You must do something. I think you used the wrong material for a bin. As you say, metal will get cold fast. Is the garage insulated? Could you build a wooden enclosure for the bin so that you would have a smaller space to heat? I sure would hate to have you freeze out.

Dave Nelson

Non-electric solutions are few. Is your cart wormery shallow...4-6"? Maybe I'm remembering a different set up. Anyway, one "natural" way to add warmth to a bin is by feeding controlled amounts of grain. A half gallon of cooked rice, for example, will get pretty hot as it decomposes. Bury that 3/4 down into your bin material and it will give the worms a campfire to warm their tails over. I've also heard a pile of beans and wet bread will do the same thing. Once the hot pile cools off, the worms will eat it. I haven't personally tried this, but plan to this winter.

Andrew

What about a germination pad held on the bottom of the bin? The heat should conduct through the metal and give the worms an area at an appropriate temp, for fairly low cost. The benefit is that you wouldn't have to worry about overheating or underheating them either. Most germination pads are easily adjusted to a temp around 70-80 degrees. And you wouldn't be wasting any energy to generate light, like lightbulbs would.

I would also consider putting some heavy blankets over the bin to contain any heat generated by the composting process. A compost thermometer would be a good idea, if you don't already have one, just to confirm where the temps are in various spots around the bin.

Warmth
Red Worms (Eisenia fetida) tolerate bed temperatures as high as 43C (109.4F). It is best to avoid letting your worm bed temperatures go above 30C (86F). Adults of this species have been known to survive being encased in frozen material, and the cocoons are well adapted to survive sub-zero temps for extended periods. The optimal temperature range for breeding Eisenia fetida (red wigglers) is 15-20C (59-68F), yet maximum growth (weight gain) occurs closer to 25C (77F), if you want to go fishing.

yes my bin is 6-8" deep I know it wasn't the best choice of material but it has worked very well ands my intent was to keep it in the warehouse at work that never got below 50 deg or so and I was also able to store in a conditioned warehouse bathroom in severe months... don't work there anylonger.... anyway their loss the company and the worms i GUESS... I was thinking sbout buying some rigid insulation board and glueing to bottom and sides. I use burlap at a top garage is not insulated and I am trhinking with the insulation and a plywood top might just get me buy darn it is going so well at the moment.. and yes I have red wigglers

Insulation all around will probably be enough. Why not use insulation for the top also? Lighter than plywood and better insulation. :-) Your regular feeding may provide enough heat, but you can mix in those grains I mentioned if you need to. I agree with the advice to get a probe thermometer to check actual bedding temps. One used for the kitchen is good enough...just make sure it goes down to 32F/0C.

Here is a link that might be useful: probe thermometer

so how long will 1/2 gallon of cooked rice last in there i assume it will do the job untill it is visuly gone?