concept of the gel as hereinbefore defined.

The method includes selecting the form of gel to be applied, for example shapes, gel body or gel comprised in applicator means. In a particular advantage we have found that applying gel in applicator means provides weed suppression for a period of up to 6 months during which gel degrades to film and film disperses. This is in contrast to applying a layer of shapes which provide protection for up to 3 months as gel, degrading to film and dispersing.

In a further aspect of the invention there is provided the use of a gel as hereinbefore defined in horticulture, being any domestic or commercial plant or crop related application, more preferably in weed suppression, moisture retention and the like.

The invention is now illustrated in non limiting manner with reference to the following examples and figures.

Example A - Preparation of Gel

Gel material in desired amount was added to deionised water or tap water in desired amount and heated for approximately 2 - 4 minutes or dissolved in hot water and left to stand, with optional stirring during the heating. Samples were made up as in the following examples

1) Water deionised ( ml ) 10 20 40

Agar ( gm ) 0.2 0.2 0.2

0.4 0.4 0.4

0.6 0.6 0.6

0.8 0.8 0.8

1 1 1

Heated for approx. 2mins

Allowed to set approx. 1 hour 2) Water deionised ( ml ) 15 Agar ( gm ) 1 Heated for approx. 2mins

Allowed to set approx. 1 hour in a petri-dish

3) Water deionised ( L ) ^XA Agar ( gm ) 6 Heated for approx. 4mins

Not allowed to set but applied directly

4) Tap water ( L ) V₂ Supercook Vege-gel ( gm ) 6 Dissolved in hot water and left to set

5) Tap water ( L ) Vi

Supercook Gelatine ( gm ) 11.7 Dissolved in hot water and left to set

6) Tap water ( L ) ^l YGS Gelatine ( gm ) 6

YGS Agar ( gm ) 6

Food colour (optional) 45-50 drops Heated in microwave for 4 mins ( Stirred after every 1 min ) then left to set

7) Tap water ( L ) ^lA

YGS Gelatine ( gm ) 6

YGS Agar ( gm ) 6

Food colour (optional) 45-50 drops Heated in microwave for 4 mins ( Stirred after every 1 min ) poured into a container approx. 1cm deep then left to set. Once set cut into 1cm x 1cm x 1cm squares

8) Tap water ( L ) ^lA

YGS Agar ( gm ) 6

Food colour (optional) 45-50 drops

Heated in microwave for 4 mins ( Stirred after every 1 min ) poured into a ice cube container approx. 1cm deep. Once set removed from tray and provided as ice cube shape or cut each ice cube shape into 4 smaller squares (7.5 mm x 8 mm x 5 mm) to aid application.

9) Gel make up / strength / appearance that is most effective at the moment - Tap water ( L ) ^XA YGS Agar ( gm ) 6

Food Colour (optional) 45-50 drops

Heated in microwave for 4 mins ( Stirred after every 1 min ) poured into a ice cube container approx. 1cm deep.

Once set removed from tray and provided as ice cube shape or cut each ice cube shape into 4 smaller squares ( 15mm X 8mm X 5mm ) to aid application.

10) Tap water ( L ) ^lA YGS Agar ( gm ) 3 YGS Gelatine ( gm ) 6 Food colour (optional) 45 - 50 drops

Added to cold water and heated in microwave for 3 mins without allowing to boil ( Stirred after every 1 min ) poured into a syringe and allowed to cool and set ready for dispensing. 11) Tap water ( L ) A

YGS Agar ( gm ) 10

Miracle-Gro^® or Phostrogen 5 tablespoons

Food colour (optional) 30 drops Heated in microwave for approximately 2.5 mins, poured into a ice cube container approx. 1cm deep.

12) Tap water (L) ^lA

YGS Agar ( gm ) 10

PEG 1000 (gm) 40

Food colour (optional) 30 drops

Heated in microwave for approximately 2.5 mins, poured into a ice cube container approx. 1 cm deep .

13) Tap water (L) ^lA YGS Agar ( gm ) 10

PEG 1000 (gm) 40

Food colour (optional) ^lA spatula

Hydrogen peroxide based bleach (ml) 20

Heated in microwave for approximately 2.5 mins, poured into a container approx. 1cm deep.

