fan leaves yellowing

Hey smell an all leaves dried an yellow week 6 of flower plzz help out

Hello rollitup users, I was wondering when I should start my final flush before harvest? My fan leaves are starting to yellow and I'm still giving her nutrients, I'm in the 8th week of flower and I'm growing in coco so I would like to flush for about a week. I would say about 70-80% of pistils...