I'm going to attempt growing lettuce outdoors this year using a floating raft setup. I will use oasis cubes for propogation. The nutrient solution will be 7" to 12" deep and will be aerated via large airpump and air stones. I have a few indoor grows under my belt using deep water culture, both culinary herbs and salad greens.

Here in Georgia, it gets up to 100 degrees with high humidity. Because of this, I understand that I won't be able to grow through the heat of the summer, but what I'm curious to find out is what kind of temps do you find to be about the top for lettuce growing? I do plan on providing a 50% shade screen. I thought about adding a chiller for the nutrient solution but then read in the Growing Edge that plants don't like it when the nutrient solution is more than 5 degrees lower than the ambient air temps. Do any of you have experience to counter that claim? Perhaps you had 95 degree heat and chilled your nutrients down to 80 degrees or so with good success?

The greens I would like to grow are things like romaine, green leaf, spinach etc.

Thanks in advance!