I did one pot yesterday and loosly taped a piece of greenhouse plastic over it. I'm going to have a lot more pots, and maybe will put one large piece of plastic over all of them. I have critters around the yard. I don't imagine the squirrels will be too interested in whats under the plastic but you never know. I tried direct planting acorns and hickories, and the squirrels dug them up almost immediately.
