Unfortunately, it got so hot soon after the lettuce sprouted that it went almost directly to seed as soon as it was big enough to eat. It didn't matter that a month later it cooled off to near normal temperatures, perfect for growing lettuce. The lettuce had had it. And, it was to late to plant more because it would heat up again and I'd just waste the seed.
So I decided to let the seed lettuce mature and reseed itself for this fall. That way I wouldn't have to plant another batch of seed at the wrong time. Sounded like a good idea, but it seems the lettuce had another idea. Instead of putting out seed and maturing in a nice patch, it decided it wanted to keep growing larger and larger, and the seed heads started laying down into the other vegetable areas.
Yesterday, I decided enough was enough and pulled the lettuce out of the garden completely. I could not rehabilitate the lettuce so it had to go. It was a hard decision to make but in the end I think it was the best one. Under the sprawling, and unruly, lettuce I found two watermelon sprouts and a small, unhealthy looking, tomato plant. Now, with the lettuce cleared out they will get much needed sunshine and rain and will hopefully grow to be nice productive members of the garden.