GB2387841A

GB2387841A - Growing medium free from peat and animal products

Info

Publication number: GB2387841A
Application number: GB0209409A
Authority: GB
Inventors: Munoo Prasad
Original assignee: Bord na Mona PLC
Current assignee: Bord na Mona PLC
Priority date: 2002-04-25
Filing date: 2002-04-25
Publication date: 2003-10-29
Also published as: GB0209409D0

Abstract

A growing medium comprises a compost of spruce bark 10 and a nitrogen containing material 16, and limestone 22. Preferably the nitrogen containing material is a plant-based nitrogen source, such as soya bean product, castor cake, or neem cake. The growing medium is produced by hammer milling the spruce bark down to chippings of 10 mm or less, passing them through a screen 12, mixing them with soya bean product 16, composting the mixture and subsequently adding limestone 22 to the compost. Copper sulphate 24 and ferrous sulphate may also be added after the composting stage. Preferably the mixture of bark and soya bean meal contains 600-800g of nitrogen per 1m<3> of bark.

Description

238784 1

Growing Medium This invention relates to a growing medium for use, for example, in the cultivation of young plants or in growing bags for larger plants.

The growing media commonly used in such applications are often peat s based, but there is an increasing move away from the use of peat in such applications. Further, known products often include anneal products, for example bone meal, or manure or other animal waste products and so may not be suitable for use by certain groups of growers, for example certain organic farmers or vegans.

10 It is an object of the invention to provide a growing medium suitable for use in such applications, and to provide a method of producing such a growing medium. According to the present invention there is provided a growing medium comprising a mixture of limestone and a compost of spruce bark, and a nitrogen 15 containing material.

The nitrogen containing material is conveniently a soya bean product.

The compost may furler include other materials, for example other bark materials. Preferably the mixture further includes a ferrous sulphate material and 20 copper sulphate.

The invention also relates to a method of producing a growing medium comprising composting a mixture of spruce bark and a soya bean product, and subsequently adding limestone to the compost.

The spruce bark used in the formation of the compost is conveniently of 5 10mm. The process may include a hammer milling operation to break the spruce bark down to this size. A screening operation may be performed to ensure that the bark used meets this requirement.

The soya bean product is conveniently soya bean meal and is preferably mixed with the spruce bark at a rate of 600-800g, preferably 700g, nitrogen per 10 lm3 of bark. Other suitable nitrogen confining material include castor cake and neem cake.

The limestone is preferably dolomitic limestone and is conveniently added to the compost at a rate of 2-4kg, preferably 3kg per lm3 of compost.

Preferably, small quantities of a ferrous sulphate and copper sulphate are 15 added to the growing medium.

The invention will now be described in greater detail, by way of example only, with reference to the accompanying diagram (Figure 1) which is illustrative of the method of producing the growing medium.

A quantity of spruce bark 10 is screened by a screening device 12 to 20 remove large bark chippings therefrom leaving chippings having at least one

dimension less than lOmm. These bark chippings are mixed by a mixer 14 with soya bean meal 16 at a rate of approximately 700g of Nitrogen to lm3 of bark.

The particle size of the bark is selected to assist in aeration and in retaining water. If the particle size is too small, poor aeration can occur, and as a result 5 the composting process (described below) may be impeded or even stopped. If the particle size is too high, the material may dry out and heat generated during composting may not be retained.

The mixture is arranged in windrows of maximum height approximately 2m and of length approximately loom (denoted by numeral 18 in Figure 1.

10 Although windrows of other dimensions could be used, if the windrows become too tall then insufficient aeration may occur within the windrow, and the lack of; oxygen caused thereby may impede composting. The mixture is then allowed to de-compose to form compost. This typically takes around ten to fourteen weeks. i During this period, the mixture is turned regularly, preferably at least on a 15 weekly basis assisting in aeration. The composting process is monitored by measuring the acidity, temperature, nitrate nitrogen and carbon dioxide emissions from the windrows using conventional techniques. Towards the end of the I composting process, the ratio of carbon to nitrogen in the material is also measured. 20 Whilst the composting process is occurring, should any of the monitored

parameters move out of acceptable ranges, then appropriate remedial action can be taken. By way of example, if She carbon dioxide level is around 20%, then this maybe indicative of poor aeration. In order to improve aeration dhe windrows may be turned more frequency, or air may be blown through The s windrows. Likewise7 high EC and an increase in acidity may be indicative of anaerobic conditions. Again more frequent fuming or the blowing of air through the windrows to introduce more oxygen thereto may improve comporting.

