GB2269378A

GB2269378A - Fibrous growth media

Info

Publication number: GB2269378A
Application number: GB9316293A
Authority: GB
Inventors: Christopher Parkinson
Original assignee: Courtaulds Chemical Holdings Ltd
Current assignee: Courtaulds Chemical Holdings Ltd
Priority date: 1992-08-05
Filing date: 1993-08-05
Publication date: 1994-02-09
Anticipated expiration: 2013-08-05
Also published as: GB9216625D0; GB2269378B; GB9316293D0

Abstract

Fibrous growth media having increased water retention consist essentially of a uniform mixture of a fibrous material and a water-soluble polymer such as carboxymethyl cellulose in addition to any conventional ingredients such as fertilisers. The growth media may be prepared by mixing the fibrous material with the water-soluble polymer as a solid or in aqueous solution. The fibrous growth media are useful for the cultivation of plants grown in them from seeds or cuttings or transplanted into them.

Description

FIBROUS GROWTH MEDIA This invention relates to fibrous growth media for plants, to methods of manufacturing such fibrous growth media and to methods of cultivating plants in such media.

Peat is defined as a material consisting mainly of dead plant organisms that have been transformed in a complicated, uncontrolled chemical process, largely under air exclusion and in the presence of excess water, i.e. bog conditions. This chemical process generally takes hundreds or thousands of years.

Peat is a fibrous material, fibres being the most rot-resistant part of the dead plant organisms. It has a high surface area, and its fibres are capable of interlocking to provide an excellent anchorage for plant root systems. Peat is often mixed with mineral fertilisers and trace elements to enhance its nutrient level, and it is widely used as a growth medium for plants. Peat is a natural resource which is only slowly renewed, and there is a desire to replace it or to supplement it by other materials which are more rapidly renewable resources.

Proposals have been made to use a variety of materials as substitutes for peat. Materials such as vegetable fibres, paper (especially waste paper), sawdust, bark, wood chips and rockwool have been suggested as fibrous growth media. Materials derived from plants may be composted before use as growth media. Coco peat (also known as coir dust) has been used as a substitute for peat in horticulture, particularly in the form of coir-based compost. It is obtained from coir, which is the fibre obtained from the shell of the coconut. All these materials are readily available, are fibrous in nature and resist rot. Those of the materials which are derived from plants are renewable resources and, after composting, are in many ways similar to peat.Such materials can be converted into usable composts by modern techniques in a few years or tens of years, certainly less than a hundred years, and such composts represent attractive substitutes for peat-based compost. Proposals have also been made to use mixtures of peat with materials such as pulverised fuel ash, for example in equal parts by weight, as plant growth media. However, all of these materials suffer from the disadvantage compared with peat itself that they have relatively poor water retention, and they are in consequence generally less satisfactory as plant growth media than peat. It is an object of the present invention to provide a means of increasing the water retention of plant growth media based on such materials, preferably to a level comparable with that of peat.

DE-A-1592790 describes the preparation of free-flowing peat and peat/fertiliser granules without the need for heavy-pressure equipment. Peat is shredded, mixed with chemical fertiliser or other additives in a screw-worm and passed into a rotary drum or tray in which it is sprayed with water. The moist mass is rolled into granules about 10 mm in size, which are classified, mixed in a drum with a dry adhesive which coats the surface of the granules, such as ethyl cellulose, carboxymethyl cellulose, alginate, dextrin or water-soluble starch, dried and packaged.

JP-A-2-117319 describes a culturing material obtained by kneading plant granules, a water-absorbing fibrous material, water, and a natural adhesive or an adhesive of a synthetic high molecular material, forming the kneaded mixture into a specified shape, and drying to solidify. The material preferably contains plant nutrients. Plant granules mentioned include wood chips, wood powder, cork granules, ground roots, stems and leaves of plants, and chaff granules. Water-absorbing fibrous materials mentioned include pulp, regenerated pulp, wool, silk, paper, rayon and cotton. Adhesives mentioned include casein, gelatin, starch, dextrin, hydroxyethyl cellulose, vinyl acetate, vinyl chloride and acrylic resins.

