I have been thinking about a greenhouse for a while now.. But living in Quebec and the winter temperatures going to -30C, I know it is not going to help me grow crops in winter if I don't heat it. Of course, cost of heating a greenhouse is incredible and a bit ridiculous (my lettuce would probably cost about 15$ to produce!) ... so I thought about putting my hot compost pile in the greenhouse. While Googling this, I found that Bioshelters existed and now I am all exited!! A bioshelter is like a self-heated greenhouse that also houses pets - chickens and rabbits, sometimes even fish. The animal's bodies give heat to the building, as well as the poop.. I also think I could heat the greenhouse partly by using large water barrels painted black, so the water would heat during the sunny time of the day, and release heat during the night. I'd put a hot compost pile outside or inside (not sure) and probably use pipes from the compost pile to the greenhouse to distribute heat. I would like to know if anyone is doing anything similar? I've found success stories of growing crops all winter - without electricity - in Massachusetts. Not too far from me, but still warmer climate in winter, not 100% comparable with Quebec!