You are going to want a different fertilizer when your plants start flowering. That food has a lot of Nitrogen in it (the first number), which is good for the vegitative phase but not the flowering phase. You'll want a fert with a small amount of N and much larger amounts of P & K. You could also get a Grow fert from the hydro/grow store that was designed for MJ, instead of using the Miracle Grow. Most brands have 'Grow', 'Bloom', and 'Micronutrient' fertilizers, with different ingredients or amounts of ingredients in each formula designed to be used in specific stages of your plant's growth.