Colour.

I'm thinking you're relying too much on your super soil and it's run out of nutrients for your plant. This is a classic phosphorus deficiency brought about by a couple of things: for one, your pH is much too high - it needs to get down to 6.0-6.4 and the fact that your soil is probably out of food. You need to both drop your pH and start feeding some good NPK bloom nutes along with a good PK booster... If you want to rely only on organic remedies, the addition of some bonemeal is a good source for phosphorus - but she's also going to be needing a lot of potassium in flower... Langbeinite is super for this but doesn't dissolve very easily so what I've done in the past is to use a tablespoon of the granules as a top dress once a month... Good luck...