it makes me giggle to see new growers freak out when 1 or 2 leaves turn a little yello or wilt and die ....lol...they always think somthing went wrong or somthing is wrong ...a plant will do its thing bend,stretch,retain water,lose water, drop leaves,turn a little yellow sometimes, think about it , all that plant knows how to do is grow UP...so its the grow tips that needs most of it attention when vegging and even more when flowering....Iv had a few plants look like they where almost completely dead from 1/3 of the plant from the bottom when flowering ....it was killing its self to make as big as buds as it could with what it had to work with ...lol...