Sick Papaya's Need HELP!!!

i got about 9 papayas going in organic soil. Dont know the temp cause i didnt get my temp guage but i know its cool in there because i have an AC set to high blowing right on them. So temp is not an issue. The ph is btw 6.4-7.0. The issue is the edges of the leaves are folding up. The plants look very healthy otherwise and i can see there growing everyday. any idea what the problem could be? I gave them a half a spoon of epsom in a gal of water last friday but the leaves still look like that. I fed them 200-350ppm last thursay with mircle grow......can someone help me out there?

Im not positive but i think that a papaya plant would like the heat, if the temp gets below around 65 they will be stunted and could die