So we don't need to heat unless it's maybe below 40 degrees, and then we can heat with sterno (!), candles, or a light bulb. I guess I won't heat tonight and see how it goes. Thanks everyone for the ideas.
Donna, I just thought of someone else who can answer questions about GH in our area. Eileen Weidner, of Weidner's Greenhouses in Leucadia is really helpful, and so are all the people who work there. I was there last spring, and I was so impressed with her impatiens baskets that I took a photo. Sorry for the poor quality, but I took it with my phone.
