GB2294257A

GB2294257A - Growing media

Info

Publication number: GB2294257A
Application number: GB9521355A
Authority: GB
Inventors: Robert Alan Brooke Vese Stoney
Original assignee: CERES HOLDINGS Ltd
Current assignee: CERES HOLDINGS Ltd
Priority date: 1994-10-19
Filing date: 1995-10-18
Publication date: 1996-04-24
Also published as: AU3659395A; GB9421068D0; GB9521355D0; WO1996012687A1

Abstract

A growing media comprising food processing waste and a matrix material e.g. bark and coir. The growing media are suitable for use as a multi-purpose compost for plants. The food processing waste is preferably de-watered effluent from cheese processing, the matrix material is composted prior to mixing with the waste and the waste and matrix material are co-composted.

Description

GROWING MEDIA The present invention relates to growing media and in particular to a nutrient base for planl growing media and a method of making toe same.

It is known to make growing media from peat. I-lowever, peat-based media are unsatisfactory in a number of respects. For example, peat's water-holding capacity is poor aiid there is increasing opposition to peat-extraction from environmentalists.

In view of the above problems with peat-based growth media there has been increasing interest in alternative peat-fiee growing media.

Organic material such as that derived from sewage and the like is advantageous in that it provides a balanced range of nutrients. However, many such materials have a high pathogen content and heavy-metal contamination. In particular, any materia! known to contain sewage has a poor public image.

Vegetable transplant production is an important method of screening and evalualing the constituents of growing media. The use of cellular trays for the propagation of vegetable transplants is a well established procedure for commercial growers in the UK and elsewhere. Because of the small cell volume used with this system and the large amounl of nutrients the plant will require over the propagating/growing period. il is difficull, especially when using organic nutrients, to supply all the plant nutrients required by including them in the substrate formulation from tlie start in aii available (water soluble) form, as this would be toxic to the scedlings.

l1oe conventional system uscs growing media (usually peat-based) wliich contain all the nitrogen phosphate potassium and macronutrients required for seedling growtll. As the secdlillg becomes a small plant (a transplant) a liquid feeding regime starts which provides the rest of the nutrients required for growth. This avoids nutrient levels reaching phytotoxic proportions at any time during the propagation and seedling growth period.

Organically derived nitrogen has an available component and a reserve component.

Nitrogen is transferred from "reserve" to "available" by a process called nitrogen mineralisation. Only when nitrogen is mineralised can it be absorbed and utilized by plants. In an organic growing medium the relative proportions of reserve and available nitrogen and the speed al which mineralisation can take place are more important than levels of total nitrogen.

The system of growing is used on an experimental basis as it rapidly gives an indication as to the rate at which organic growing media run out of nutrients, as well as providing a measure of the suitability of the formulations to grow vegetable transplants from seed.

Typically, growing media made with an organic nutrient base are adversely affecled by irrigation or surplus overhead waiering as with the average user applying water with a watering can or hose. All the soluble, in other words available, nutrients, particularly nitrogen, can be flushed or leached out resulting in starved plants and poor growth.

Typically, the seed germination perfoniiance of growing media with an organic nutrient base is poor. The high sall concentration created by the presence of organic nutrients has an inhibitory effect on seed germination and seedling root growth. A means of proleclion from this effect has never before been built into an organic growing medium.

The present invention ainls lo provide an organic peat-free nutrient base, a multipurpose growing medium and a method of making tile SEUllC which does not suffcr from lhc above problems.

As used herein, the temi "growing medium" means a material capable of sustaining plant or root growth.

The term "nutrient base" is used herein to mean the nutrient-supplying component of a growing medium. In an inorganic growing medium the base is normally a synthetic granular composition containing nitrogen phosphate and potassium salts and trace elements, which usually takes up less than 1% of the total volume of the medium. By contrast in an organic growing medium the nutrient base is typically a bulky material such as composted animal manure.

The term "matrix material" is used herein to mean the substrate with which a nutrient base is mixed. This material dictates the physical properties of the growing medium, for example its water permeability [or percolation index (PI)], and its air to water content [or air-filled porosity (AFP)].

According to the invention, there is provided a growing medium comprising a nutrient base derived from food processing effluent, mixed with a matrix.