Once it is has been determined from the measured parameters that the composting process has been completed the composted mixture is mixed by a 10 mixer 20 with dolomitic limestone 22 et a rate of approximately 3kg of limestone to lm3 compost and small quantities of copper sulphate 24 end a ferrous sulphate material 26 are also added.

One parameter used to determine when to terminate composting is the nitrate nitrogen level. When this parameter exceeds 80mg/1, plants grown in the 15 growing medium should be able to grow for at least three weeks without the addition of liquid feed.

The addition of the dolomitic limestone serves to optimise the acidity of the final product. It also provides calcium and magnesium. The soya material is added to optimise composting. The rate at which the soya material is added 20 (say 10kg/m3) is preferably sufficient to ensure that sufficient levels of residual

s nitrogen remain in the bark for plant growth. By way of example soya may be added at a rate of 3 -5kg/m3 higher than would otherwise be necessary to maintain the residual nitrogen level. The soya furler serves as a source of potassium, phosphorus and some other micronutrients.

5 As mentioned above, copper sulphate and ferrous sulphate are added in small quantities. Other inorganic micronutrient materials may also be added even where the product is to be used for organic gardening if it can be shown that a deficiency in micronutrient levels exists.

A mixture 28 so prepared can be used as a peat-free organic growing 10 medium for use in the cultivation of small plants or for use in, for example, growing bags used for larger plants. Trials have shown that the growing medium performs as well as a typical multi-purpose peat based growing medium.

Although described hereinbefore as an automated, or part automated, process, it will be appreciated that the process of the invention may be performed 5 completely by hand, if desired.

As mentioned hereinbefore, the growing medium does not include any animal products or arnmal waste products unlike a number of typical growing media. As a result, the growing medium is suitable for use in the cultivation of organic products including those suitable for vegans 20 Although a specific example has been described hereinbefore, it will be

appreciated that modifications may be made within the scope of tile invention.

For example the relative quantities of materials may be modified, or the spruce bark may be mixed with other types of bark. Further, although the method describes screening the bark a hammer milling operation could be used to break s down the bark into sufficiently small pieces.

Claims

1. A growing medium comprising a mixture of limestone and a compost of spruce bark, and a nitrogen containing material.

2. A growing medium according to Claim 1, wherein the compost further

includes other materials.

3. A growing medium according to Claim 2, wherein said other materials lo include other bark materials.

4. A growing medium according to any one of the preceding claims, wherein the mixture furler includes a ferrous sulphate material and copper sulphate.

15

5. A growing medium according to any one ofthe preceding claims, wherein the nitrogen containing material comprises at least one of a soya bean product, castor cake, Deem cake and another plant-based nitrogen source.

6. A growing medium substantially as hereinbefore described.

7. A method of producing a growing medium comprising composting a mixture of spruce bark and a nitrogen containing material, and subsequently adding limestone to the compost.

5

8. A method according to Claim 7, wherein the spruce bark used in the formation of the compost is of lOmm or less in at least one dimension.

9. A method according to Claim 8, further including a hammer milling i operation to break the spruce bark down to chippings of lOmm or less.

10. A method according to Claim 8 or Claim 9, further including a screening operation.

11. A method according to any one of Claims 7 to 10, wherein the nitrogen 15 containing material comprises at least one of a soya bean product, castor cake, neem cake and another plant-based nitrogen source.

12. A method according to any one of Claim 11, wherein the soya bean product is soya bean meal.

20 b

13. A method according to any one of Claims 7 to 12, wherein the nitrogen containing material is mixed with the spruce bark at a rate of 600-800g nitrogen per lm3 of bark.

5

14. A method according to Claim 13, wherein the nitrogen containing materiel is mixed with the spruce bark at a rate of 700g nitrogen per lm3 of bark.

15. A method according to any one of Claims 7 to 14, wherein the limestone is dolomitic limestone.

16. A method according to Claim 15, wherein the limestone is added to the compost at a rate of 2-4kg per lm3 of compost.

17. A method according to Claim 16, wherein the limestone is added to the 15 compost at a rate of 3kg per lm3 of compost.

18. A method according to any one of Claims 7 to 17, wherein small quantities of a ferrous sulphate and copper sulphate are added to the growing medium.

19. A method of producing a growing medium substantially as hereinbefore described with reference to the accompanying drawing.