About worm farms
Worms can be kept in any container, as long as it is well drained, aerated and covered. Old fridges provide good insulation from the heat and many people favour farms made from plastic or polystyrene vegetable boxes.
To use a vegetable box make holes in the bottom of one box to let liquid drain. Place the box with the holes over another box without holes and make a tap in the bottom box to let the liquid out. Place an upturned ice-cream container or a brick in the bottom box to help any worms that fall through the holes to climb up into the upper box.
Commercially available ‘worm factories’ consist of two trays with perforated bases, which fit onto a collector tray with legs. The top tray holds the worms and bedding, the second tray holds the previous cycle’s worm-casts and the bottom collector tray collects the leachate liquid.
Worm-casts are the by-products of the worms’ activities. They are nutrient rich excrement which can be used to improve soils, potting mixes and compost. Good round, crumbly castings may take several months to produce, but because of their unique biological and organic composition they are magnificent soil conditioners. Leachate is the liquid produced by the worms and the natural decomposition of food scraps and other organic materials. It too is nutrient rich, full of microbes and beneficial bacteria and can be used as a powerful fertiliser.
Earthworms most suitable for garden rearing are introduced species such as the common tiger worm, Eisenia fetida, or the red worm, Lumbricus rubellus. These worms are more gregarious than native worms, tolerate disturbances better, and generally breed to higher populations. They usually live from 2–4 years but have been known to survive for over 15 years.
Worms are hermaphrodites, possessing both male and female reproductive organs, but use a partner to breed. Eggs are laid within capsules in the soil and will hatch in about three weeks. These worms mature 60 to 90 days later and can then lay an egg capsule about once a week for several years.