A wide variely of food processing effluent materials may be utilised in tile invention. Such materials include meat wastes, including abattoir wastes, and vegetable processing wastes. Other suitable effluent materials include wastes from industrial fermentation processes, such as yeast production. However, the presently preferred effluent material is dairy waste. Mixtures of such wastes may also be used.

Preferably, tloe effluent is de-watered to form a sludge. Most preferably, the eSucllt is biologically activated, by the maintenance of organisms and conditions (preferably aerobic) suitable for the biodegradation of a sludge waste. Such activation may take place in any conventional reactor/fermenter, eg "fluidised bed", "stirred tank", "air-lift" or "fixed film" designs.

Most preferably, the effluent is subjected, prior to any biological activation, to secondary sewage treatment. For dairy wastes, such treatment may take place in an oxygenated pond in which the particulate and dissolved organic solids are broken down aerobically. After settling, a sludge is obtained and it is this that is fed to the biological activation reactor.

Preferably, the matrix is bark and/or coir-derived material.

Preferably the bark is in the fonn of small chips, granules. or shreds, conveniently derived from coniferous species of trees such as spruce, larch or pine trees.

Advantageously the bark is matured, aged or coinposted prior to mixing with the effluent material. Optionally, a nitrogen source such as poultry manure is added to facilitate the maturing, ageing, composting process, prior to mixing with tile effluent malerial.

Advantageously fibres and/or granular dust from the husk of coconuts, or the residue from the production of coconut fibre referred to herein as coir-derived material, is iiicluded. Inclusion of coir improves the handling and composting properlies of the nutrient base.

Preferably dairy waste comprises effluent from cheese and/or whey processing.

The emuent is preferably subjected to conventional primary and secondary sewage treatment wllicll preferably includes a biological aclivation process to produce a nutrient-rich, activated effluent having approximately 2% solids content. The solids contclll is advantageously increased by de-watering to produce a sludge having a solids content of niore than 10% and preferably 14-30%.

Preferably. the effluent material nutrient base of the growing medium comprises dairy waste co-composted with bark, and optionally coir, and/or another peat-free matrix or nutrient material such as chopped straw, leaf litter, paper waste, wool waste, spent mushroom compost etc.

In another aspect the invention provides a method of producing a growing medium comprising mixing a nutrient base of material derived from food processing effluent with a matrix material which is preferably bark and/or coir and/or another peat-free matrix or nutrient material such as chopped straw, leaf litter, paper waste, wool waste, spent mushroom compost etc. Advantageously the bark is matured, aged, or composted prior to mixing with the dairy waste.

Preferably, the components of the medium are mixed, conditioned and stabilised by co-conlposting, the conlposting process advanlageously being carried out under aerobic conditions.

Preferably, wetted coir is added prior to composting.

I)referably, the composting process is carried out until the temperature of the material has stabilised. Temperature stabilisation is when the temperature of the material no longer exceeds 43 C within 72 hours of being disturbed as a routine procedure in the coniposting process. At this point it is deemed to be fully conditioned. When the composting process employs conventional mechanically turned windrows. a conditioning time of approximately 6 to 8 weeks is typical.

In a preferred method the co-composted growing medium produced is utilised as a nutrient base for a growing medium. To make the growing medium, the nutrient base is mixed with a matrix material, preferably coir or coir-derived material to which may be added other non-peat matrix materials such as sand, loam, perlite, vermiculite. zeolite and certain crop-plant residue products such as leaf-litter, straw products coffee waste, cocoa shells etc.It can then be milled and screened to standard specifications for a multi-purpose compost and packaged, as desired.

The usefulness of food processing waste, such as dairy waste, as a nutrient source in a composted growing medium is unexpected because one would predict that its greasy globular nature would make it very difficult, if not impossible to compost.

The growing media of tile invelltioll have an excellent nutrient supplying capacity and do not suffer from the aforementioned disadvantages of known growing media and in particular, those of organic peat-based and sewage-based growing media.

Optimising the quantities of nutrients in growing media is a notoriously difficult operation, especially when the growing medium is required for multipurpose use.

Too little nutrient and plants starve, loo much nutrient and the salinity levels rise rapidly to phytotoxic levels. The present invention permits the addition of unusually Iiigh proportions of nutrient with no adverse effect on germination and plant growth at salinity levels ( > 800 S/cm ) that in other growing media would result in severe phytotoxicity.

