If you use any nutrients in MG soil you run a risk of harming your plants. Next round do your self a favor and toss the Miracle Grow, use proper soil where you can feed the plants the food they need to grow big?
Miracle grow is like feeding your plants junk food all the time. NOT good for growing plants like this.
Sorry, but if you can transplant them into good soil you may be all right.
MG is not good for this plant, it can't follow the cycle of life the plant goes through and you can't feed it either.
Good luck and do your best to keep the Ph in check.
If you go cheap you grow cheap. - Me