An experiment in free GH heat I found some manure from 'Short' ponnies, I mixed it 1/2 and 1/2 with rough cut pine sawdust. added water to about a damp sponge level. I then placed the stuff in a green garbage bag and set it in my GH. For the first week the mixture, measure with a dial compost thermometer was about 50F Added some more water after about a week, the bag has stayed at about 60F for the last 3 weeks.. Last year my chiles didn't like it at 50F L.B.