Rust/Copper color on Leaves with Curling...

[mountain green]

This might be a possible air circulation problem, Co2 is admitted by dry ice frequently.
The leaves are experiencing a brownish/rust/copper color all over the edges and some of the leaves are curling length wise (up)-some are severe on the Fan leaves.
Mostly seen on "Chocolope" and some are seen on the "L.A. Confidential".

Any help would be appreciated, I have the Medical Marijuana Grow Bible but I am looking for more information.

 

[shdowlkr]

Potassium (K)
Action Mode
Helps plants overcome drought stress; improves winter hardiness; increased disease resistance; improves the rigidity of stalks; leaches from soil; mobile in plant
Deficiency
Reduced growth; shortened internodes; margins of older leaves become chlorotic and burn; necrotic (dead) spots on older leaves; reduction of lateral breaks and tendency to wilt readily; poorly developed root systems; weak stalks
Excess
Causes N deficiency in plant and may affect the uptake of other positive ions such as Mg and Ca
Comments
High N/low K favors vegetative growth; low N/high K promotes reproductive growth (flower, fruit); calcium excess impedes uptake of potassium

-K is possible.... What are you feeding with and how old are the plants in question?

 

[JayBee]

what is temp and rh? what medium? ph? ec? what stage of growth? c'mon, help us to help you :)