Another major advantage of the growing media of the invention is that nutrients are not susceptible to leaching. This may be due to the fat conient of the food processing waste and the particular way in which the composted residuc of the fat is integrated with the matrix, preventing nutrients from being flushed out or leached by excessive watering.

The growing iioedium of the invention is suitable for seed sowing, rooting cuttings, container growing. and in general purpose garden use.

I"lie addition of matrix material such as bark to tile food processing waste also has the advantage of eliminating or reducing noxious odours from the waste. As such, suclo matrix material is useful as a means of waste treatment. irrespeclive of subsequent use of the combined material.Thus, according to a further aspect of the present invention. there is provided a method for the treatnoent of food processing effluent, which method comprises mixing tloe effluent with a matrix as described above.

Preferred embodimollts of the invention will now be described, by way of example only, with reference to the following figures: Figure I shows the results of cabbage and lettuce assessments of growing media of the invention comprising a nutrient base of co-composted dairy waste and bark; and Figure 2 shows the results using the same indicators of growing media of the invention comprising a nutrient base of co-composted dairy waste, bark and coirderived material.

Production of growing media of the invention Ingredients: Nutrient base De-watered dairy-waste from cheese processing.

Matrix material Coniferous species bark (Spruce/pine).

Fibre and granular dust from coconuts (coir-derived material).

Process: Stage I Production of Nutrient Base. Effluent from cheese processing undergoes standard primary and secoiidary treatment to produce an activated, nutrient-rich effluent will approximately 2% solids. [ The solids are concentrated by a mechanical dc-watering process to produce a sludge of approximately 10-35% dry matter.

The sludge is combined with bark at source. as it is removed from the de-watering process. this is because bark lias the added benefit of acting as an absorbent and bio-filter to absorb ammonia and noxious putrescent odours such as hydrogen sulphide gas. Without the bark for this purpose, any handling of the sludge material once it starts to putrefy, and consequent disturbance ofthe noxious odours, poses a serious olfactory pollution threat and, more seriously, a health threat to operatives from ammonia and volatile ammonia-based compounds.

Advantageously the inclusion rate of bark with the dairy-waste-sludge is between 1:4 and 2:1 parts of bark to parts of dairy-waste-sludge, as measured by volume.

Preferably the bark and the sludge are mixed at a ratio of 1:1.2.

The bark and dairy-waste-sludge mix inlay be augmented, with other nonpeat matrix and/or nutrient base materials.

Similarly the nutrient content of the nutrient base may be augmented, when and wherever levels of such nutrients are deemed to be sub-optimal, by the addition of organically-permitted materials such as dried blood, hoof and horn, bonemeal, fish meal, seaweed and trace element supplements elc. The foregoing also applied to Stage 2 and Stage 3 below.

Stage 2 Conditioning Phase. The dairy-waste-sludge and chippedshredded/granulated bark combination is co-composted with wetted coirderived material. The inclusion rate of the coir-derived material at this stage can vary according to inconsistencies from one batch of bark and sludge and the next in their physical and chemical composition (for example moisture content and nitrogen levels respectively). Values for the moisture coniellt of the materials are important, as this directly affects the proportion of air available to initiate the composting process.

Advantageously the inclusion rate of coir-derived material (C) with the dairy-waste-sludge+liark (DB) is between, 12(twelve) : : (one) parts of DB to parts of C and, 1(one) : 1.5(one and a half) parts of DB to parts of C, as measured by volullle.

Preferably, and given optimum moisture and other levels, the inclusion rate is.

2(two) : I (one) parts of DB to parts of C, as measured by volume.

The coir-derived matrix material may be augmented at Stage 2, with other non-peal nlalrix materials sucli as those mentioned previously. The same applies to Stage 3 below.

The composting process is aerobic (mechanically turned windrows although an identical finished product could be obtained with other aerobic composting methods and systenls, eg, by using in-vessel compost reactors) and deemed fully conditioned when the temperature of the material has stabilised. Temperature stabilisation is when the temperature of the material no longer exceeds 43 C within 72 hours of being disturbed as a routine procedure in the conlpostillg process. Advantageously the conditioning time should be four to ten weeks, depending on ambient temperature, and preferably the conditioning time is six to eight weeks.

