Pusa vermicomposting

Photo: Jitendra Raj Bajracharya/ICIMOD.

Vermicomposting, or worm composting is a simple technology for converting biodegradable waste into organic manure with the help of earthworms (the red worm Eisenia foetida) with no pile turning, no smell, and fast production of compost. The earthworms are bred in a mix of cow dung, soil, and agricultural residues or pre-decomposed leaf-litter. The whole mass is converted into casts or vermicompost, which can be used on all types of plants in vegetable beds, landscaping areas, or lawns.

A 3m long, 1.25m wide, and 1m high pit is constructed with bricks on a moist and/or shaded site. If brick is not available, box or bamboo bin can also be used. To facilitate drainage digging into the soil, the base of the pit is covered with an 8 cm thick layer of sand. This is covered with a 15 cm thick layer of dry cow dung crushed into small pieces, followed by a layer of pre-decomposed degradable dry biomass and another thick layer of crushed dry cow dung. Finally the heap is covered with a thin layer of soil and the worms are poured on top.

A thatched roof should be built over the pit to maintain 40-50% moisture and 20-30°C temperature. Regular watering is needed to maintain the optimum moisture level. After 5-6 weeks, the top layer is removed and piled in one corner of the pit. After a few days, the newly exposed earthworms have burrowed down and the next top layer can be harvested. About 600 to 1000 worms can convert 45 kg of wet biomass in a week yielding about 25 kg of vermicompost. The earthworms are removed when all the compost has been taken out, and can be stored in moist paddy straw or a jute bag for later use. Vermicompost can be applied to any crop at any stage.