Once set cut into small cubes( 15mm X 8mm X 5mm ) to aid application. Comparative Example

A synthetic horticultural material comprising water storing granules (Swellgel) is available commercially for hydrating and use in aiding water storage in plant containers. When mixed with water Swellgel comprises hydrated particles of diameter approximately 2 to 5mm. Swellgel is usually mixed with compost, however in this example the hydrated particles were applied to the surface of compost in a pot in place of the gel of the invention to compare results. The treated pot showed very poor retention of the gel particles and after 1 month no gel remained, having been blown away or otherwise dispersed, possibly by biodegradation and weed growth had not been suppressed.

Example B - Application of gel to weed prone surface

Gel prepared by the above Examples was applied as follows, in each case applying gel to a thickness of 10 mm:

1, 4, 5, 6 - gel was mangled to a point where the gel became pliable to spread over surface of pot.

2 - circular gel plate was cut from dish to size of pot, and pierced with a knife to provide small drainage slots, then placed over the area of compost.

3 - gel was poured over a dormant host when still very hot. This left ( when cold ) a hard / solid surface.

7, 8, 9 - squares were applied to surface of compost in pots, about a protruding plant, as illustrated in Figure 1. Smaller squares allow easy application to pot and good depth / cover.

10 - gel was extruded from syringe over surface of compost in pot, about a protruding plant, as illustrated in Figure 2. Advantages of this method include use of lesser amounts of gel and less damage to gel structure. 11 - squares were applied to surface of compost in pots. Use of fertiliser in the gel mixture led to formation of a sealed skin on the gel surface. These gels demonstrated enhanced moisture retention.

12 - squares were applied to surface of compost in pots. Use of PEG led to enhanced moisture retention.

13 - squares were applied to surface of compost in pots. Use of bleach in the mixture helped to prevent bacteria contamination on the gel surface over time.

Example C - Preparation of Gel-Card Layer 14- Gel from Example AlO was extruded from a syringe, as shown in Figures 4 and 6, over the surface of compost in pot, about a protruding plant. A card pot cover in two hemispherical halves was placed on top of the gel about the protruding plant, locating the axial aperture thereabout. The advantage of this method is that the gel adheres the card to the compost surface. 15- A card pot cover in two hemispherical halves was placed about a protruding plant, locating the axial aperture thereabout. Gel from Example AlO was extruded from a syringe over the exposed surface of compost in pot, about a protruding plant, as illustrated in Figure 3. Advantages of this method include use of lesser amounts of gel, only 25 ml was required.

Example D - weed suppression

Pots were made up as described in Example B 1-10 and compared with controls. In each case the treated pots showed no weed growth for 3 to 6 month periods, compared to medium or profuse weed growth in controls. A plant free pot was made up half treated and half non treated, as illustrated in Figure 5, weed growth was observed in the non treated half only.

Trials show that pure agar with no gelatine lasts longer.

Further aspects of the invention will be apparent from the foregoing.

Claims

1. A horticultural gel comprising a solid or semi solid gel for use in horticultural applications, wherein the gel comprises gelling material in an amount of 8g or greater than 8g per litre fluid.

2. A gel as claimed in Claim 1 adapted to be applied as a weed- suppressing layer to a weed prone surface and to release fluid with time to form a residue in the form of a weed-suppressing residual layer, or to retain gel longevity of greater than 3 months.

3. A gel as claimed in any of Claims 1 or 2 comprised in gel body form, for example a gel block for cutting into smaller shapes, discrete gel shapes such as cubes, spheres, discs, polygonal blocks, decorative shapes and the like, or comprised in a container for extrusion as a semi solid mixture of gel lumps.

4. A gel as claimed in any of Claims 1 to 3 wherein discrete gel shapes are of size in at least one dimension in excess of 5mm.

5. A gel as claimed in any of Claims 1 to 4 comprising a chemically inert gelling material which is a hydrocolloid of animal, bird, mammal, plant, micro-organism or synthetic origin or a mixture thereof.

6. A gel as claimed in any of Claims 1 to 5 comprising an inert gelling component or a mixture of two or more inert gelling components which bind together to form a barrier to prevent germination of weeds.

