Even in our cold Canadian climate, worm composting can be successfully accomplished outdoors year after year, with little hassle.
The Proof is in the Compost
You may wonder how this is possible. Glenn Munroe, a researcher at the Organic Agriculture Centre of Canada, was also curious.
He studied what was happening inside the long windrows of worm compost on a farm in Nova Scotia. What he found was that, during the winter months, the worms migrated within the windrows so that they were located at the center and towards the southern end of the heap (the warmest spot). He also found worms that were almost completely encased in ice (only having room to move their heads) could be thawed out and continue to function normally. He concluded that the worms die from freezing only when they’re prevented from eating! He documented his findings in a 56 page manual titled the Manual of On Farm Vermicomposting and Vermiculture. (see page 15)
Cryogenic Worm Eggs!
Previous studies by the Nova Scotia Agricultural College (NSAC) had confirmed that the cocoons or “eggs” of compost worms can survive deep freezing for extended periods of time and still hatch out healthy and hungry baby worms.2
So even if your worms do freeze or “die by starvation,” their cocoons will remain and hatch the following spring!
This is why many gardeners have been pleasantly surprised to find thriving populations of compost worms in their outdoor bins for many years after introducing them.
Important Considerations Before You Begin
That said, you can’t throw worms into an outdoor bin all willy nilly and expect them to survive.
There are a few worm hazards that must be considered before you begin.
Here are the 7 Habits of Successful Outdoor Vermicomposters.
1) The composter must be stationary. Not the rolling or turning kind.
2) It should be placed in a shady location to avoid overheating.
3) Go easy on the grass clippings as overheating can occur through their decomposition.
4) Place a wire mesh beneath the composter to prevent voles and moles from snacking on your worms.
5) No need to turn your compost, the worms will do it for you!!
6) Remember to add a carbon source (like newspaper) on occasion to give them a balanced diet.
7) Avoid adding citrus, onion and garlic waste as these are organic pesticides.
As long as you keep these conditions in their favor, your worms will never leave you.
In fact, they’ll stay right where their food is located.
Research Articles Mentioned In This Post
1) Manual of On-Farm Vermicomposting and Vermiculture by Glenn Munro, Organic Agriculture Centre of Canada
2) GEORG 2004, Feasibility of Developing the Organic and Transitional Farm Market for Processing Municipal and Farm Organic Wastes Using Large-Scale Vermicomposting Good Earth Organic Resources Group, Halifax
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Question: I have a lot of sow bugs in my worm bin. What am I doing wrong? And how can I get rid of them?

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