The easiest way to keep a worm bin active is to keep it inside. It is a constant temperature all year long, no need to cool in the summer or to heat in the winter. If the bin is kept well you won’t be overrun with insects and there will not be any unpleasant odors. Many people find unused corners of their houses that can fit a worm bin. My mother keeps her worm bin right next to her trash can in her kitchen and has never had a challenge. But perhaps keeping the bin in the house is not an option. For me I have far too many bins to bring them all in the house so I need to find other alternatives.
To keep your bin warm enough you will need to provide a heat source and insulation. If you just want to keep your bin alive insulation alone may be sufficient, but since I want to keep my bins active I need to find a heat source as well. A natural, microbial heat source is preferable. I have three large outside bins which I insulate with a layer of mulched leaves and a thick layer of shredded paper. I also cover the bins with plastic to keep the rain out and the heat in. It would be cool if I could have put the bins into the ground to provide additional insulation but we have an impossible hardpan so we are stuck with above ground bins and garden beds. The food you add will add heat but make sure you let the worms be your guide… they may be slowing down on their food consumption so the feeding frequency may decrease.
If the food and insulation doesn’t create enough heat you will need to look into alternative heat sources. For my inside bins I have several layers of Christmas lights on the rack. If you have just one bin you could set the bin on some bricks and put a wad of lights under the bin. You could drape a bin with lights. When I only had one bin I would put a heating pad under the bin for a few hours to get it warmed up. Monitor the temperature because if you have too many lights or a heating pad you can get the temperature way too hot. I have also placed sheets of plastic around our rack to hold in the heat we generate with the lights. This seems to keep the space in the 60’s without any challenge but our goal is 70 so now we have to get creative… More lights may be the option we go with eventually but for now we have been running a space heater while we are working on worm projects in the evening to get the temperature up.I have tried several other options in the past that could work if you only had one bin to work with. When I had one bin outside and I wanted it to stay warm I put a glass juice jar filled with water in the middle of the bin and would replace the cool water with warm water every day. Even though I was a pretty die hard worm lover this got to be too much when the weather got particularly nasty. I decided to try an aquarium heater instead. It worked pretty good just keeping the water a constant temperature and the worms gathered in the area around the jar.
I hope some of these ideas help you find a winterizing option that works for your worm system.
