Also known as brandling worms, tiger worms or manure worms, red wiggler worms (eisenia fetida) are among the most popular types of earthworms used for vermicomposting (organic waste composting.) Red wiggler worms subside on items commonly placed in compost bins, such as vegetable and fruit scraps, tea bags, pulverized egg shells, and coffee grinds. After digesting their food, red wiggler worms excrete “castings,” a natural fertilizer that is rich in potassium, nitrogen and phosphorous. These castings may then be used as mulch, plant potting soil supplement, or lawn conditioner. Red wiggler worms are also sometimes used as fishing bait.

Red wiggler worms can be found naturally in manure piles; however, the most common method of obtaining them for is to place an order online. Gardening mail-order suppliers and fishing shops often carry red wiggler worms. The amount of red wiggler worms required to effectively compost depends on the amount of food waste. As a general rule, one pound (0.45 kg) of waste materials per day requires two pounds (0.9 kg) of red wiggler worms. Under ideal conditions, red wiggler worms can eat their weight in organic material daily.

It is advised that food waste such as meats, dairy products, and grains be kept out of worm composting, as these are likely to putrefy and attract rodents and flies. If red wiggler worms are taken care of properly during vermicompost, they shouldn’t cause offensive odors. One way of preventing odors during worm composting is to always “bury” new food waste rather than dumping it on top of the compost pile. As well, the compost should be maintained so that the red wiggler worms are kept away from the castings they produce. Certain vermicompost bins on the market facilitate this separation.

Compared to certain brands of organic fertilizer and even animal manure, worm castings have been shown to cause the least damage to water supplies. Unlike the animals that produce manure used as fertilizer for food crops, worms are incapable of contracting and spreading diseases. In fact, a worm’s digestive track removes the pathogens that cause disease from the food they ingest.