JP-A-54-015808 describes a lightweight, water-permeable medium for growing vegetables which comprises 100 parts crushed peat moss, 0.01-5 parts water-soluble organic polymer, 0.01-5 parts surfactant, and optionally a neutralising.;agent, all parts being by weight. The medium has high water-retaining property, fertiliser-retaining property, high water- and gas-permeability, high swelling property, and it can be shaped. Examples of watersoluble polymers mentioned include methyl cellulose, hydroxyethyl cellulose, poly(vinyl alcohol), starch and polyacrylic acid. Examples of surfactants mentioned include fatty acid salts, higher alcohol sulphuric acid esters, aliphatic amines, sulphates and aliphatic amides.

JP-A-51-013649 describes a culture medium for pot plants containing a mineral powder sprayed on humus, optionally together with a high molecular weight binder. Examples of humus mentioned are sawdust compost and straw compost. Examples of mineral powders mentioned are porcelain, bentonite and andesite.

Examples of high molecular weight binders mentioned are saponified poly(vinyl alcohol), carboxymethyl cellulose, agar, methyl cellulose and polyacrylate. The culture medium is suitable as a soil-like material for pots because it has good porosity and water retention.

The present invention provides in a first aspect a fibrous growth medium having increased water retention which consists essentially of a uniform mixture of a fibrous material and a water-soluble polymer, preferably a water-soluble cellulose ether, in addition to any conventional ingredients such as fertilisers and nutrients.

The invention provides in a second aspect a process for increasing the water retention of a fibrous growth medium wherein the fibrous growth medium is uniformly mixed with a water-soluble polymer, preferably a water-soluble cellulose ether, either alone or concurrently with conventional ingredients such as fertilisers and nutrients. The water-soluble polymer may be utilised in the form of a solid or of an aqueous solution.

The invention provides in a third aspect a method for the cultivation of plants, wherein the plants are grown from cuttings or seeds in a fibrous growth medium according to the first aspect of the invention or prepared according to the process of the second aspect of the invention.

The invention provides in a fourth aspect a method for the cultivation of plants, wherein the plants are transplanted into and grown in a fibrous growth medium according to the first aspect of the invention or prepared according to the process of the second aspect of the invention.

The fibrous material is a material other than conventional peat compost, which consists essentially of peat and in general has satisfactory water retention characteristics.

In one embodiment of the invention the fibrous material is a cellulosic material. Preferred examples of cellulosic material include material derived from wood, for example sawdust, bark, wood chips and paper, especially waste paper. Other examples of cellulosic material include natural and synthetic cellulosic fibres, for example cotton or rayon, and shredded regenerated cellulose film. The fibrous material may be such a cellulosic material which has been composted. A particularly preferred example of a cellulosic material is coir, especially in the form of coco peat or coir compost. It will be noted that these cellulosic materials are rapidly renewable natural resources.

It will also be noted that many such cellulosic materials are byproducts or waste products, and accordingly the growth medium of the invention provides a means for utilising or recycling such materials. In another embodiment of the invention the fibrous material is a mixture of peat with a substantial proportion of an inorganic material with poor water-retention properties, for example pulverised fuel ash, for example in a weight ratio of about 1:1, or rockwool, for example in a weight ratio of about 10:1 to 1:1. Mixtures of more than one type of fibrous material may be used. The fibrous growth medium of the invention may be mixed with other growth media, for example peat. Plant nutrients, for example fertilisers and trace elements, may be added to the growth medium of the invention.

The water-soluble polymer is preferably a water-soluble cellulose ether. Examples of water-soluble cellulose ethers include methyl cellulose, hydroxyethyl cellulose, hydroxyethylmethyl cellulose, ethylhydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, and especially carboxymethyl cellulose (CMC). CMC is generally available commercially in the form of its sodium salt. It is thought that ionic water-soluble cellulose ethers, for example CMC, may possess advantages over non-ionic cellulose ethers. Dry films of non-ionic cellulose ethers are generally more difficult to wet and therefore have a slower rate of water uptake than similar films of CMC. The growth media of the invention generally have a satisfactory rate of water uptake when CMC is used.A further advantage of CMC is that it is relatively inexpensive compared with other water-soluble cellulose ethers. CMC for use in the invention preferably has a degree of substitution (D.S.) in the range 0.4 to 1.1, more preferably 0.5 to 0.9. Technical or purified grades of cellulose ethers may be used. Technical grades of CMC contain appreciable proportions of free salts, in particular sodium chloride and sodium glycollate. The watersoluble polymer is preferably biologically degradable at a slow rate, for example over several months or a few years. The increased water retention provided by the invention is generally lost if the polymer is degraded, for example by bacterial attack.