Stage 3 Blending, milling, screening aid bagging. The coin posted material is blended with a further addition of coir-derived material to create a range of growing media products, or, bagged without any further additions to create a range of soil improver products, noininally styled: "tree and shrub starter". "rose feed". "plant feed". "sports turf top dressing", "rrot zone mix", etc. The latter two products may be mixed with sharp sand at various inclusion rates according to the specifications required. Tlic prillcipal growing meduim is a multipurpose compost.

The most advantageous foriitilation for the multipurpose compost, as indicated from the performance trial evaluations, is an inclusion rate of coir-derived material (C) will tile coinl)osted d dairy-wastesludge+bark+coir (CDBC) of between.

5(five) : I(ollc) parts of C to parts of CDBC and, I (one) : 5(five) parts of C to I)arts of CDBC as Illcasured by volume.

Preferably, tlie inclusion rate is, l.5(one and a half) : l(one) parts of C to parts of CDBC, as measured by volume.

Product from Stage 3 is then milled and screened to standard specifications for a multipurpose compost, then bagged.

In the following example, the dairy waste was produced by an Irish cheese manufacturer during a 38 to 40 week season from the end of February to the beginning of November.

The bark comprises matured/aged/composed bark (with or without an inclusion of poultry manure or similar nitrogen-source material included as an aid to the maturing process) derived from the de-barking of coniferous species (spruce/larch) logs.

Dairy-Waste-Sludge Specification: Dry matter not below 19%.

N:P:K not below 5.0:2.5:0.5 (on a dry matter basis).

Chlorine levels not exceeding 0.2% (on a dry matter basis).

Heavy metal and fluorine levels not exceeding The Soil Association permitted maxima (where stated) for a manurial product (Section 3.503, Revision 5) and preferably not above the following: mg/kg (dry matter) Zinc 600 Copper 150 Nickel 100 Cadmium 3 Lead 280 Mercury 2 Chromium 280 Molybdenunl 4 Selenium 3 Arsenic 14 Fluorine 400 Test methods and analysis for heavy metals are as per the requirements of Directive 86/278/EEC.

Bark Specification: Minimal sawdust and white wood content.

Manganese levels not exceeding 0.02% (200 mg/l) of dry matter.

Material is matured/aged/composted for a minimuili of six weeks.

Particle size distribution (by volume): Not more tloan 15% < 0.4mm.

Nol niore than 2% > 25mm.

Specification for Bark and Dairy-Waste-Sludge Combination: # Maximum acceptable sand (particle size range 0.25 - 5mm) not more tloan 2% by weight.

Product free of: Gravel and stones (5mm and above).

MEtal objects and other extraneous material.

Petrochemical contamination, (oil, diesel, etc).

Putrefaction odour at or above levels deemed offensive by competent authority.

Vegetable Transplants Screening Trials Experimental Protocol: The system uses tle cellular Hassay 308 tray, which has a cell volume of approxiinalely 15 mL. The trays are evenly filled with the growing media, any excess being scraped off with a board.

Seeds are sown one per cell and lightly covered witli the medium. Seeded trays are placed on tile glassllousc bench (galvanized wire mesh lo encourage air pruning) and watered thoroughly to initiate germination.

Once the seeds have begun to emerge, they are assessed daily to determine the germination rate. A seedling is counted as having emerged when it first appears above tlie soil surface.

During the growing period, the trays are watered as required, and tlie trial is continued until the plants are deemed ready for transplanting. At this stage the plants are assessed for true leaf stage, by a rooting index (1 = least, 5 = greatest rooting) and fresh and dry weight (mean of 30 plants chosen al random leaving a perimeter gilard row).

The data (where appropriate) are slalislically analysed using eilher twoway analysis of variance (continuous data) or Friedmans F, test (discrete data). In either case, where tlie analysis slows a significant treatment effect, tests are carried out to isolate treatements which are significantly different, and results are presented garphically. Significant differences are shown both as a value where this is applicable, and as lower case letters where treatements with the same letter are not significantly different.

Example of the invention #1 - Co-composted Dairy-Waste and Bark. The nutrient source used in this trial was a compost based on dairy-waste ancl bark. The material used (ie following sieving - sec below) had a total nitrogen content of 2.57%, total phosphors content of 4.14% and a total potassium content of 0.69%.

Materials a,1d methods. The composted dairy waste/bark (hereafter CDB) was received straight from tile composting windrow, and was dark grey in appearance and granular in texture. The parlicle size distribution was such that the material required screeniilg (6 mm sieve) before use, which gave rise to two fractions (# 6 Inrn 100 aid # 6 mm) of approximately equal mass. The # 6 mm fraction was retained for use in trials.

