they should be okay. just use a natural soil mixture that has worm castings and stuff, that way you wont have to fertilize much; also, don't fertilize every day. once or twice a week is plenty, also, light is a big factor in stretching. try not to flood the plant either, instead, just make sure the soil is thoroughly moist. if you dont want to get different soil, (you dont have to), just mix the fertilizer at about 1/4 strength, then about a week later you can up the dose. its okay to put less fertilizer then what the package says.
on a different note, i wouldnt use miracle grow. just personally though. general hydroponics has this complete organics box, everything you will need.