Leaves Curling/Leathery

I have never had this problem before, it's only on 3 of my plants in Flowering.
SoilMix - Sunshine Number 4
Nutrients - Humboldt Master A and B
Lighting - 1000 W HPS

The leaves are curling down, and look very leathery, yet are still growing, I know they are not rootbound, as they are in 5 gallon pots right now, and were transplanted before flowering, this is only week 2 of flowering. My question is what could be the cause? I thought it was over watering, so I let them dry out and gave them regular Ph water the next 2 waterings, yet I have not seen any change.

Well, I was hoping someone else would help you, but I guess that's gonna happen. So all I can do is give you my best guess that you need to raise your lights. those 1000w fixtures get pretty damn hot- so they should probably be at least 2 feet from the tops, maybe even 3 feet...

I betcha people would be more inclined to help out if you gave em some more info though:
http://boards.cannabis.com/plant-pro...ing-forms.html :thumbsup:

Usually if the edges are curling down its from under watering. If the edges curl up its from over watering.
Yeah with the 1000w unless you have a light mover you're going to want them to be no closer than 24 inches.

You might also be over fertilizing with nitrogen.