Rust spots / crispy fan leaves?

Hey friend So i think you're seeing the progression of a phosphorus deficiency possibly accompanied by a calcium deficiency. I love doing organic grows...but unless you're doing a living soil blend with a tremendous amount of nutrients and living organisms built in to last a long grow you really need to be feeding some nutrients. Even with living soil you usually will need to top dress occasionally. Look into adding some bloom and micro type nutrients and watch for the problem to stop spreading. Double check your ph is in a good range too. Fortunately your able to fix pretty early in flowering so some young leaves should still replace the damaged ones. Keep growing forward. ✌️