Vermicomposting

Building a working vermicomposting unit starts with site and structure: an upland or elevated bed avoids waterlogging, and a typical cement pit (roughly 3m x 2m x 1m) is built over the ground with brick walls and a drainage outlet for excess water, kept shaded since direct sunlight harms the worms. The bed is layered from the bottom up — first about 5 cm of gravel, then roughly 3.5 cm of coarse sand to aid drainage — before the loading layer goes on top. If native-soil earthworms are used, a further 15 cm layer of local loamy soil is added on top of the sand for the worms to settle into; exotic species such as Eisenia fetida and Eudrilus eugeniae skip this soil layer entirely. The unit is then loaded with digested biomass or cooled animal dung, the chosen earthworm species is introduced on top, and the whole bed is covered with jute bags, cardboard or broad leaves. Moisture management is the single most important ongoing task, since both too little and too much water harm the worms. As the worms process the biomass, they release visible castings on the surface, which signal that harvesting can begin; a full batch can take several days to finish composting depending on how much biomass was loaded, and it is later collected by heaping the compost into cones under sunlight so the worms move down and cluster at the base, from where they can be handpicked and reused. A separat …