Clare_CA

I think anything above freezing -- 32 degrees -- will be fine for them. Warmer is better, of course. My greenhouse is unheated and stays only a few degrees warmer than the outside at night, and the air temperature definitely gets down into the 40's. The nice thing is that, during the day, the greenhouse really heats up to very high temperatures, which warms the soil, and so, while the air temperature might be in the 40's at night, the soil temperature will be warmer and slower to cool to match the air temperature. Of course, proper drainage and not overwatering is important during the winter. My variegated bananas are in my greenhouse now, but I'm going to be moving them to a sunroom that we are in the process of building for the winter just because I think they will be happier staying at an even temperature rather than the temperature fluctuations that the greenhouse has. These are newly transplanted variegated bananas, which, I imagine, are more susceptible to rotting than established ones. HTH