Experimental formulations consisted of the CDB (20, 40 and 60% incorporation rales) mixed with pre-wetted coir, and a proprietary substance (Dickensons Module Coiiipost) was used as a control.

Formulations (including the control) were mixed (on a gravimetric basis) in a concrete mixer on tlie day of use, at which tiiiie samples were taken for analysis.

Chemical analysis. Fresh, moist substrate is extracted with deionised water at 20 C. pH is determined oii tile uiifiltered extract, EC, ammonium- and nitrate-nitrogen, orthophosphate, potassium, magnesium and calcium on tlie filtered extract.

Procedure. The sample is spread out on a large tray and is mixed well.

Any lumps are broken down, and the sample is pushed through a 6.0 mm sieve if non-homogeneous.

This material is used to fill, without compaxtion, a weighed cylinder, calibrated (and ctlt-off) to I L. The substrate is struck off level with the top of the cylinder, and the net weight of the sample is determined. This procedure is repeated five times and a mean sample density (g L-1) is calculated.

The weight of 1/15 L of llle substrate is calculated. This ailiount is transferred to an extraction jar, and 400 ml deionised water is added. The jar is sealed, and shaken for 1 hour at 200C.

Following shaking, the pH is determined on the unfiltred suspension, which is then filtered through a Whatman No 2 filter paper. Electrical conductivity of the extract is determined. and tile filtrate frozen for future analysis.

Ammonium-nitrogen, nitrate-nitrogen and orthophosphate are determined colorinietrically using flow injection analysis, potassium by atomic emission spectroscopy, and calcium and magnesium by atomic absorption spectroscopy.

Analyses are expressed as mg L-' of the fresh, moist, substrate.

Hassay 308 trays were half filled (ie 154 cells), and lettuce (lactuca sariva cv Debby) and cabbage (Brassica olerecea var capitata Spirit) were sown one seed per cell. Seeded trays were lightly covered, and transferred to a glasshouse maintained at a temperature of ~ 18 C during the day and ~ 15 C at night. Trays were watered (tap watre) as required, and biological control agents used as ilecessary.

Germination was assessed for five days following emergence, and the final assessment made seven weeks after tlie sowing date.

Results. The water-soluble analyses of the "raw" materials and trial formulations are presented iii Table 1. The CDB had a pH of 6.6 and an EC of 1259 yS, and very high levels of water-soluble nutrients, and lhis was in coiitrast to toe coir which had low levels of nutrients. The experiniental formulations had pH and EC levels relating to tile ratio of source materials, however this pattern was not enlirely consislent for the nutrient levels.This is a frequent observatioio with organic growing medium, and is most likely due to the selective extraction of particular nutrients during tlie extraction procedure.

Germination rates of the experimental treatments for both lettuce and cabbage (Tables 2 and 3 respectively) were high, although not quite as high as in tile control trealíllent. Similarly, total levels of germination were high, but still slighlly lower than tlie control. No level was so low as to be of cause for concern, and indeed these results suggest that a greater amount of the CDB could have been used without any major effect on germination rate.

The final assessinent results for lettuce and cabbage are shown in Figure 1. In tile experimental treatments (1, 2 and 3) there was a general pattern of an increase in bioniass as the amount of CDB increased in the formulation. This was particularly the case for lettuce (fresh or dry weight) and cabbage (fresh weight only). Of particular note was the performance of the experimeiital formulations compared to the control treatment, in that the latter only achieved growth in terms of fresh weight comparable to Treatinent I (20% CDB).

Although the CDB nutrient source reqtiired screening before use and had a high moisture content makillg il "heavy" to use, the results of these experiments clearly demonstrate the potential of the dairy waste as a component of a coniposted growing medium nutrient source. The high levels of nutrients in this waste are, following composting, clearly available to plants in quantity over tile growing period, but at the same time do not cause inhibition of seed germination.

Example 2 of the invention &num;2 - Co-con1posted Dairy-Waste, Bark and Coir. The nutrient source used in this trial was a colposl based on dairy waste, bark and coir. The material used load a total nitrogen coiilciil of 1.49%, total phosphorus content of 2.03% and a total potassium coiltciit of 0.48%.

