Using Miracle Gro
Not a noob question. The organic potting mixture is a good nutrient, but very messy. I tried it in a small tank to find out how it would work and it really didn't very well.
It could work if you layed down no more than in inch on the bottom and then topped it with a fairly thick layer of a somewhat finer substrate. I would do all the planting prior to filling the tank if at all possible and filling is very tricky. A mistake during the filling process and you'll have floating debris in the water.
I use the potting mixture in plastic pots topped with standard aquarium pea gravel. The potting soil will nourish the plant for several months. Combine the mixture with a good liquid with the trace elements and the plants do very well.
"Aquarium (Water Building) Keeper"