Cellulose ethers are generally biologically degraded in the fibrous growth media of the invention at a satisfactory slow rate. Naturally-occurring water-soluble polysaccharides such as starch or guar gum may be used in the invention, but they are generally less preferred since they are liable to rapid degradation by bacterial attack. Derivatives of such natural polysaccharides which are less subject to bacterial attack, for example etherified derivatives, may be used in the invention.

Fully synthetic water-soluble polymers such as poly(vinyl alcohol) or poly(acrylamide) may be used in the invention, but they are generally less preferred because of their resistance to biodegradation.

The water-soluble polymer preferably has low toxicity properties, particularly if it is intended to use the growth medium of the invention for the cultivation of plants for human or animal consumption. The abovementioned water-soluble polymers, in particular the cellulose ethers, are available commercially with low toxicity properties.

The water-soluble polymer preferably has a viscosity in the range 5 to 10000 centipoise measured on a 1% by weight aqueous solution, more preferably in the range 5 to 100 centipoise, further preferably in the range 10 to 25 centipoise. The viscosity is measured under low-shear conditions at ambient temperature on the technical or purified material as supplied.

It is known that the optimum maximum electrical conductivity of a plant growth medium such as a compost is preferably 200 pS/cm for seed sowing, 450 pS/cm for potting and 600 pS/cm for mature plants, although values up to about 100 pS/cm higher than these are nevertheless acceptable. Technical grades of CMC contain free salts, in particular sodium chloride and sodium glycollate. Addition of technical CMC to a plant growth medium therefore raises the electrical conductivity of the growth medium. Care should therefore be taken to ensure that the electrical conductivity of the growth medium of the invention is within acceptable limits for the desired end-use. Purified grades of CMC contain only low levels of such salts.

The preferred amount of water-soluble polymer in the growth medium of the invention depends to some extent on the nature both of the water-soluble polymer and of the fibrous material, on the type of plants to be grown and on the stage in the life of the plants. The most appropriate amount of water-soluble polymer for any particular combination can readily be determined by growing trials. The amount of water-soluble polymer is generally about 0.1 to about 5.0 kgm , preferably about 0.1 to about 1.0 kgm more preferably about 0.25 to about 0.5 kgm 3 of the growth medium. The volume of the growth medium is assessed on the medium in loose and uncompressed form suitable for the cultivation of plants.These values have in particular been found to be suitable when the water-soluble polymer is CMC, particularly when the fibrous material is coco peat.

The growth medium of the invention has an increased water retention measured according to British Standard 4156:1990 compared with the fibrous material alone, preferably increased to a level comparable to that of peat. The water retention of the growth medium of the invention is preferably at least 170% w/w, more preferably at least 175% w/w, further preferably at least 180% w/w. The water retention of the growth medium of the invention is preferably less than 210% w/w, more preferably less than 205 or 200% w/w. The water retention of the fibrous material for use in the growth medium of the invention is generally less than 170% w/w and may be less than 165% w/w.

The growth medium of the invention has an increased waterholding capacity (water retention measured according to British Standard 4156:1990 and expressed on a weight/volume basis) compared with the fibrous material alone, preferably increased to a level comparable to that of peat. The water-holding capacity of the growth medium of the invention is generally at least 65% w/v, preferably in the range 65 to 75% w/v. The waterholding capacity of the fibrous material for use in the growth medium of the invention is generally less than 65% w/v and may be less than 60% w/v.

The growth medium of the invention generally has a reduced air-filled porosity measured according to British Standard 4156:1990 compared with the fibrous material alone. The airfilled porosity of the growth medium of the invention is preferably in the range 9 to 15% v/v, more preferably 11 to 13.5% v/v. The air-filled porosity of the fibrous material for use in the invention is generally at least 14% v/v. The air-filled porosity of the growth medium of the invention generally corresponds to ADAS Index 2 (ADAS is the Agricultural Development and Advisory Service of the Ministry of Agriculture, Fisheries and Food). ADAS Index 2 growth media are generally recommended as suitable for pot and foliage plants, bedding plants and nursery stock in small to medium pots.Such growth media are relatively free-draining and are noted for having less critical water-management requirements than other growth media.

The growth medium of the invention may be prepared according to the process of the second aspect of the invention by mixing the fibrous growth medium and the water-soluble polymer together.

