Well, I don't really have a set time when I stop giving N. I just use veg nutes during veg and then switch to bloom nutes when flipping to 12/12. Makes it easy. It has been my experience that yellowing due to N deficiency starts around 5-6 week of flowering and continues to the end (indica dominant), so yours does sound a little early.

My bloom nutes do have some N in it so I don't think you should cut N out completely during flowering.
Perp Reviewed by Perp on . lack of nitrogen, when to start giving more p hi guys, im on the 4th week of my second grow... got 6 females out of 10 so im pretty stoked! the plants are doing alright however they are starting to get yellow not so healthy leaves at the bottom.... i know you are supposed to give the plants more Nitrogen during vegetative growth but when is it time to start cutting that down? because i started giving the plants a supplement of P + K (P-8 K-4) 2 weeks into the flowering and thats when the leaves started to get yellow so a couple days ago Rating: 5