My white widow are in 6th week of flowering and they are turning yellow from the top down. I have read every where and all I can come up with has been when folks plants are turning yellow from the bottom up. What would cause an otherwise perfect plant to turn yellow from the top down? I have about a week and a half left for them to mature I think. Nirvana said 6-8 weeks. Thanks for any help and I hope I am not hi jacking this thread. Peace