I read somewhere that Standard Miracle-Gro is okay for flowering, but for veg you want to go with Miracle-Gro tomato food because of the higher N levels. I have hear bad stories about chemical ferts and have had my plants burn the first time growing because of premixed chem ferts in the potting soil (Pirate is right about them). But then again, it may workout fine for you. Try using 1/3-1/2 of the recomended mixture of fertilizer before using the fully recomended dose