In about week 5 of flower and some of the lower leaves on some plants are fading. Root organics 707 amended with chicken poop, fish poop, worm castings, and oyster shell in 5 gallon fabric pots. Plants get fed Recharge and Mammoth P every week. I’m thinking they are root bound?
Yellowing leaves at this point seems ok. I’ve grown in 5 gal fabric pots and it’s what I’d call the just in time method. They look good for five weeks of flower. Your mix sounds good too but you didn’t mention additional feedings. They’ll need some form of P&K and probably calcium/magnesium soon. And please do not transplant in flower.
Couple things. Those plants don’t look bad. The back right is showing some purple petioles but that shit happens a lot. It could be a stress or a magnesium or phosphorous deficiency. Try a little epsom salts in your next feeding. Your fan leaves are going to start discoloring and dying off as the plant ages and consumes the nutrients in them. Also I doubt you are root bound. It is a five gallon and you are only five weeks into flower. Plus it is a fabric pot and will tend more toward a root ball rather than circle the container. Especially if you are using recharge. I think you are ok.