Lettuce & Cold Temps

From what I can tell from looking into several different sources Lettuce can easily survive cold temperatures. I planted my lettuce and carrots from seed straight into my SFG about 3 weeks ago and I have lots of small lettuce leaves in my squares. Tonight it is supposed to get down into the upper 30's and being in Houston I have no idea how to take care of my garden in this weather. According to weatherdotcom the temps are supposed to reach the 30's just before sunrise and then warm back up. I held off on planting tomato seedling this past weekend because they would handle the temperature well. I think the lettuce and carrots will be fine not being covered while the temps dip down for a single night. Any helpful advice? Should I water them tonight?

H TX, I can't tell you your lettuce will survive. However, I can say I've had my lettuce out at, or a tad above and below freezing and even buried in snow, with no ill effects other than possibly pulling off a leaf or two at most. This is with hardened off lettuce. Not little seedlings or lettuce without much growth. YMMV.

I think you're worrying about upper 30s much more than your lettuce will. My lettuce encounters at least lower 30s and often upper 20s every spring without harm. Agree on the appropriately hardened off comment (e.g.-not lettuce you raised indoors and just planted out about freezing temps; but upper 30s should be no problem).

If you have some heavy plastic, you can simply cover them at night if you're worried about the seedlings. You don't even have to have a special frame set up. Just put in some sticks or something to raise the plastic up enough to clear your seedlings and drape your plastic.

We also keep glass and plastic jars in the garage to use as cloches (little terrarium like coverings) to protect seedlings from unusual cold spells.

The lettuce itself if old enough will more than likely sail through