Message from Joel:
Hello, I was on a forum and saw a vermicomposting question. They wanted to catch earthworms to use in their vermicomposting. I referred them to your site and suggested the purchase their first batch.
One poster suggested just setting up a pile of leaves and scraps and catching wild red wrigglers. This got me thinking.
Being primarily a compost worm and with us not having lines of compost from coast to coast for them to travel in, how likely would it be for someone to “catch” any red wrigglers this way.
Also, my though was what are the chances of getting some worms or eggs if you went to a big box and bought a bag of organic compost and added to the bin. I’d think you’d have issues with the bag getting too hot and killing them, but I didn’t know if you’d ever experimented with this or possible the same idea, but straight from a whole seller.
These are some great questions!
There really isn’t such a thing as a “wild” Red Worm – well, at least not the type of “Red Worm” we are after. Eisenia fetida/andrei worms are very closely associated with human activities, most often being found on farms (in old manure piles) or in compost heaps/bins within town/city limits.
Another type of “Red Worm”, Lumbricus rubellus IS more of a “wild worm”, and there is a pretty good chance you could attract them with a heap of old leaves (assuming they are found in your region) – but they are NOT an ideal worm for vermicomposting. They don’t reproduce nearly as rapidly as Eisenia fetida/andrei, they’re not as well-suited for processing rich organic waste materials, and they don’t have the same sort of tolerance for hot temperatures and crowded conditions as Eisenia worms (although they are much better suited than typical garden/lawn worms).
The other potential “problem” with L. rubellus is that it has been implicated as a serious invasive earthworm species in some regions. Academic research has shown that it can rapidly populate and consume forest leave litter, altering the balance of forest ecosystems (in locations where it wasn’t previous present). Obviously this isn’t really an issue if it is already in your region, and you don’t have plans to share your worms with people in other parts of the country – but still worth mentioning.
You can learn more about the topic of invasive earthworms here: Do Composting Worms Pose a Threat as Invasive Species?
The good news is that it is relatively easy to distinguish Eisenia worms from Lumbricus worms. As you can see in the image below, Lumbricus worms tend to have more of a pale, uniform coloration without striping of any kind, and a tail tip that is much more flattened, whereas Eisenia worms have more of a variable coloration, with at least some (in some cases, very distinct) banding. The Eisenia tail tip is more conical in shape and will have some coloration.
If you happen to live in a city/town (or even region in general) where there is a lot of composting activity and/or livestock farming, there may be some Eisenia worms close enough that you could attract them to a deposit of rich organic matter (my recommendation would be aged horse manure).
Regarding natural dispersal – the compost highway idea is funny, but I agree it’s obviously not how composting worms move from place to place (lol). In the case of farmyard manure piles, my guess is that the worms can end up in an isolated heap when a bird carries cocoons or small worms on its feet. And then they can likely just gradually make their way to neighboring farms via typical earthworm movement (during rain storms etc). Similarly, once someone starts using Red Worms in an outdoor compost bin the worms can then gradually move to other composting systems in the area (etc).
As for big box store compost having worm cocoons – the chances of that are VERY slim, unless they happen to be carrying an unsterilized “worm castings” product. In the case of their bags of “compost” and “manure”, these would have definitely gone through some form of serious sterilization process (it’s doubtful these stores would want to take any chances, dealing with as many customers as they do).
Hope this helps!