Sorry, missed the nutes at the bottom. While in vegetative growth, about the first 5-6 weeks, you need nutrients that are higher in nitrogen, something like a 10-5-5. What you are using would be better for flowering.
Judging by the way your leaves are drooping and how they are turning up along the edges they look to be over fed. Are you seeing any browning along the tips or edges of the leaves? I'd suggest you flush them with plain pHed water, 3x the size of your pots. So if your pots are 1 gallon, flush with 3 gallons of water.
MG soil is not the best for growing weed. Does it contain any slow release nutrients?