Not sure what’s wrong

I think its iron/sulfur deficiency..google up cannabis leaf deficiency they are 15 different.. 1 over watering 2 under watering 3 over nutrients-i.e.nut's burn 4 +/-nitrogen 5 +/- phosphate 6+/- potassium 7 +/-cal/magnesium 8 +/-sulfur/ iron 9 hi temperature 10 insects 11..12..13..14 .15. Would be the ""-""off numbers #4..#5..#6..#7..#8.... I would say its #8 good luck...if its close to harvest dont bother just ride it out... Flush / restart with quarter dose is remedy for just about all diagnostic it really comes down to how early we treat it...Have fun Stay safe Growers❤️💯💯

Google leaf septoria... Everyone is overlooking this issue but it's more common than anything else..

If you're not giving any nutrients, then you have major deficiencies. Any time release fertz in the soil is likely gone. Get a nice bloom nute with low N, high P and K (N-P-K on the nutrient container), and also some calmag.

Hey your girls do look good, but looks like they aren’t getting enough cal/mag. If you are getting to the end of the cycle, the girl could be getting ready to die. She could be coming to the end of her life cycle. Happy growing