May 17, 2014

1 - Vermicomposting is the process of using worms to reduce kitchen and garden organic waste materials to worm castings.

Yard and Garden May 17, 2014


What is vermicomposting? Is it a difficult thing to do?


Vermicomposting is the process of using worms to reduce kitchen and garden organic waste materials to worm castings. Worm castings are the waste produces excreted by worms and are an organic material high in nutrients. The worms used for vermicomposting are manure worms that are commonly found in manure piles and other piles of organic materials. Unlike earthworms, they will usually stay in an area of high organic matter and not move far away. Earthworms on the other hand are nomadic and will move around a lot. Do not try vermicomposting with the earthworms you will find in your garden or on sidewalks after a heavy rain. Fishing worms are the compost worms and provide an idea of how to use the worms produced during vermicomposting. You can go fishing! Traditional composting as opposed to vermicomposting is the reduction of organic materials to compost by several different organisms, but especially by bacteria and fungi.

Vermicomposting is easy and can more rapidly reduce organic material to castings than traditional composting, but you must be careful to protect the worms from overheating and freezing. Traditional composting will generate heat that kills disease organisms, but will also kill compost worms. Winter freezing may slow traditional composting, but will not stop the compost process or harm the composting organisms. Compost worms can die if they get too cold.

Many gardeners make vermicompost in bins that they often keep indoors. The bins are aerated with holes through the material from which they are made. Kitchen wastes, including some materials that are usually excluded from traditional compost such as macaroni and cheese can be composted by worms.

Outdoor vermicomposting is possible, especially in the summer. When vermicomposting outdoors, gardeners should place a sheet of black (or dark colored) plastic over the ground where vermicomposting will occur. This material will maintain moisture and exclude light which causes problems for compost worms. However, to reduce temperatures below the dark plastic sheets, the area covered by the plastic sheet can be covered by bags of dried leaves or other insulating material. This may even allow winter vermicomposting outside in warmer areas of New Mexico. Kitchen or garden wastes are placed under one corner of the dark plastic and some compost worms placed in the food material. As the worms multiply and grow larger, increasing large quantities of food may be placed adjacent to the previous material. Over time this will result on a zig-zag pattern under the plastic. After the whole area under the plastic has been filled, some of the worms may be harvested and moved to a new location. The castings may be harvested to use in the garden or turned into the soil where they were produced. This will result in an excellent bed for vegetables or flowers.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email:, office: 505-865-7340, ext. 113.


For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.

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