Earlier in the summer I planted a few pak choi (or bak choi) in another raised bed which are doing good. There is also some self sown lettuce in the same bed that we'll cultivate and harvest as long as we can. It's been my experience that lettuce sown in the fall will survive each year until spring even if it doesn't put on growth. Once spring warms up the lettuce has a great head start. I'll place a couple hoops over this smaller bed as well and cover to encourage growth for a longer period over the winter.
Are you growing fall or winter greens this year?