canoe leaf?

[advocate]

Like any expectant father I look for the first signs of trouble, 5 weeks into vegging and I notice the newest leaves of my largest plant are starting to show an unmistakable "canoe" shape, the leaves are not curling downward but more so the outside edges of each leaf are curling inward and upward, sort of a tubular effect, (not quite to that degree), I guess it would be easier to describe if I posted a pic...what exactly causes canoeing? perhaps I should re-read the manual for newbe's

 

[Hick]

"Canoeing" and inter-veinal chlorosis are indications of magnesium defficiency. Plant Abuse/Problems

 

[advocate]

Thanks for the link Hick (very helpful)... I did move my light up, there hasn't been any discoloration of the leaves yet so I'm going to assume it was a heat and not a nute problem... damn things are growing so fast I'm running out of head room for the MH light... week five and they are nearly 3' tall, over a dozen internodes and this is the first sign of any problem... getting ready to go 12/12 and switching over from MH to HPS to finish...