I like this set up for pots you can't tip. Hard to tell from the pictures, but do you have hardware clothe on the bottom too? See, around here, living in this virtual wildlife sanctuary I would have to do that. Otherwise, I'd be building a Grand Hotel for voles--complete with a lily bulb buffet. You can thank your lucky stars you don't have voles. Twenty years ago, I didn't but then one year--BAM--they hit me like a storm. That day comes as a completely disgusting surprize. If you don't have it screened off, I would strongly recommend you should, Rick, because you just never know when that day will come. And, golly--I don't want anyone to go thru that sick disgusting feeling I went thru the first time they got me.
I calibrated a couple thermometers for 32'F this morning--maybe post a couple pictures.