What’s the difference between compost worms & earth worms?

Earth worms are found usually in soil. As their tunnels are vertical they require considerable depth of soil. They live well underground and come to the surface to grab food and retreat down their tunnel. Most worm growers beds lack the depth that native worms prefer. Their metabolism and reproductive rates do not make them overly conducive for commercial worm growers to farm. They do play a vital role in the web of life in our soils and are an essential part of any healthy soil environment.

This category is used for worms that devour compost, either manures or food scraps generally. Compost worms have a much higher metabolism and reproductive rate than earth worms. This means they will eat more and so convert more organic matter down to castings.  They prefer to move horizontally in the search for organic matter and most of the population will be found in the top 5-10 cms of their bedding. They tend to go deeper if extremes of temperature force them to escape either the heat or the cold. Most of their life is spent crawling around the top few centimetres devouring organic matter and helping, along with abundant bacterial life, to  turn  the matter in a nutrient (which is available to plants) rich, microbe rich worm castings.

All the commercial worm farmers I have come across grow composting worms. There are 5 commonly grown species in Australia. In laymens terms they are reds, tigers and blues. Scientific classifications are Lumbricus rubellus (red), Eisenia fetida (tiger) and Perionyx excavates blue are the smallest but all are very good at converting organic matter to worm castings. The African night crawler ( Eudrilus eugeniae)  and European nightcrawler (Eisenia Hortensis) are much larger composting worms which makes them a popular choice for fishermen as well as gardeners wishing to turn compost into castings.

It is becoming popular to introduce compost worms into garden beds. For this to succeed remember that compost worms need organic matter, either manures, composted materials or food scraps so have plenty of these incorporated into the bedding and your worms will do well as will your plants.