There's one thing I don't understand....
the color of the leaves is very dark and I hope it's just the camera making them look darker.
Such a dark color is usually a sign of a lot of nitrogen, and looking at the fertilization you're giving, it doesn't seem possible unless you've used some pre-fertilized soil.
In that case, if the leaves are actually lighter than they appear, you should increase the fertilization a bit to the larger amount.
I went to check the strain and it seems to be naturally a bit darker than usual.