Water-soluble polymers are generally available commercially in the form of powder, and in one embodiment of the process of the invention the fibrous material is mixed with the polymer in powder form. In another embodiment of the process of the invention, the fibrous material and polymer are mixed by treating the fibrous material with an aqueous solution of the polymer.

This latter embodiment may be preferred, since it may be easier to achieve thorough and uniform mixing when it is used. The treatment may be accomplished by mixing the solution into the fibrous material or by spraying the solution onto the fibrous material. The concentration of the polymer solution may for example be in the range 0.5 to 5.0% by weight, preferably 1.0 to 2.0% by weight. Polymer viscosity and solution concentration are generally selected for convenience in handling and application of the solution, lower viscosity solutions being easier to handle and to apply. The amount of polymer solution may conveniently be in the range 15 to 30 litres per cubic metre of uncompacted fibrous material.The water-soluble polymer may be mixed with the fibrous material either dry or in solution either alone or concurrently with conventional fertilisers or other nutrients, and this latter method may be preferred, particularly if all the materials to be added are in aqueous solution or suspension. The mixed product is ready for use as the growth medium of the invention, and it does not require granulation, pressing or drying. It may nevertheless be preferred to dry the growth medium for storage when the solution treatment method is employed.

The growth medium of the invention is useful for the propagation of seeds and cuttings and for the cultivation of plants in pots. The growth medium of the invention is generally useful as a substitute for peat in domestic and commercial agriculture and horticulture. The growth medium of the invention can be used for tree planting. The increased water retention of the growth medium of the invention imparts "easy care" properties to plants growing therein, in that the plants require less frequent watering. This is a particular advantage when plants are grown to be sold from shops such as supermarkets, where the plants may be required to thrive without watering for up to 28 days.

The invention is illustrated by the following Examples.

Example 1 The rot-resistant fibrous material used in this Example was Wessex Seed and Potting Coco Compost, supplied by Wessex Horticultural Products Limited, of South Newton, Salisbury, Wiltshire. This compost consists of coco peat and a balanced blend of essential nutrients and trace elements.

The water-soluble polymer used in this Example was sodium carboxymethyl cellulose available from Courtaulds plc under the Trade Mark 'Courgel'. The polymer used was provided in the form of a powder, and is specified as having an activity of 67% as CMC and a viscosity of 12-20 centipoise measured by Ostwald U-tube on a 1% solution in water at ambient temperature.

The fibrous material and polymer were mixed together either by spraying a solution of polymer onto the fibrous material (for the lower addition rates) or by thorough dry mixing (for the higher addition rates). The water retention (WR, in percent weight/weight) and air-filled porosity (AFP, in percent volume/volume) of each sample were measured according to British Standard 4156:1990. Water-holding capacity (WHC, in percent weight/volume) was calculated from the measurements taken in the water-retention test.

An untreated peat compost was used in a comparative experiment. The compost used was Solo Multi-purpose Compost, supplied by White Moss Peat Company Limited, of Simonswood Moss Works, North Perimeter Road, Kirkby, Liverpool. This compost consists of a blend of sphagnum moss peat (black peat), perlite, ground magnesium limestone, fertiliser and trace elements.

Plant growth trials were conducted as follows. Fibrous growth medium was placed in each of ten seed trays, and each tray was sown with exactly 100 seeds of the radish variety French Breakfast. The trays were then watered as required to produce the correct growing conditions for the seed. Plants began to emerge after 6 days. The plants were counted after 10 days, and the percentage germination was calculated. Once the plants had reached the true two-leaf stage, 10 plants were taken at random and potted into 75 mm plastic pots using the same fibrous growth medium. The pots from all the experiments were arranged in a greenhouse using a randomised block design to minimise any effect of pot position in the greenhouse. The pots were then watered as required, and the plants were grown until they had produced an edible root.Leaf number (the total number of true leaves per plant), leaf size (the length in mm from the petiole to the tip of the eldest true leaf), and leaf colour were measured at 5 weeks after planting, and the average values were calculated.

Leaf colour was assessed on a scale of 1 (yellow, and undesirable) to 9 (green, and desirable). Root weight (the weight in g of the root as it would be sold) was measured at harvest, approximately 8 weeks after planting, and the results were averaged.

