Worms and compost are a match made in heaven. Worms love the stuff of compost bins, happily consuming it and then leaving behind worm castings (a.k.a. vermicast, worm humus, or worm manure), which is excellent fertilizer. So, we are able to convert our organic waste into something of value, and in so doing we make a lot of worms happy. We’ve written a lot about worm composting before (check out this article on the general topic of using worms in your compost, and here is another about a specific way to compost using worm farms), so we are certainly no strangers to this fantastic natural process.

However, we recently received an email from a reader about a specific worm he found in his compost, and he was wondering what type of worm this might be. Here is the picture we were sent:

In answering our reader’s question, we thought we would also point out a couple of the common worms that are used for composting.

For people who have an official composting area or bin set up (as opposed to just some organic waste lying around), they are more likely than not using red worms, which go by several different names, including redworms (as a single word), brandling worms, tiger worms, and red wigglers. (Of course, they also have a scientific name: Eisenia fetida.) Red worms are preferred for the task of composting because they consume a ton (they can eat more than their body weight in compost every single day) and reproduce quickly. Both result in more unhelpful waste being converted into helpful fertilizer, which is of course the goal of composting.

Another worm associated with the process of composting is the common earthworm (more precisely, Lumbricus rubellus, which is actually one of many different species of earthworms, but that’s neither here nor there). Unlike red worms, earthworms are generally not specifically acquired for one’s compost bin. While they breakdown organic waste and convert it into nutrient-rich fertilizer, just like red worms, they do it at a slower rate. If you come across some accumulation of organic waste that is not part of a compost operation, there is a good chance you’ll find some earthworms, but not red worms, in it. You might also find earthworms in compost bins dominated by red worms, however, as earthworms are more effective at breaking down organic waste that is already partially decomposed.

And what about our reader’s question? Given what’s been said so far, it is likely that our reader simply found one of the two worms described above, most likely the red worm, as the reader seems to have a full-blown composting operation going. His confusion may have arisen from the fact that the worm he found was quite small, but this probably just means that the worm was early in its life cycle. Red worms, after coming out of their eggs (which, interestingly, are actually wrapped up in a cocoon), are a pale yellowish color, but as they mature their bodies take on a brown hue. These traits more or less match the appearance of the worm in the picture our reader sent us, so it seems likely that they came across a developing red worm.

So, if you find a worm in a composting bin, it’s a probably one of the common worms that are found in composting bins, even if it looks slightly different for reasons of age.

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