Im wondering if my plants need nitrogen. only fed once, they are end of 4 weeks now. The white widow showed slight clawing 3 days after feed so I didn't give anything again. I noticed though that the lower fan leaves are slightly getting pale towards yellowing possibly..certainly not as dark as they were a week ago. Upper growth seems ok. Was wondering if a plant can still display the claw from a previous overfeed yet still be lacking in nitrogen?