Arrrrrgh! The cayenne pepper didn't work at all. Next try: some sort of screen, or maybe bars (perhaps from old grills?). The plants do need to achieve their height, after all.
What really rankles is that the squirrels don't even seem to be using anything from the pots or plants, nor do they seem to be using the pots as toilets (thank goodness). They just seem to want to get in there and scrabble up the earth out of pure devilment!
I bought some mint today--hoping to get that going before I bring it inside. Fingers crossed that the squirrels don't 'molester' that too!