premature yellowing of sun leaves???

hows it going fellow greenfingers???ive been having a problem with my system/growarea,my sun leaves seem to be yellowing a slight bit to early,maybe just a week and a half into a ten week cycle,i think it could be a lack of humidity and maybe the atmosphere is too dry,i have made a slight adjustment from my old growroom to this one which has slightly larger dimentions,to cut down on the chance of mould/budrot and the humidity has dropped???can cloned plants get used to and thrive in the one environment??then when slightly altered they stress???im no scientist so im looking for a few other opinions please????nft and nutrient stable and does not need any extra trace added.would appreciate your responce thanx!:thumbsup: