So this weekend, we pulled out some of the ragged tomatoes that aren't producing any more, added some amendments to the soil, and put in some winter beet seeds. I've never tried this before, so hopefully we will get some useable beets in a couple of months.
Something like this:
Beets are great because not only are the beets tasty, but the greens are just as good.
Probably only works in a hot climate like ours, where you have a mild winter. I'll keep posting on this, hopefully with good results.