After looking at your pic and running over to rollitup.org i found this for ya...
Margins of the leaves are turned up, and the tips may be twisted. Leaves are yellowing (and may turn brown), but the veins remain somewhat green. >> Magnesium (Mg) deficiency.

Hope it helps

Nim
Nimbliez Reviewed by Nimbliez on . what is wrong with my 2 month old clone S=Answer if you grow traditional soil reguler soil E-indoor or outdoor indoors CSL-Soil type/brand I do no SCL-Anything you have added to the soil some hasta gro plant 6-12-6 at 1/4th to 1 gallon of water. SCLR-Soil or slab runoff pH I do no E-Water source tap E-Source water pH 7.something E-Age of plant1 1/2 to 2 months old E-Type of fertilizer hasta gro plant Rating: 5