Miracle Grow is not formulated for use with Cannabis! It is done so on purpose by Scotts......
Try Jack's Classic citrus or plain jack's classic at 1/4 tsp per gallon, every watering.
Basic thing is your not feeding enough.....N def and many others too.
If your in Miracle grow soil - the timed release shit....your going to have nothing but problems....
I suggest you read this book.....It'll help.
I'll be sure to check it out. I switched my soil to fox farms ocean forest mix for now