Materials and methods. The composted dairy waste/bark/coir (hereafter CDBC) was received straight fiolli tlie composting windrow. It was processed by reducing the water content (by spreading the compost out on a plastic sheet in a polytunnel and leaving lor scvcral days), followed by shredding in a garden shredder to reduce tlie mean particle size. The shreadded compost was than thoroughly homogenised before use.

Experimental formulations consisted of the CDBC (25, 50 and 75% incorporation rates) mixed with pre-wetted coir, and a proprietary substrate (Dickensons Module Compost) was used as a control.

Formulations (including the conlrol) were mixed (on a gravimetrie basis) in a concrete mixer the day before use, at wliicli time samples were taken for analysis. Hassay 308 trays were half Filled (ie 154 cells), and lettuce (Lactuca sativa cv Debby) and cabbage (Brassica olerecea var capitata Spirit) were sown one seed per cell. Seeded trays were lightly covered, and transferred to a glasshouser maintained at a temperature of ~18 C during tlie day and 15 C al night. Trays were watered (tip water) as required, and biological control agents used as necessary.

Geriiiination was assessed for five days following emergence, and the final assessment made six weeks after the sowing date.

Results. The water-soluble analyses of the "raw" materials and the trial formulations are presenled in Table 4. Tllc CDBC had a pH of 7.0 and an EC of 1031 S, and high levels of nitrate (indicating compost maturity) and potassium, In contrast, the coir had very low levels of water-soluble nutrients with the exception of potassium, confirming its suitability as a substrate diluent. Tlie experimental formulation load pH and EC levels relaling lo tlie ratio of source materials However Illis pattern was not entirely consistent for the nutrient levels.This is a frequent observation with organic stibstrates, and is Most likely due to tlie selective extraction of particular nutrients during the extraction procedure.

Germination rates for botll letlice and cabbage (Tables 5 and 6 respectively) were high for all treatments. as were Llie total levels of germination. The slightly lower total germination levels achieved in the cabbage were most likely a characteristic of the seed batch. Of particular interest was the germination in Treatment 3, which despite having a high EC showed no effect in ternis of reducing gernlillation.

Figure 2 shows the final assessnient results for lettuce and cabbage.

These showed tloat fresh and dry weight in both lettuce and cabbage increased as the amount of CDBC in the substrate increased. Although a similar trend was observed for leaf number and rooting index, tlie differences were not statistically significant at the 95 % level. Compared to any other treatment, Treatment 3 (75% CDBC) had the highest biomass in both lettuce and cabbage, whether measured as fresh or dry weight.

Treatment 2 (50% CDBC) had a higher lettuce dry weight than the control medium, and a slightly lower cabbage dry weight although this was not statistically significant. In all cases Treatment 1 (25 % CDBC) showed the least biomass growth.

From these results, it is clear that the CDBC nutrient base of the invention is a high-performance lititrient source in organic growing media. The fact that no inhibitory effects oli geriiiina(ioio ill Treatment 3 were observed suggests that this nutrient base could be used safely for germinaling seeds at very high incorporation rates. At tlie same line, it is clear that the media (in comparison with tlie control growing medium) has a very high nutrient supplying capacity, making it suitable for a wide range of growing media uses.

The first growing Inedia of the invention tested - co-composted dairy waste and bark - had an exceptional nutrient supplying capacity, producing lettuce growth coinparable to tlie control formulation at a 20% inclusion rate. However this coilipost, whilsl being an excellent nutrient source, was difficult to handle and mix.

These problems were absent from tlie second embodiment of the invention, formed by co-coiolposting dairy waste sludge with bark and coir-derived material. This nutrient base exhibited improved physical properties, and an exceptionally good (albeit slightly reduced compared to the co-composted dairy waste sludge plus bark (CDB) nutrient base) nutrient supplying capacily. In addition, although this nutrient base readily supplies nutrients for plant growth, it does not (at the 75% inclusion rate in a growing medium) have inllibitory effects on seed (lettuce or cabbage) germination.

