Vermicomposting is a method of converting wastes into compost through the use of earthworms. Depending upon the number of earthworms used, the time required for composting will also vary considerably. Large quantities of waste can be composted by this method. About 4–5 kg of wastes can be composted by 1000 worms (approximately 1 kg) in a day. The commonly used earthworms are Eudrillus sp.,Perionyx sp., Eiseniasp, etc.
For setting up a compost pit, dig a pit of size 2 m x 1 m x 0.45m. The length can be adjusted according to the requirement. Fill the basal 0.15 m with broken bricks or pebbles. Put a layer of coarse sand to a thickness of 0.05 m over this to ensure proper drainage. This is followed by a 0.15 m moist layer of loamy soil. Into this soil, inoculate about 3000 locally collected earthworms. Scatter small lumps of cattle dung (fresh or dry) over the soil. The dung serves as food for the worms in their early stages. Cover this with dried leaves or hay up to 0.05 m. Sprinkle water and keep the entire setup moist. Keep the unit covered with coconut fronds.
Spread organic refuse from the thirty-first day on the bed after removing the fronds. The spread should not exceed 0.05 m in thickness for each application. This can be done twice a week. After a few applications, turn over the refuse without disturbing the bed. When enough refuse has been added into the unit, keep it moist and 45 days later the compost is ready for harvest.
The base of the tank should have a slight slope directed towards two drainage holes. Composting can be done in pits, concrete tanks, well rings, wooden or plastic crates appropriate for a given situation. In places where worm predators like rats, lizards, pigs are a major problem, the tanks should be covered with wire mesh to protect the worms.