I use general hydro "floranova", a decent newer one-part for my hydro and have been told by the guys at the shop it works well in soil also, I use my left-overs on my tomato plants and they are pretty healthy.
General Hydroponics are excellent, indeed the industry standard.
they are chemicals. If you mix them in organic soil you'll kill a lot of the beneficial flora and fauna (microbes, mycorrhizae, nematodes) in your organic soil.
If you're using Fox Farms potting soil, you paid premium prices for soil with those organic goodies. If you use chem's you could instead have used cheap unamended soil at about 1/2 price.
I recommend sticking with organics.
I also use kool-bloom with my flora-nova but you don't need very much at all, flora-nova has a lot of the stuff cool bloom has in it allready. As was said, GH stuff is chemicals but flora-nova has more natural ingredients in it. It has the molasses and such. If you do go with it be warned, it is very, very concentrated, just pick up a bottle of it and a bottle of pure blend, you can feel the difference, so be careful.