Chilly night

Night before last we hit our first 32 degree evening. I didn't have the greens covered and I lucked out--nobody froze. I had the hose going first thing in the morning just in case. Last night I was more cautious and had the sheets over them so, of course, it only hit a low of 40. I have four 55 gal.  barrels of water to help hold heat but it only goes so far. Eventually everything is going to freeze. The whole thing is an experiment at this point anyway. How much abuse can lettuce and kale take? These big lettuce plants have been producing since August--no sign of them going to seed yet. I am going to stake them up and keep picking as long as possible. There are two other beds coming up so if I can keep jack frost away there should be good eating. We are going to get our straw bales on Monday so I can reinforce the insulation factor.