Iam just over 3 weeks into my first grow, wonder woman from seed. Plants seem very healthy and bushy and i thought i was doing really well. The last 2 days my bigger 2 plants have the tips of the leaves curling down like a claw(really only the bigger fan leaves that are on the 5th set of nodes not all) i dont really know if this is a problem. I have been looking on net but it seems it could be many things. I have ruled out nute burn because although there are a few tiny burns on one or 2 leaves most are very green and healthy looking.I was thinking maybe heat stress or my ph, my soil ph is just over 7, maybe i shoulkd try to bring it down to 6.5?? Or as its only affecting the bigger 2 it could be heat stress?? temp is about 81 on the tops of them big ones although i do have a fan blowing over them so they could be feeling less iam not sure. Take a look at pics and see what you guys think. Maybe iam worrying over nothing. Cheers