Since the only place I have with enough space to germinate my seeds is in my uninsulated attic, and I didn't want to spend a fortune either heating the whole room or buying a grow tent, I got myself a cheap, indoor greenhouse and wrapped a rescue blanket around it. Seems to work ok so far. I have four heating mats running 2 1/2 hours on, 1/2 hour off, and the soil temperature is 30°C. The seed tray in the picture was started a week ago .