Help us help you... What is your watering schedule, what nutes and how often are you giving nutes? soil looks very dry at the moment. what kind of lighting?
i have been watering every other day to allow the soil dry.....just started them on FF Grow Big 1.5 tsp per gallon.....and i use 4 23 watt 6500k CFL's for my lighting
Do you have the FF 3 pack? Looks like a slight deff to me. Make sure you are adding Big Bloom with your Grow Big. 1tbl the stuff looks like chocolate milk. Should be adding this to your water once a week as well all the way thru leach.
A quick look makes me think over fert. are the leaves crisp? If you can do an pour thru test and determine the EC if high flush with strait water RO if possible