Here in Scotland I strip and rebuild the coup in the green house over the winter months. An excellent opportunity to sterilize fully. Having removed a bottom corner pane of glass I replaced with a slide up door which I only open when frost & snow is lifted. They benefit from no chance of a draft, increased temperatures in sunlight and the soil dries out, which also stores heat which is released at night and they pick the green house clean of potential weeds, pests and fertilize the soil for the growing season. I scrape and then simply dig the green house floor over every couple of weeks whilst they are in residence. Kick them out mid to late March, burn sulphur in the greenhouse to sterilize it and clean/ sterilize the coup again. Not as much work as it sounds and well worth it. So maybe if you have a greenhouse doing nothing over the winter months.... Might be worth a thought?