plant top leaves are cupping badly

hi i have a plant, its top leaves are cupping badly started happening a few days ago and seems to be getting worse, i think its mg def, anyone have any ideas?

Whats the temp 90+ ? they just look like they are praying for cooler temperatures to me Nice thermometer have same one in my room .

thnx, will move fan towards top of plant, temps are at about 80-85, with light, and about 70-75 with lights out.

Ya I had the same problem with my room, my temp was over 80 sometimes up to 90, I was freaking out because I had no room for more fans and the leaves were cupped very bad and crisping at the tips but what I really needed was another exhaust fan that did the trick instantly only got the temp down to 80 but it wouldn't get any hotter and they liked that just fine (my avatar is a pic of the above mentioned crop of church)

I believe that "cupping" is more likely moisture stress (of course, that could be related to temperatures, but humidity is the key, they cup because they want it more humid).

Looks like heat stress but you should also ensure your PH is correct.

i do have an inline fan 200cfm, and fresh air vent for air to come in, also 16" osillating fan. humidity is between 38-50, but mostly stays at 40, temps are good as well. they are cupping but not crispy, leaves still seem healthy, its under 400w hps, 12/12 on its 6th week of bloom, in a 4x4x6 room, the strain is 80% indica 20% sativa, nl x budda, says its a 8-9 week flowering period, the only thing from what i\ve been reading i can tell is that it is a mg def, with the cupping and all. I guess i will give a good flush and then start them on 1/4 nute feeding every watering and see where that takes me, this is my first grow, so iam learning as i go.