The results obtained are tabulated below: Ref. C"C WR W8C AFP Germ. Leaf Leaf Leaf Root kgm O Number Size = Colour Weight g Contml 0 166 58.9 14.0 94.8 3.1 34 8.1 3.2 6 0.5 170 60.6 13.2 94.1 3.4 51 8.4 3.3 7 1.0 183 65.2 13.4 95.8 3.2 59 8.2 7.4 8 2.5 203 72.1 12.4 96.1 3.4 50 8.9 6.5 9 5.0 211 75.1 11.8 95.1 3.1 45 7.9 4.1 10 10.0 221 78.6 6.2 96.2 3.2 37 8.3 4.2 Peat 0.0 172 69.0 9.0 95.2 3.4 30 8.4 3.4 The WR and WHC of the coir compost rose and the AFP fell as the addition rate of CMC was increased. The WR and WHC of compost reference 10 were considered to be too high and the AFP too low, and in consequence the plants were grown in a compost which was in effect waterlogged and the plants were in effect over-watered. Compost reference 9 was considered marginal in this context. Percentage germination and the length of time from sowing to germination were similar in all cases. There was no evidence in any case of phytotoxicity to the radish plants, and in particular there was no evidence of any chlorosis, necrosis or deformation.

Addition rates of 0.5-5.0 kgm3 gave the largest leaves.

Addition rates of 1.0-2.5 kgm3 gave a water-holding capacity comparable with peat and gave the largest radish roots. The addition rate of 1.0 kgm3 was considered to give the best results. The addition rate of 10 kgm-3 gave generally less satisfactory results.

Example 2 Example 1 was repeated, except that Tomato plants (Moneymaker, Lot No. 3225) were grown from seed. The following results were obtained: CMC3 Germination % Height Leaf Leaf kgm 3 7 days 14 days 21 days mm Number Colour 0.0 25.2 89.0 98.0 188.0 4.8 5.7 0.5 25.3 86.7 97.0 212.5 6.0 5.6 1.0 26.5 90.4 97.5 197.5 5.8 6.3 Germination rate and total germination were similar in all cases. Plant height after 50 days was significantly higher in the growth medium of the invention than in the control.

Leaf number and colour generally increased with increasing level of CMC in the growth medium, but not to a statistically significant extent. There was no evidence for any phytotoxic effect in any trial.

Example 3 Example 1 was repeated, except that ICI Multi-purpose Coconut Fibre Compost was used and Salvia plants were grown from seed. The compost as supplied had a conductivity of 324 pS/cm. The following results were obtained: CMC 3 Germination % Height Vigour kgm 7 days 14 days 21 days 28 days mm 0.0 6.1 51.5 75.7 81.5 102.1 7.5 0.5 1.9 46.8 71.9 80.4 77.9 8.7 Vigour was assessed on an arbitrary scale from 1 (dead) to 9 (perfect health). There was no evidence for any phytotoxic effect. Germination rate and total germination were similar in both cases. The plants grown in the growth medium of the invention were smaller but more healthy than plants grown in the untreated compost. Seeds planted in a compost containing 1.0 kgm 3 CMC failed to germinate.

Example 4 Example 3 was repeated, except that Tomato plants were grown from seed. The following results were obtained: CkMC3 7 days Germination % Height Vigour kgm-3 7 days 14 days 21 days 28 days mm 0.0 3.0 31.9 72.2 88.5 129.0 5.9 0.5 0.8 24.6 63.0 86.6 104.5 6.9 There was no evidence for any phytotoxic effect.

Germination rate and total germination were similar in both cases. The plants grown in the growth medium of the invention were smaller but more healthy than plants grown in the untreated compost. Seeds planted in a compost containing 1.0 kgm 3 CMC did not germinate satisfactorily.

Example 5 Example 3 was repeated, except that Wallflower plants were grown from seed. The following results were obtained: CMC Germination % Height Vigour kgm 3 7 days 14 days 21 days 28 days mm 0.0 0.0 41.0 79.7 90.6 33.1 6.2 0.5 0.0 40.5 77.2 90.6 20.8 7.0 1.0 0.0 13.0 33.3 58.5 12.4 5.7 There was no evidence for any phytotoxic effect.

Germination rate and total germination were similar in both cases. The plants grown in the growth medium of the invention containing 0.5 kgm3 CMC were smaller but more healthy than plants grown in the untreated compost. Results were unsatisfactory with this plant type in the growth medium containing 1.0 kgm CMC.

Claims

1. A fibrous growth medium having increased water retention which consists essentially of a uniform mixture of a fibrous material and a water-soluble polymer in addition to any conventional ingredients.

