What is Vermicompost ?

Vermicompost is a product obtained after decay of various species of worms usually red wigglers, white worms and earthworms to create a heterogenous mixture of decomposing vegetable or fruit waste, bedding material and vermicast. Vermicast also known as worm castings, worm humus or worm manures is the product after the breakdown of organic matter by species of earthworms containing water soluble nutrients. Vermicompost is an excellent organic fertilizer which contains nutrients and is a good soil conditioner. The process of producing vermicompost is called vermicomposting. The most commonly used earthworm species or composting worms are red wigglers. Europen nightcrawlers, blue worms and Belgium crawlers may also be used. These all species are commonly found in organic rich soils throughout Europe, North America and live in rotting vegetables, compost and manure piles. They may be invasive species in some areas and feed on decomposing plant matter in soil. Large scale vermicomposting is practiced in Italy, Japan, the Philippines and USA. The vermicompost can be used for farming and landscaping. There are two main methods on large scale vermiculture. Some systems use windrows which consist of bedding material for the earthworms to live in and act as a large bin. Organic matter is added to it although the windrows have no physical barrier to prevent worms from escaping. Often windrows are used as a concrete surface to prevent predators to gain access to warm temperature. 

In the second type, vermicompost is the raised bed or the flow of system where the worms are fed across the top of the bed because red worms are surface dwellers. They continue to move all the time towards new food source. They flow through system, eliminate the need to separate worms from casting before packing. Vermicompost t home has a large variety of bins commercially available. The variety of containers can be used. They may be made of plastic, wood, styrofoam or metals. The design of the small bin usually depends on where an individual wishes to store the bin and how they wish to feed the worms. 

Metal containers are good conductor of heat and are prone to rusting and may release heavy metals into the vermicompost.

Small scale vermicompost is well suited to turn kitchen waste into high quality soi amendment. Worms can decompose organic matter without the additional human physical effort but bin composting requires decomposing effort.

Climate and Temperature

The most worms used in composting system, feed most rapidly at temperature of 50-55°C. If worm is kept outside it should be kept in sheltered position away from direct sunlight and insulated against frost. Temperature of the large scale bin system should be controlled as the feed stalks used can cause heating up of the worm bins as they decompose and kill the worms. Such systems usually use kitchen or garden waste using earthworms  and other microorganisms, digest organic waste such as:

  • All fruits and vegetables including citrus and other high acid fruits
  • Vegetables and fruit feeds and coffee grounds and filters, tea bags and other grains such as bread, crackers and cereal including moldy and stale eggs shell, leaves and grass clippings, small scale pesticides.

In a large scale or commercial system, vermicompost rely on large quality of 

  • Dairy cow or pig manure
  • Sewage sludge
  • Agricultural waste
  • Food processing and grocery waste
  • Cafeteria waste
  • Grass clippings and wood chips

Harvesting

Vermicompost is ready for harvest when it contains few to lower scraps of eaten food or bedding. There are several methods

  • Hand sorting
  • Let the worms do sorting
  • Alternate containers or divide and dump

Benefits of Vermicomposting

Benefits with reference to Soil

  • It improves the physical structure of soil.
  • Enrich soil with microorganisms.
  • Microbial activity in worm casting is 10-20 times higher than in the soil and organic matter that the worms ingest.
  • Attract deep burrowing earthworms already present in soil.
  • Improves water holding capacity of soil.

Benefits with reference to Plant Growth

  • Enhances germination, plant growth and crop yield.
  • Improves root growth and structure.
  • Enriches soil with microorganisms by adding plant hormones such as auxins and gibberellic acid.

Benefits with reference to Economy

  • Biowaste conversion reduces waste flow to landfills.
  • As the biowastes are eliminated from the waste streams, it reduces contamination of other recyclables collected in a single bin.
  • Creates low skill jobs in local level.

Benefits with reference to Environment

  • Help to close metabolic gap through recycling waste on-site.
  • On large scale systems temperature control and mechanized harvesting is considered however other equipment is relatively simple and does not wear out quickly.
  • Production reduces greenhouse gas emissions such as methane, nitric oxide, etc.