“Can you grow red wigglers and nightcrawlers together? Where the best place to get the worms? We want to raise them as a class project to learn about science and ways to help the earth and to help plants grow.” ~ SmithWood Girls
That is a great question, girls!
I have sneaking suspicion that you might be referring to the Canadian Nightcrawler (Lumbricus terrestris), when you use the term ‘nightcrawlers’ so I will provide answer based on that assumption.
I will however also talk about growing European Nightcrawlers (Eisenia hortensis) with Red Wigglers (Eisenia fetida), since some people are likely wondering about this as well.
The Canadian Nightcrawler is a soil dwelling worm that is very popular for fishing due to its large size and the relative ease with which it can be collected (especially at night, during or after a heavy summer rain shower). Naturally there are a LOT of people who want to raise them for their own personal fishing needs, or to be sold as bait.
What many people don’t realize however is that this species is not very well suited for life in a confined worm bin. In the ‘wild’, L. terrestris makes deep burrows down into the soil and lives a rather solitary life. They come up to the surface (typically at night) to feed and to mate, but most of their time is spent burrowing through the soil.
I certainly wouldn’t say it is impossible to breed them in captivity, but you would need a really large system, filled with soil and maintained at relatively cool temperatures – remember that down below the surface layers the soil becomes quite a bit cooler.
If you WERE to try and raise them in captivity, the ideal system for them would definitely not be ideal for raising Red Wigglers (aka Red Worms). This species of worm is adapted for a crowded life in very rich organic matter, such as that found in a manure pile (pretty well their ideal habitat). They do not create burrows, and while they CAN be found in and on top of soil – typically there needs to be a significant source of organic matter nearby in order for them to want to stick around.
If you have an outdoor worm composting bin with an open bottom, you could technically have a system containing both Red Worms (assuming you add them) and Canadian Nightcrawlers – which would venture in from the surrounding soil. You likely wouldn’t see the nightcrawlers though since they would be hanging out down in the lower regions where the soil meets the organic matter.
The ‘European Nightcrawler’ is in fact a similar worm to the Red Wiggler (they are closely related) and they can technically be kept in the same system. For a fun school project you might try setting up a large bin and putting in 1 lb of each species then observing what happens.
Do they occupy the same areas of the bin? Do they seem to like the same food materials? Are they both reproducing – if so, at the same rate? These are just some of the questions you can try to answer.
I personally prefer to keep the two species separated, and I have heard some experts recommend the same – at least as advice for those planning to sell the worms later on. Aside from the fact that it can be a pain to try and separate the two species once mixed, I’ve read that Red Worms will eventually out compete the Euros.
If you do decide to try this out, it’s not a bad idea to also keep some bins for each species on its own just in case.
As for the “best” place to get your worms, the first place I would suggest looking is in your local area. This will save you having to get them shipped (which can be stressful for the worms), and will save you time as well. Worse case scenario, there are plenty of great suppliers that can be easily found online.
Hope this helps!