Vermicomposting refers to the cultivation of earthworms, and vermicompost is the excretion of those worms, which is extremely rich in humus. Voracious eaters, the worms consume cow dung, barnyard manure and virtually any organic material, converting it into vermicompost. A simple and effective means of creating nutrient-rich soil, vermicomposting can be done indoors and out.
Simple and inexpensive, the end result of vermicomposting is a supply of nutrient-rich fertilizer. The National Sustainable Agriculture Information Service notes that "worms eat many types of organic waste materials and convert them into castings. This material is highly valued as a soil amendment because it contains plant-available yet stable nutrients." Unlike traditional composting, there is less of a smell associated with vermicomposting, so maintaining an indoor bin is also an option.
An indoor vermicompost bin should consist of a large plastic bin with a lid on the top and a tray on the bottom. Drill several air holes around the bin to increase air circulation. Add shredded newspaper (no glossy magazines), dry leaves and several handfuls of sand and soil. Next, place around 500 worms on the top of the pile. The worms will crawl to the bottom. Begin feeding the worms by placing raw vegetables, coffee grounds, egg shells and other organic unprocessed table scraps in a different corner of the bin each week. Keep the materials moist by adding water frequently.
An outdoor vermicompost bin constructed of non-treated wood will allow for better ventilation as well as absorption of excess moisture. Keep the bin covered to provide a dark environment. Proper ventilation is important. For best results dig a trench 1 foot deep and place the bin inside, surrounding the side with soil. This should help insulate the bin and protect it through the winter. You cannot overfeed the worms, but they can only consume their weight in food daily. Overloading the bin with scraps can lead to a foul smell from food rot.
While there are generally two types of worms used in vermicomposting, red wigglers and European nightcralwers, the wigglers are favored for their hardiness and productivity. Whichever worm you choose, do not mix the species in the same bin. Purchase worms online or through mail-order gardening catalogs.
Expect your first harvest of quality compost in three to four months. Carefully remove the worm castings (vermicompost) and worms and place them in four large piles on a tarp under light (sunlight is fine). The worms will move to the center of the tarp. Gather up the worms and return them to the bin to start the vermicomposting process over again. Unlike other dung-related fertilizers, worm castings are pathogen-free and present no risk to the gardener.
Eco-friendly, vermicompost is biodegradable and 100 percent natural. The worm casings have no adverse effect on soil or plants and help with soil aeration. The high nutrient value of worm casing exceeds barnyard manure for all nutrients and reduces or eliminates the need for synthetic hormones or chemical-based fertilizers.