Don't buy vermiculite for anything. It's a waste of money. You can use either perlite or hydroton in hydro. All these materials do is provide stability for a plant, not nutrients. Happy Frog soil is good if you want to stick with soil. Hydry grows require a fert that is made for hydro. You grow shop has many to choose from. Dynagro is a good brand in my opinion. If I were you, I stick with soil.