Vermicompost (vermi-compost) is the product of the decomposition process using various species of worms, usually red wigglers, white worms, and other earthworms, to create a mixture of decomposing vegetable or food waste, bedding materials, and vermicast. This process is called vermicomposting, 

Suitable worm species

All worms make compost but some species are not suitable for this purpose. Vermicompost worms are generally epigean. Species most often used for composting include:

• Eisenia fetida (Europe), the red wiggler or tiger worm. Closely related to Eisenia andrei, which is also usable.

• Eisenia hortensis (Europe), European nightcrawlers, prefers high C:N material.

• Eudrilus eugeniae (West Africa), African Nightcrawlers. Useful in the tropics.

• Perionyx excavatus (South and East Asia), blueworms. May be used in the tropics and subtropics.

• Lampito mauritii (Southern Asia), used locally.

 

Properties

Vermicompost has been shown to be richer in many nutrients than compost produced by other composting methods.It has also outperformed a commercial plant medium with nutrients added, but levels of magnesium required adjustment, as did pH.

However, in one study it has been found that homemade backyard vermicompost was lower in microbial biomass, soil microbial activity, and yield of a species of ryegrass than municipal compost.

It is rich in microbial life which converts nutrients already present in the soil into plant-available forms.

Unlike other compost, worm castings also contain worm mucus which helps prevent nutrients from washing away with the first watering and holds moisture better than plain soil.

Increases in the total nitrogen content in vermicompost, an increase in available nitrogen and phosphorus, a decrease in potassium, as well as the increased removal of heavy metals from sludge and soil have been reported.The reduction in the bioavailability of heavy metals has been observed in a number of studies

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Benefits

Soil

• Improves soil aeration

• Enriches soil with micro-organisms (adding enzymes such as phosphatase and cellulase)

• Microbial activity in worm castings is 10 to 20 times higher than in the soil and organic matter that the worm ingests

• Attracts deep-burrowing earthworms already present in the soil

• Improves water holding capacity

Plant growth

• Enhances germination, plant growth, and crop yield

• It helps in root and plant growth

• Enriches soil organisms (adding plant hormones such as auxins and gibberellic acid)

Economic

• Biowastes conversion reduces waste flow to landfills

• Elimination of biowastes from the waste stream reduces contamination of other recyclables collected in a single bin (a common problem in communities practicing single-stream recycling)

• Creates low-skill jobs at local level

• Low capital investment and relatively simple technologies make vermicomposting practical for less-developed agricultural regions

Environmental

• Helps to close the "metabolic gap" through recycling waste on-site

• Large systems often use temperature control and mechanized harvesting, however other equipment is relatively simple and does not wear out quickly

• Production reduces greenhouse gas emissions such as methane and nitric oxide (produced in landfills or incinerators when not composted).