Dear All, I think Rodger has raised some excellent points. I don't live in a cold climate, but I do have a green house and I start a lot of seeds in my greenhouse and move other plants in there I know won't want to be rained on as much as they would be outside. The humidity is very high during winter. Most years my husband adds plastic over the top to make it more water tight which really helps. In addition after having a lot of disease one year when we had 30 inches (762mm.) of rain one month I have a fan going all the time. I think it really helps. And I open the door on days when it isn't raining. Air circulation is so important. Since I have been doing that things are much better. Mary Sue