2. A growth medium according to claim 1, wherein the water soluble polymer is a cellulose ether.

3. A growth medium according to claim 2, wherein the cellulose ether is carboxymethyl cellulose.

4. A growth medium according to claim 3, wherein the carboxymethyl cellulose has a degree of substitution in the range 0.4 to 1.1.

5. A growth medium according to claim 4, wherein the carboxymethyl cellulose has a degree of substitution in the range 0.5 to 0.9.

6. .A growth medium according to any preceding claim, wherein the viscosity at ambient temperature of a 1 percent by weight aqueous solution of the water-soluble polymer measured under low-shear conditions is in the range 5 to 10000 centipoise.

7. A growth medium according to claim 6, wherein the said viscosity is in the range 5 to 100 centipoise.

8. A growth medium according to claim 7, wherein the said viscosity is in the range 10 to 25 centipoise.

9. A growth medium according to any preceding claim, which has a water retention measured according to British Standard 4156:1990 of at least 170 percent by weight.

10. A growth medium according to claim 9, wherein the said water retention is at least 175 percent.

11. A growth medium according to claim 10, wherein the said water retention is at least 180 percent.

12. A growth medium according to any one of claims 9 to 11, which has a water retention measured according to British Standard 4156:1990 of less than 210 percent by weight.

13. A growth medium according to claim 12, wherein the said water retention is less than 205 percent.

14. A growth medium according to claim 13, wherein the said water retention is less than 200 percent.

15. A growth medium according to any preceding claim, wherein the water retention of the fibrous material measured .according to British Standard 4156:1990 is less than 170 percent by weight.

16. A growth medium according to claim 15, wherein the said water retention is less than 165 percent.

17. A growth medium according to any preceding claim, which has an air-filled porosity measured according to British Standard 4156:1990 in the range 9 to 15 percent on a volume/volume basis.

18. A growth medium according to claim 17, wherein the said air-filled porosity is in the range 11 to 13.5 percent.

19. A growth medium according to any preceding claim, wherein the fibrous material has an air-filled porosity measured according to British Standard 4-156:1990 of at least 14 percent on a volume/volume basis.

20. A growth medium according to any preceding claim, wherein the fibrous material is a cellulosic material.

21. A growth medium according to claim 20, wherein the cellulosic material is coco peat.

22. A growth medium according to any one of claims 1 to 19, wherein the fibrous material is a mixture of peat with a substantial proportion of an inorganic material with poor water-retention properties.

23. A growth medium according to claim 22, wherein the inorganic material is pulverised fuel ash.

24. A growth medium according to any proceding claim, wherein the amount of the water-soluble polymer is in the range of about 0.1 to about 5.0 kg per cubic metre of the growth medium.

25. A growth medium according to claim 24, wherein the said amount is in the range of about 0.1 to about 1.0 kg per cubic metre.

26. A growth medium according to claim 25, wherein the said amount is in the range of about 0.25 to about 0.5 kg per cubic metre.

27. A method for the manufacture of a growth medium according to any preceding claim, wherein the water-soluble polymer in solid form is uniformly mixed with the fibrous material.

28. A method for the manufacture of a growth medium according to any one of claims 1 to 26, wherein an aqueous solution of the water-soluble polymer is uniformly mixed with the fibrous material.

29. A method according to claim 28, wherein the concentration of the water-soluble polymer in the aqueous solution is in the range 0.5 to 5.0 percent by weight.

30. A method according to claim 29, wherein the said concentration is in the range 1.0 to 2.0 percent by weight.

31. A method according to any one of claims 27 to 30, wherein the water-soluble polymer is mixed with the fibrous material concurrently with one or more conventional fertilisers.

32. A method for the cultivation of plants, wherein the plants are grown from cuttings or seeds in a fibrous growth medium according to any one of claims 1 to 26 or prepared according to any one of claims 27 to 31.

33. .A method for the cultivation of plants, wherein the plants are transplanted into and grown in a fibrous growth medium according to any one of claims 1 to 26 or prepared according to any one of claims 27 to 31.

34. A fibrous growth medium having increased water retention, substantially as described with reference to any one of the accompanying Examples.

35. A method for the manufacture of a fibrous growth medium having increased water retention, carried out substantially as described with reference to any one of the accompanying Examples.

36. A method for the cultivation of plants in a fibrous growth medium having increased water retention, carried out substantially as described with reference to any one of the accompanying Examples.