New grow worries

I am a steady smoker and i have grown my share of plants but i have never finished or harvested any of my grows and i just started a new grow a couple of weeks ago and i have been running my light schedule about 18/6 and i have been thinking about going 24/0 but anyway i was wondering why the older leaves on my two biggest babies are starting to curl under . there is no sign of dyin leaves or anything so i just figured that i was either watering them too much or there was some sort of nutrient deficiency. i have included photos (the quality is not that good so i'm sorry for the poor pictures) If you can tell from the blurred image i would greatly appreciate it if you could get me your thoughts. Thank you very much.:rasta: [attachment=o116350]

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well i cant tell whats up with the leaves, but i know for damn sure you need to get the lights closer to that... that thing is stretchin like a mo fucker... what lights are you using??

yeh, ive had a strain like that before, it was real bright green, and the leaves would form, then curl, the plants were still fine though, i think the strain needed alot more light, some plants, mostly sativa but occasionally hybrids, need more light, you can tell roughly how much light a plant needs by the shade of it, most indicas are alot darker, as they have more chlorophylls (photosynthesizing cells) meaning they can take in more light therefore they need less light, where as a bright green sativa (providing it hasnt got an N defficiency) will have less chlorophylls therefore needing more lumens (light units) so each cell can photosynthesize to its full capacity..

im guessin ur new, so its as simple as i can put it..:)

just put the lights as close as you can without touching the plant, about 2-3 inches away is good enough,