I am using scotts soil w/o nutes but i have sand for the top 1" so it kills the gnats

Needs lime,give um these 2 things:http://www.google.com/products?hl=en...num=1&ct=title http://www.google.com/products?hl=en...num=4&ct=title For the gnats you can buy neem oil or yellow sticky traps........

what is ph currently?

Obviously nitrogen but this might be because of an insufficient root system which comes from over watering or because your pots are too small. I would definitely say you have a bit of a root issue with those pots.

sorry i have not checked this thread for a while umm my ph was i think 6.8 or so and i also upgraded my pots to about 3 gallon and now my plants still loose about a leaf a day but now they are 4' tall. I gave them nutes and plenty of water but still losing bottom leaves oh and they are not yellowing anymore just falling off and some are just browning at the tips not yellow! I will be putting them in 12/12 soon maybe in a week or less.