Mangelerscheinung

Phosphorous deficiency. Wood ash can be highly alkaline and is not the best idea..........guano is a better option, but try smaller doses at first because it is usually very concentrated and there is a very fine line between enough and waaaaay too much.

Looks like the older fan leaves.It will be lacking nutriton.You need a PK booster which will improve the size and quality of the flower.They sue a lot more P phosphorus and K potassium in flowering especially mid flower.Guano is around 14% P and Hard Wood Ash is around 30% which is high but its organic.Any hard wood ash will do and bat guano improves smell and taste.Without the bat the taste is flat as the old saying goes.Guanokalong sell both.Google PK use during flowering.