It looks like the tall one has plenty more growing to do, so the leaves may be starting to yellow at the bottom under normal circumstances... If all of them are yellowing however, I think there may be a problem. What is your PH and what has the feeding schedule been? I also noticed wet leaves (maybe from the foliar feeding?) this is OK in the dark but foliar feeding the leaves can leave them burned if it is done under high intensity light... the best time to foliar feed is right before lights out...
I wouldn't hazard a guess without some pics in normal light, and some PH, nute and watering figures....
Keep it up and you'll have some nice sweet smoke as a reward! Good luck and grow karma sent your way!
Surf
The chunky short one is one of my favorite phenos of LR2, hardly grows outside the pot, and isn't just a bud on a stick either, good yielder, if you could get 20 of them all together you could pack a good tight space full of bud!
:dance: