J_Kushanswered grow question 1y ago Looks like you messed up the soil pH with fertilizer. It looks overly acidic, which means nutrient selection mechanisms won't work anymore, too much fertilizer seeps in and burns your leaves.
You can either flush it out or just water for the next 2 weeks and wait for it to regulate itself a bit.
It's best to remove the affected leaves. Due to the damage, a fungus can invade, and there's no photosynthesis happening there anyway.
I wouldn't fertilize at all or very little during the last 4 weeks of flowering, as they mobilize nutrients from old leaf mass and don't need that much through the roots.
Wishing you a big harvest. I also have some Foster seeds lying around. I'm curious!