Boulder Vermicomposting

Preparing your worm bin for the winter

November 5th, 2009

Winter is coming, at least in the northern hemisphere, and that means that you need to spend some time thinking about your worm bin.  I had a reader (Linda, my future mother in law) as about this.

Now, if your worm bin is inside, the only thing you need to do is make sure it can handle your food waste.  If you have been splitting your feeding between an outside and inside worm bin, or an inside bin and a compost pile, then the inside worm bin probably doesn’t have the population to handle all your waste.  Up the feeding slowly, and throw some of your food waste away.

If, like me, you have an outside worm bin, then you will want to do a couple of things.

1. Clear out some of the vermicompost and castings.  This is the perfect time to do so (or, maybe last month was).  Your worms have been working hard all summer, and you’ve probably had the chance to give them a lot of food.  You might have been so busy enjoying the summer that you let them fill up their bin.  I took out about 18 gallons of worm castings and vermicompost (and I’m sure, a few worms and cocoons) from my worm bin, and put it in my garden for next summer.  This will open up space for you to feed the worms for the winter.
2. Make sure the worms have the ability to ‘go to ground’.  If your compost bin is in contact with the ground, the worms can retreat into the ground if the bin starts to get cold.  This is good advice for the summer as well.  If you have an independent bin, you can bury it in the ground a bit.  If you have your worm bins on a balcony, you might want to bring them inside, at least on any nights where it is going to be freezing for a long period of time.
3. Make sure you can still feed your worms.  Your worms can last for weeks without food, but not months.  Also, the composting of the food can provide some warmth to counter balance the cold.
4. You can provide them insulation (here’s an example of using straw to insulate against the Canadian winter), but make sure you can get in and feed them at least once every couple of weeks.  I insulate them by making sure plenty of leaves are on top of their food.  (Fall is also a great time to pick up leaves to provide bedding for your worms all next year.)

That said, I live in Boulder, Colorado, where we have some cold weeks and some warm weeks every winter.  (We’re USDA zone 5.)  And by warm, I mean ‘above freezing’.  If you live in zone 8 or zone 9, you probably don’t have to worry at all.  And if you live in zone 1 or 2 and want to keep worms outside, I’d suggest heavy insulation, or moving them to the garage.

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