greens in plastic tunnel after a night at 22*F

I went to my garden to check on the plants after an icy cold night. Everything looks surprisingly good. Even greens outside of the plastic tunnel. I picked the last head of the lettuce growing outside. Its a big head of green butterhead was covered in lightweight row cover. There is some uncovered bok choi that I will remember to pick and eat for dinner tomorrow. Our next salads will come from the tunnel.