leaves yellowing before harvest

Hi all.

I've got 2 white widow have been flowering for 6 weeks now. hairs are half white/brown. Plants getting quite yellow in places. I've read that should happen at the end of flowering, and NOT to try correct with more Nitrogen. Should i be upping my nutes? or is 6 weeks kinda normal

thanks

ps. i know i have heat issues and spider mite issues that's being sorted. Its been a good learning curve

Its natural for the plant to pull the nitrogent it needs from its fan leafs during early flowring.
And late in flowering they will begin to die off as the plant is reaching the end of its life