Epigeic worms are surface dwellers and feed only on decaying organic material, not soil. They are not powerful burrowers, instead preferring to live in loose organic litter (like fallen leaves) or very loose topsoil rich in organic matter. They will not survive in most garden soils unless there is a good layer of organic matter on top. They are small and usually darkly colored, and reproduce at a high rate in ideal conditions. Because epigeic worms live on the very surface of soil, they are better able to withstand temperature and moisture fluctuations than other worms. Epigeic worms create castings that are many times higher in nutrients than the material they originally consumed, and are a vital part of the soil food web.
For your vermicomposter, we recommend using the epigeic worm Eisenia fetida, or red wiggler, also known as manure worms, trout worms, trigger worms, or compost worms. Small and reddish-brown, they are perfect for worm composting. This is because their natural habitat can be duplicated in a worm composting bin, they reproduce quickly and are happy to live in high-population density situations, and they are able to handle fluctuating temperature and environmental conditions. They are also voracious eaters, consuming up to half of their body weight in decaying organic matter per day. Red wiggler worms are tolerant of handling by humans and have a very wide range of potential foods. Amy Stewart, in her wonderful book The Earth Moved: On the Remarkable Achievements of Earthworms, recommends the red wiggler for composting at home:
Eisenia fetida is the perfect worm for domestication. It thrives in waste. A pile of garbage is its home. The fact that we can also use it to bait a hook or feed a chicken makes it all the more suited for life alongside humans. In fact, unlike the domestication of cats or dogs, the domestication of the red wiggler requires no changes on the part of the worm. It is already fully equipped to do the job we’re asking it to do, which seems like an extraordinary coincidence. Perhaps Eisenia fetida, by following the spread of humans around the globe over the last few million years, and moving into our paddocks and our garbage dumps, has already adapted itself to us. Maybe it has been domesticated all along, and it has just been waiting for us to notice (163).
There are several other epigeic worms that are good for composting. Lumbricus rubellus, or redworm, is very similar to the red wiggler in size, feeding and habitat preferences, and suitability for composting. The Eisenia hortsenis, or European nightcrawler, is also known as the Belgian, Super Red, Carolina Crawler, Giant Redworm, ENC and Blue Worm. These are larger than Eisenia fetida and live deeper in a worm composting bin. They reproduce more slowly than the Eisenia fetida. Another suitable worm is the Eudrilus eugeniae, or African nightcrawler, which is even larger than the European nightcrawler and is good for fishing. It cannot handle extreme cold, disruption of its environment, or being touched very much. The Perionyx excavates, also known as Malaysian Blue Worm or Indian Blue Worm, is thinner and faster than the Eisenia fetida and has an iridescent blue sheen. It is a tropical species not suitable for conditions in most of North America (Hawaii excepted). In hot, tropical weather, Perionyx excavates has been known to invade worm composting systems and drive other species of worms out.
For sources of composting worms, visit www.FindWorms.com.