Worms live in the top layer of the soil. They are small creatures, often unnoticed and yet they are very valuable to farmers. They eat plant and animal leftovers, turning them into useful nutrients for plants. With their burrows they allow more air into the soil and improve drainage. Soils with plenty of worms will be fertile
The process of using earthworms to turn organic matter into compost is called vermi-composting.
They can turn household and garden waste into a very high quality soil conditioner and plant fertiliser. This improves the soil and increases small-scale vegetable production. Vermi-compost has no smell, is pleasant to handle and can be added directly to plants, used in seedbeds or placed in the bottom of seed drills. It can be produced by growing worms in special containers known as bins.
Making a worm bin
The worm bin may be made of wood, concrete, wire covered with plastic sheeting, metal, plastic or earthenware. It should be about 1.5m square and about 30–40cm deep, as composting worms tend to feed upwards, nibbling from material just below the surface. The larger the surface area, the more opportunity for worms to feed. The bin should either have no base or, if metal or plastic containers are used, a few drainage holes should be added. A 200 litre oil drum split lengthways (and washed carefully) makes two good containers. Fill the worm bin just as you would for making compost – layers of chopped vegetable and plant waste, and layers of manure and soil in between. Water the compost and cover it with a piece of black plastic, cardboard or bamboo matting. Always keep it damp and covered as worms will only grow in moist, dark conditions. After 1–2 weeks (when the initial heat from the compost has cooled) make holes and add either worms or eggs. There are over 4,000 species of worms, and only a few (small and bright red) are specialised for vermicomposting.
It is worth contacting the local agricultural extension or advisory services to see if you can obtain recommended species (such as Eudrilus euginea and Eisenia foetida). You will need about 50 to 100 worms to begin each composting box. If you cannot find any suppliers of composting worms, try using worms used for fishing bait or ordinary garden worms.
Composting worms will eat all types of kitchen vegetable waste. Grass and weeds should be allowed to dry out a bit to prevent the compost heating up too much. The waste can be added around the edges of the bin, using a different place each day in turn. It can be dug in a little to prevent flies or just left on the surface. After 2–3 months the vegetable waste will have turned into fine, very fertile compost and the worms will have multiplied rapidly. To harvest the vermicompost, push it to one side and stop watering it. Add old manure to the other side and keep it moist. The worms will move into the manure so you can harvest the vermi-compost. Then continue adding vegetable waste to the bin as before to produce more compost.
In business with the worm
During the 1980s Cuba had to find alternatives to imports of inorganic fertilisers. Cuba’s vermi-composting programme began in 1986 with two small boxes of red worms. Less than ten years later there were 172 vermi-composting centres in Cuba, producing over 99,000 tons of vermi-compost each year. One farmer in Ecuador, Enzo Bollo, has made the production of compost from worms into a huge business employing 14 fulltime workers and producing 20,000 sacks (33kg each) of valuable compost each year which is sold commercially.
Information provided by Sam Ross and CEDEPO, who have produced a cartoon booklet on worm farming. Their address is CEDEPO, CC 109, (1878), Quilmes, Provincia Buenos Aires, Argentina. Tel/Fax: (01)26 28 12
E-mail: [email protected] or [email protected].
Suppliers of worms
Hennie Eksteen, at Affmech, PO Box 300, Cato Ridge 3680, South Africa Meyer, at 18 Smit Street, Potchestrom, South Africa