Which General Hydroponics are you talking about? Any of them can be used for hydro or soil. But I do know that the GH Pure Blend Pro has one for Hydro and one for soil. But each will work for the other, just not as well. So just read the lables. If it does not say it is for one or the other, then WALLA, you are set. If you are growing in soil, and it is GH Organic Nuts, you my want to add some Sub Culture. Your Hydroponics store will have it.