Table 1: &num;1 - Media Analyses

Treatment pH EC NH4-N NO3-N PO4-P K ( s) (mg L-1) (mg L-1) (mg L-1) (mg L-1) A CDB (# 6 mm) 6.6 1259 560 187 118 600 B Coir 5.6 183 < 0.01 < 0.01 5 132 1 20% CDB:80% Coir 6.6 496 129 51 212 360 2 40% CDB:60% Coir 6.7 738 223 170 163 456 3 60% CDB:40% Coir 6.7 1023 449 142 208 552 4 Dickensons Module Compost 6.3 724 < 0.01 260 4 468 Table 2: &num;1 - Lettuce Germination Assessment

Treatment Percentage Germination (days after emergence and total) 1 2 3 4 5 Total 1 20% CDB:80% Coir 92 93 95 95 95 95 2 40% CDB:60% Coir 88 91 92 92 92 93 3 60% CDB:40% Coir 89 94 95 95 95 95 4 Dickensons Module Compost 79 97 99 99 99 99 Table 3: &num;1 - Cabbage Germination Assessment

Treatment Percentage Germination (days after emergence and total) 1 2 3 4 5 Total 1 20% CDB:80% Coir 72 84 87 88 89 89 2 40% CDB:60% Coir 50 82 87 88 88 88 3 60% CDB:40% Coir 35 70 80 81 82 84 4 Dickensons Module Compost 66 89 91 92 93 94 Table 4: &num;2 - Media Analyses

Treatment pH EC NH4-N NO3-N PO4-P K ( s) (mg L-1) (mg L-1) (mg L-1) (mg L-1) A CDBC 7.0 1031 9 225 47 900 B Coir 6.6 160 < 0.01 1 7 156 1 25% CDBC:75% Coir 7.2 419 < 0,01 54 104 468 2 50% CDBC:50% Coir 7.1 717 0.3 107 51 540 3 75% CDBC:25% Coir 7.0 825 0.8 102 38 480 4 Dickensons Module Compost 6.9 794 22 135 7 360 Table 5: &num;2 - Lettuce Germination Assessment

Treatment Percentage Germination (days after emergence and total) 1 2 3 4 5 Total 1 25% CDBC:75% Coir 54 91 94 95 96 97 2 50% CDBC:50% Coir 44 97 98 98 98 99 3 75% CDBC:25% Coir 14 87 94 95 96 99 4 Dickensons Module Compost 20 88 94 95 96 97 Table 6: &num;2 - Cabbage Germination Assessment

Treatment Percentage Germination (days after emergence and total) 1 2 3 4 5 Total 1 25% CDBC:75% Coir 39 81 84 88 88 89 2 50% CDBC:50% Coir 51 86 87 89 89 90 2 75% CDBC:25% Coir 46 86 89 91 91 92 4 Dickensons Module Compost 28 85 89 90 90 92

Claims

CLAIMS l. Growing medium comprising a nutrient base derived from food processing effluent, mixed with a matrix material.
2. Growing medium as claimed in claim 1, wherein the food processing effluent is dairy waste, meat waste, vegetable processing waste, waste from an industrial fermentation process, or a mixture of any thereof.
3. Growing medium as claimed in claim l or claim 2, wherein the nutrient base comprises dairy waste and bark.
4. Growing medium as claimed in claim 3, wherein the nutrient base further comprises coir-derived material.
5. Growing medium as claimed in any preceding claim, wherein the effluent is sludge comprising de-watered effluent from cheese processing.
6. Growing medium as claimed in any preceding claim, wherein the sludge has a solids content of more than 10%.
7. Growth medium as claimed in any preceding claim wherein the components of the nutrient base are co-composted.
8. Growing mediuiii as claimed in any preceding claim wherein tl1e matrix material comprises bark and/or coir derived malerial.
9. A method of making a nutrient base for a growilig medium comprising mixing Food processing waste and a matrix material.
10. A method as claimed in claim 9 wherein tile coniponents are co-compostcd.
II. A melllod as claimed in claim 10 wherein tlie co-composting process is aerobic.
12. A method as claimed in claims 10 or claim II wherein tlie composting process is carried out until the temperature of the mixture does not exceed 43 C within 72 hours of being disturbed.
13. A method of producing a growing medium comprising mixing a nutrient base prepared in accordance with any of claims 9 to 12 with at least one matrix material.
14. A method as claimed in claim 13, wherein the nutrient base is mixed with coir in an amount of at least 20% by volume of the total growing mediwn mixture.
15. Growth medium comprising a mixture of a food processing waste nutrient base and a matrix material substantially as described herein with reference to one or more of tile accompanying examples and figures.
16. A method of making a food processing waste nutrient base or a growing medium substantially as described herein with reference to one or more of the accompanying examples aiid figures.