Too Much heat?...

[Green Dumb]

The pictured plant is a Northern Lights that is about 7 wks. Old. Within the last few weeks older growth is canoeing, new growth looks great. 300w LED w supplemental CFLs. Temp at top is around 73 and drops to 60 or so at night. Humidity has been an issue around 40%. Have been looking everywhere online for an answer, but nothing consistent. Not sure if heat is the problem, humidity, Mg def. or what? Plants are in Vermafire soil and recently started lightly nutting it with bio thrive grow 4-3-3. Please advise.

 

[Dr. Who]

Canoeing shows heat and/or moisture stress. That would be lack of enough moisture for the plant to transpire at the rate it needs to. This also is the "tell" that the heat is to high and the plant is trying to transpire more to aid in the cooling of the plant.
By your listed heat #'s , I would look to the moisture the plant has available in it's growing media first. Be SURE those temps are accurate. I see that it's under an LED so "felt" heat is not it, but ambient may be working here also, if the temps are higher then you list.
You maybe have some dry "spots" in the media. Be sure to water enough to cover all area's of the media. Make sure the bottom of the pot gets wet!

Nice looking otherwise!

 

[Green Dumb]

Canoeing shows heat and/or moisture stress. That would be lack of enough moisture for the plant to transpire at the rate it needs to. This also is the "tell" that the heat is to high and the plant is trying to transpire more to aid in the cooling of the plant.
By your listed heat #'s , I would look to the moisture the plant has available in it's growing media first. Be SURE those temps are accurate. I see that it's under an LED so "felt" heat is not it, but ambient may be working here also, if the temps are higher then you list.
You maybe have some dry "spots" in the media. Be sure to water enough to cover all area's of the media. Make sure the bottom of the pot gets wet!

Nice looking otherwise!

Thanks Dr. Who. I have been pretty conservative in my watering to date. I'll give a good soaking and see what happens. Cheers

 

[Zomgshaman]

Yup sides curling up def heat stress.

 

[*BUDS]

Either heat stress or light is too close.