I can only guess how hot it is on the roof. Yesterday I put up an overhead block (sheets), but Art reminds me the sun is sinking lower in the sky and this tomato line-up will continue to get blasted by the south sun.
I was slightly heartened to note that we haven't had this kind of heat since 2005, before we started growing on the roof. Which doesn't do much for the stir-frying plants up there, but might indicate we need to consider further steps to shade the tomatoes.
The eggplant seem more heat-tolerant