This means that Miracle Grow soil already ferts in it, and that is exactly why I do not use it. I like to control exactly what is going into my plants to the closest extent possible.
Miracle Gro products a very, very average for mj plants. They simply do not contain the micro nutrients that mj needs to thrive.
My favorite brand of potting soil is called Premier Pro Mix, already comes with added perlite and vermiculite and all the non chemical goodies you want in soil. 'Chemical goodies' should be left to fertilizing the plants. In that case Fox Farms, General Hydroponics, and Dutch master are the best brand names for mj ferts.
Whats up Ptbo Stonerz. I myself have used MG soil with nice results in the past. Check out my thread in the grow journal section. If you use MG soil you have to be very careful when adding nutes. I mean real careful.
You want to be able to provide your plants with lots of N and not much P during veg, the opposite of that when they're in flowering, Too much of one locks out the other, meaning an overdose of one while leaving the plant starving for the other.
I recommend quality potting soil will all kinds of goodies such as worm castings, bat/bird guano, seaweed/kelp, and hydrated lime.
And to go with that, organic nutrients which you will need to add in 8--10 weeks.
P.s. don't add chem. nutes to organic soil, it kills all the good stuff.