Is it possible to breed nightcrawlers (Lumbricus terrestris)?

Question

I'm looking at trying to breed earthworms, specifically Nightcrawlers (Lumbricus terrestris) also called dew worms. Part of the reason I'm specifically interested in keeping nightcrawlers as opposed to the smaller species of earthworms called red wrigglers (Eisenia fetida) is the red wrigglers produce a defensive slime that stinks and can make snakes sick.

I think it's easy enough to keep nightcrawlers in a container of organic soil in a cool place, as it's commonly done when keeping them for fishing bait. But I've seen on television the nightcrawler "farms" that collect them to sell for fishing bait just collect them from a big empty field. I'm not sure if that's a logistics issue of how many they need to collect, or if it's an issue with breeding them in captivity.

I was hoping to keep and breed them in a container kept in my basement. Like most live food they can get pretty expensive to continuously purchase from the store, and I don't really want to collect them from my backyard in case of exposure to pesticides.

Is it possible to breed nightcrawlers, or is there a reason it isn't something people do?

Answer 1

Canadian Nightcrawlers specifically are very tricky to breed in captivity. This is because they are what is referred to as an endogeic species. This means they like to dig deep burrows (5-6 feet deep) and live in them. They feed by pulling organic matter into these burrows and feeding on it inside the burrow. They also prefer a pretty cold environment (temps arout 10 deg C) and do not do well with heat (temps above 18 deg C). In addition, they breed very slowly in comparison with other earthworm species and can only live in a pretty low population density.

There are worms that would be far better alternatives that you can fairly easily grow at home. African Nightcrawlers and European Nightcrawlers are both good options for growing bait at home. Red wigglers are probably the easiest to raise but they are smaller than the others. Europeans Nightcrawlers are more cold resistant so that may be a solid option if you live somewhere where your basement might get chilly in the winter.

As far as how to raise them, it will be pretty much the same for all three. These species are epigeic meaning that they prefer to live in the top shallow layers of decomposing organic matter. To prepare a home for them, acquire a container that has at least 4 or so square feet of surface area and a foot of height. Fill the container with about 2 inches of bedding material. This is akin to browns in composting if you are familiar with this. Shredded cardboard, dried leaves, coco fiber are all suitable options but you can use whatever you have on hand. Make sure it is very moist but not dripping wet. Then you will feed them by burring some food scraps in the beeding.

How often you feed depends but check on your bin and once the food from your last feeding is gone feed more. Overfeeding can lead to a lot of problems so at first air on the side of underfeeding. Often worms will try to escape at first when introduced to a new bin so you may need to keep the lid off and keep a light on over the bin while they get adjusted.

Hope this helps, there are lots of good resources online to help fill any gaps I missed.