I like to use fleece in a bag shape, a quick tack up with some thread around 3 sides, but leaving a tiny hole ont the bottom side, and I plant my baskets up early in the greenhouse then when its at that time you are swithering or not if its safe to put them out or not, I slip the hanging basket chain hook through the hole and hang it up outside in situ, then I can pull it over the basket quickly at night, then its just as easy in the am.You can buy something similar but they are expensive.
