A reader wrote to us a while back about some white worms she is finding in her composter (that is, a device used for composting). The white worms appear to be multiplying, and she is worried about the red worms that are part of her composting operation. We believe that the white worms our reader found are actually, well, Whiteworms. “Whiteworms” is the common name given to the worms that go by the scientific name Enchytraeus buchholzi. (Whiteworms – sometimes spelled as “White Worms” – are also called “Grindal worms.”) The reader was wondering if the Whiteworms she found are harmful to her red worms, and she is also wondering if she can get rid of them without harming her red worms.

Unfortunately, the reader didn’t send us any pictures of the worms she found, but we can tell you that Whiteworms are extremely small, probably no more than two or three millimeters in length. When placed next to, say, an earthworm, the earthworm looks like an anaconda, and the Whiteworms look like earthworms. Despite the difference in size, Whiteworms are actually somewhat closely related to earthworms because they are both members of the subclass (formerly a class) Oligochaeta.

It is not strange that our reader found Whiteworms in her composter. They thrive in rich organic environments, which is exactly what compost heaps are. If you add some acidic matter (like the scraps of citrus fruits) to a compost heap or worm bin, this is known to attract Whiteworms, although they cannot survive in soil that is too acidic (i.e., less than pH 5). Starchy materials, when allowed to ferment in a compost heap, are also said to attract Whiteworms. When Whiteworms are not in compost, they like to live in soil that is fine and loose and holds water well.

Fortunately for our reader, Whiteworms are not harmful in a compost bin or heap – they shouldn’t interfere or otherwise compromise the work of the red worms in her composter. If our reader really wants to get rid of them, she will likely have to carefully monitor what types of materials she composts, and this might be too high a price to pay to get rid of creatures that aren’t hurting her composting operation. As we said above, a few different foods attract Whiteworms, so we suppose these materials shouldn’t be added to our reader’s composter if she wants to get rid of them. She definitely shouldn’t add a piece of bread soaked in milk to her compost bin, as people who are trying to breed Whiteworms (they make excellent food for fish in aquariums) add this to their breeding container.

As far as we can tell, the white worms our reader found in her compost bin (or compost heap or whatever it may be) are, indeed, Whiteworms (Enchytraeus buchholzi). The presence of Whiteworms in her composter should not harm her red worms, so she needn’t worry about getting rid of them. If she does want to get rid of them for whatever reason, she will have to track what she adds to her composter, noting the materials that bring a wave of Whiteworms and then exclude those materials from her composter in the future.