What kind of medium are you using? Just potting soil? If so, look to see if the soil has time release nutrients in it already. And also, Miracle Grow isnt the best nutrients for cannabis plants. I'm on my first grow and I used a water Soluable Miracle Grow Mix. I used these nutrients every other watering. After a few waterings with the nutes, my plants got nute burn. I would suggest not using miracle grow and look up some other nutes that work good. But if you insist on using miracle grow nutes, use it at a quarter of strength it recommends. I would use it every third watering day. You should also research different kinds of nutes. They make nutes for plants in their vegatative state and nutes for plants in their flowering state. They differ by the NPK amounts. N is for Nitrogen, P is for Phosphorous, and K is for Potassium. A plant needs different amount of these compounds for the different stages of life they are in. I hoped i helped you.
Happy growing and Peace.