Q: I have wanted a greenhouse for a long time and the time has come to get one. Do I need a heater in my greenhouse? I want to overwinter many of my plants there.
A: If your greenhouse is built away from your house, you’ll need a heater. In addition, if you want to have plants there in summer, you’ll need a cooling system. If the unit is small, climate conditioning can be accomplished with an electric heater and a small air conditioner. Don’t forget to factor in the cost of running water and electricity to your greenhouse. I’ve assembled several good references at xrl.us/greenhouses.