WORM CASTINGS AND COMPOST WORMS

1. Industry & Products

Worm castings are the dry friable soil like product which remains after compost worms have completely digested a quantity of compost. Castings are sold in bulk for orchard and market garden use, or in small consumer packs for home gardeners.

The vermicast as it is known is not and cannot be registered as a fertiliser, because the nutritional value will vary according to the composition of the compost passing through the worms. However vermicast has a positive fertiliser action through breaking down the chemicals in the plant material ingested and returning it in a form available to plants. A worm consumes its own weight in organic matter daily and large quantities of bacteria and enzymes passed with it contribute further in making chemicals held in soil available to plants.

The potential of worm castings as a mulch in vineyards has recently been demonstrated by CSIRO research and some of the larger fruit and vegetable growers in Sunraysia and Swan Hill have recently expressed interest in sourcing large quantities. Worm castings are also increasingly being sought by organic farmers as a key part of their fertiliser program, and there is strong anecdotal evidence of benefits in home gardens.

Worm castings have a high moisture holding capacity which is a valuable property if used in quantity or in conjunction with young, seedling or germinating plants and as part of potting mixes.

2. Physical Requirement

The production of worm castings in quantity requires a large supply of organic waste available to be composted.

Any animal or vegetable waste can be used, including all house hold, garden and vegetable waste, fruit and other orchard waste, wood chips, straw, shredded paper and animal manures. In the Mallee production of worm castings has potential in association with any intensive animal industry. Horse manure or a mixture of pig manure and straw is the ideal basis.

The other main ingredient is composting worms and a nucleus supply can be purchased from breeders. There are 3 breeds of composting worms commonly used and they are different to normal garden earth worms.

A worm farm to supply bulk castings will require one or more hectares of land and a small but regular water or waste water supply to keep active worm beds damp.

Tractor and equipment will be needed to form the windrows or worm beds and to handle and market the worm castings.

3. Production

A commercial bulk worm casting operation can be developed on a system of adjoining windrows of waste material, built and processed in a cyclical pattern.

The first windrow is encouraged to compost, the time depending on the material and the composting method. Composting breaks down the material including any residues of chemicals in animal excrement which may damage worms. Composting initially generates heat. Compost temperatures must be below 25'c before worms are introduced.

When the composting worms are introduced the windrow must be kept wet and covered with old bags, carpet or straw. An adjoining windrow is built and will be composted down by the time the worms have converted the original windrow to castings. The second windrow is a fresh source of food and the worms will transfer automatically. This is encouraged by cutting off the water on the original windrow, and watering the new one. The first windrow is then allowed to dry out before being broken up in some way to form a free running organic fertiliser or mulch called vermicast.

Small scale units can be developed to build up worm stocks or to supply castings for small intensive units like herb growing.

A very small unit is available for use in the home or in schools and is useful in learning the principles and for building up base stocks of worms.

4. Marketing

5. Financial Aspects

6. Organisations and Contacts

7. References