>>2091089Mine is a 7x12 cheap tent style greenhouse that i put on a treated lumber foundation and reinforced the frame. When the temperature drops below ~40 F I cover it with two tarps and turn on a small electric space heater. Even on the nights that were below the 20s, I don't think the heater came on more than 10 times an hour and only ran for a minute or two. I use an aquarium thermostat to regulate temperature.
