How much money are you willing to spend??

A greenhouse heating cable could be purchased, buried 4 to 6 in below the surface, it should keep the interior at around 72 deg F. Probably cost around $30 if memory serves, and length is dictated by the sq. footage you are trying to heat. These are propagation cables for nurserymen.

If I were to go to all that trouble I would try and insulate the exterior with whatever is at hand-straw and bagged leaves sound great.

You could also feed something that causes bacteria to heat the bin- cornmeal comes to mind immediately- but any grain would work. I "am" a cornmeal freak!

Last, but not least - I would definitely start an indoor bin as quickly as possible to give a head start "if" the outdoor bin doesn't survive. And I would make it as large and as populated as permissable.

just some thoughts

bruce

I like this idea of the heater cable. I may check that out. I think I'll buy a green rubbermaid bin and get that set up too. I still plan on insulating it with bags of leaves.
Ok so why put the cornmeal in there? I don't feed them cornmeal on a regular basis and I thought they did better if they got the normal diet all the time? If I heat it with this "outside" source would I still need the cornmeal?

Thanks,
Vicky

I'm not proposing cornmeal to you. I feed it since I have access to waste meal and it seems the worms love it or love the bacteria bloom it produces!

I have kept a compost thermometer in the bins most of the summer (worms are in the house and temp usually stays at 78deg F.) After a heavy feeding of C.M. I can watch the temp go up to 85 / 88 deg. will stay that way till the meal is processed - Kelly told me that the meal is so nitrogen rich and in such small particle size that the bacteria can really bloom with it (and also raise the temps)-then the worms are there for the bloom. I think all grains will heat the bin during the decomosition stage, I just happen to have and like cornmeal.

This was just another thought about generating heat in an outside winter worm bin.

bruce

I'm a big fan of the indoor bin. I think that It would be much more convenient to toss the food scraps into the Rubbermaid in the kitchen than to trudge through the sub freezing temps to feed an outdoor bin. In our house, the amount of food scraps in Winter is much less than during the fresh veggie season anyway. My understanding is that the coccoons in your outdoor bin should be ready to go in the Spring.

I've never had (or desired) an outdoor bin, so take this comment for what its worth. I am too klutzy to try to maintain temps using thermal decomp, and too poor to heat an outdoor bin all winter, but that's just me. :)

Vicky, your idea of stacking leaf bags around the bin is a standard practice shown to be very effective for insulating outdoor systems in cold regions. In the absence of leaf bags old straw bales work very well, too, as does tossing an old sleeping bag over the bin. Remember that the top of the unit needs to be covered as well, as heat rises.

As long as you continue to bury feedstock in an insulated bin that has some mass to it (at least 2' x 3') bacterial heating will keep the system warmer than ambient temperatures. The mistake some make is to reduce feeding when it gets cold, thus reducing energy inputs that fuel biological heating. As ShenValleyJoe suggests, we tend to produce less feedstocks appropriate to worm bins in the winter, and we tend to eat more, producing less scrap, so keep an eye on the feeding rate to ensure you're keeping the system fueled.

Outdoor bins are employed year round in most areas of the US. Of course the worms will slow down considerable during winter as compared to summer, and sometimes essentially stop processing scraps, but worm bins are not killed, even in New England, Nebraska, and Michigan when the season turns cold. Your worms will do just fine!

Kelly S