7. A gel as claimed in any of Claims 1 to 6 wherein the gelling material is selected from gelatine, egg protein, milk protein, soy protein, gels based on edible gums or a blend of gums which include for example guar gum, xanthan gum, carrogeenan gum, carob gum, tara gum, konjac, cassia gum, polysaccharides such as extracts from algae, e.g. agar which is extracted from seaweeds, in particular red algae, alginate, furcelleran, pectin, cereal flours and starches, cellulose derivatives, chitin derivatives, bacterial fermentation gums such as gellan gum, polyvinylpyrrolidine, carbopol (a cross linked polyacrylic acid polymer) (BF Goodrich) and mixtures thereof.

8. A gel as claimed in any of Claims 1 to 7 comprising gelling material in an amount of 10 to 60g per litre fluid.

9. A gel as claimed in any of Claims 1 to 8 comprising from 33:67 to 50:50 by weight of agar: gelatin or gum

10. A gel as claimed in any of Claims 1 to 9 wherein the fluid component is water.

11. A gel as claimed in any of Claims 1 to 10 comprising a liquid fertiliser or salt containing agent, a humectant, a setting agent, a colourant, a growth promotion agent selected from herbicide, fungicide and growth promotor, an antibacterial or anti-microbial agent, additives for pest control or repellents for birds or animals.

12. A gel as claimed in any of Claims 1 to 11 wherein the gel is sterile and nutrient free.

13. A gel as claimed in any of Claims 1 to 12 having longevity of two to six months prior to residue formation and a further two to six months during which the residue remains intact.

14. A horticultural gel as claimed in any of Claims 1 to 13 for use in preventing fluid loss from a living or cut plant or plant locus.

15. A residue of a gel as claimed in any of Claims 1 to 14 comprising discrete or continuous residue with a residual gel content of greater than 40%.

16. A gelling material for a gel as claimed in any of Claims 1 to 14 comprising a mixture of two or more inert gelling components suitable for binding together to form a barrier to prevent germination of weeds.

17. A method of preparing a gel as claimed in any of Claims 1 to 14 comprising combining a gelling material with fluid, blending and/or warming and/or boiling to dissolve and transferring to a mould, container or surface and allowing to set.

18. A method as claimed in Claim 17 comprising combining the gelling material with fluid, placing in a mould and then heating to set.

19. A method of preparing as claimed in Claim 17 comprising combining gelling material with fluid, mixing with a setting agent and transferring to a mould to set.

20. A method as claimed in any of Claims 17 to 19 wherein transferring to a mould is to a shaped mould comprising shapes including cubes, spheres, discs and polygonal blocks of 5mm to 40mm in any dimension.

21. A method as claimed in any of Claims 17 to 19 wherein after allowing to set gel is cut into polygonal blocks of 5mm to 40mm in any dimension.

22. A method as claimed in any of Claims 17 to 21 wherein transferring is to a container and filling to exclude air.

23. A method as claimed in Claim 22 wherein a container is in the form of a dispenser, piping means, syringe or extruder.

24. An applicator filled with a gel as claimed in any of Claims 1 to 14 comprising nozzle means and extrusion means or adapted to be fitted with nozzle means and extrusion means.

25. A method for filling a gel applicator as claimed in Claim 24 with gel as claimed in any of Claims 1 to 14, and/or for cleaning and refilling.

26. A method of application of a gel as claimed in any of Claims 1 to 13 to a weed prone surface comprising obtaining gel and applying to a weed prone surface in a depth of approximately 8 to 100 mm.

27. A method as claimed in Claim 26 comprising extruding gel from a syringe directly onto a weed prone surface.

28. A method as claimed in Claim 26 or 27 comprising applying gel in association with additional continuous covering means as a bilayer or a co-continuous layer, for example plastic, fabric, card or paper sheeting or shaped inserts.

29. A method of application of a gel as claimed in any of Claim 14 to a living or cut plant or its locus.

30. A continuous covering means comprising a shaped card or paper insert having an aperture in the centre through which a growing plant may emerge or protrude optionally comprising a slit from aperture to outside edge on one or both sides.