Description

Vermicasting, also called vermicomposting, is the processing of organic wastes through earthworms. It is a natural, odourless, aerobic process, much different from traditional composting. Earthworms ingest waste then excrete casts – dark, odourless, nutrient- and organically rich, soil mud granules that make an excellent soil conditioner. Earthworm casts are a ready-to-use fertilizer that can be used at a higher rate of application than compost, since nutrients are released at rates that growing plants prefer.

Vermicasting can be done on a small scale by homeowners with household organic wastes, on a large-scale by farmers with manure or by the food industry using organic wastes such as fruit and vegetable cull materials. Through proper design, vermicasting is a method of waste handling that:

• is clean, socially acceptable, with little to no odour
• requires no energy input for aeration
• reduces the mass of waste by 30%
• produces a valuable vermicast byproduct
• even generates worms as fishing bait

Important Facts About Vermicasting

• Turning organic wastes into casts takes 22–32 days, depending on density of waste and earthworm maturity (regular composting requires 30–40 days, followed by 3–4 months curing).
• Vermicast does not need curing, but fresh casts undergo 2 weeks of nitrification where ammonium transforms to nitrate, a form that plants can uptake.
• Use organic materials that meet the earthworm's feed preferences, including a material density of 350–650 g/L.
• Worms should not be crowded, so the ideal stocking density is 150 earthworms/L of wastes.
• Earthworms ingest about 75% of their body weight/day; a 0.2 g worm eats about 0.15 g/day.
• If you discover earthworms trying to escape any system, it is a good indication that something is wrong with their feed or environment
• Earthworms should be allowed about 1 week to migrate from finished vermicast to fresh waste.