Symptom: leaf edges curling up...

[2RedEyes]

I have these two autoflower plants same age, both grown from seed in the same soil FFOF. I’m using greenleaf nutrient “MegaCrop”...They are being grown outdoors in 5 gallon smart style pots...both are nice and green without any burning leaf tips or such... one has these leaves curling up along their sides...a little looking online says this may be heat stress...It’s been hot here for several weeks and they have not been doing much growing and I’m assuming that heat is the culprit there as well...I’ve been watering and feeding every other day...The other plant seems happy as can be and the only issue with this one is these curling leaves...I don’t think there is a calmag issue as this soil should be good...I have not been doing any ph adjustment, my tap water is about neutral @7 and PPM’s in the tap are 037...I use only dechlorinated water in my garden... should I put up some filtered shade during the heat of the day? The high’s have been mostly mid 90’s with a few 100’s and low’s are 60-65...they are 8 weeks old tomorrow so they are closing in on the finish...I’m not really too worried except I’d like to know what the issue is and I have another pair just starting out and I’d like them to both grow larger and not have the same issue...I know that autos will be smaller but they should be easily able to attain 36”...the smaller is barely a foot and the larger almost 2 feet...Both are making some nice buddage...
They are both high CBD strains from Dinafem though different strains...Maybe it’s just too hot here in the summer for growing weed...thanks for your help...

 

[umbra]

yes, heat stress. I would try some 20% shade cloth

 

[2RedEyes]

I got something to use as shade cloth but it’s gonna be a bit cooler for the next couple days so I think I’ll wait and see for now... I’m probably just a few weeks from harvest...