What is Vermicomposting?



Vermicompost (also called worm compost, vermicast, worm castings, worm humus or worm manure) is the end-product of the breakdown of organic matter by some species of earthworm. Vermicompost is a nutrient-rich, natural fertilizer and soil conditioner. The process of producing vermicompost is called vermicomposting .  The earthworm species (or composting worms) most often used are Brandling Worms (Eisenia foetida) or Red Wigglers (Lumbricus rubellus). These species are only rarely found in soil and are adapted to the special conditions in rotting vegetation, compost and manure piles. Composting worms are available from mail-order suppliers, or from angling shops where they are sold as bait. Small-scale vermicomposting is well suited to turn kitchen waste into high-quality soil, where space is limited.  In addition to worms, a healthy vermicomposting system hosts many other organisms such as insects, mold, and bacteria. Though these all play a role in the composting process, the earthworm is the major catalyst for the composting process. 


  Most small bins used in the vermicompost process can be grouped into three categories: 


 Non-continuous – an undivided container. A layer of bedding materials is placed in the bin, lining the bottom. Worms are added and organic matter for composting is added in a layer above the bedding. Another layer is added on top of the organic matter and the worms will start to compost the organic matter and bedding. This type of bin is often used because it is small and easy to build. But it is relatively difficult to harvest because all the materials and worms must be emptied out when harvesting. 


• Continuous vertical flow – a series of trays stacked vertically. The bottom-most tray is filled first, in a similar fashion to any other bin, but is not harvested when it is full. Instead, a thick layer of bedding is added on top and the tray above is used for adding organic material. Worms finish composting the bottom tray and then migrate to the one above. When a sufficient number of worms have migrated, the bottom tray can be collected and should be relatively free of worms. These bins provide an easier method of harvesting.


  • Continuous horizontal flow – a series of trays lined horizontally. This method too relies on the earthworms migrating towards a food source in order to ease the process of harvesting. The bin is usually constructed to be similar to a non-continuous bin but longer horizontally. It is divided in half, usually by a large gauge screen of chicken wire. One half is used until it becomes full, then the other half is filled with bedding and organic matter. In time, the worms migrate to the side with the food and the compost can be collected. These bins are larger than a non-continuous system but still small enough to be used indoors, with the added bonus of being easier to harvest.