if im growing inside a greenhouse, what should I add to the dark natural soil for nutrients? are there nutrients already in the natural soil if its dark with grass vegetation and worms?
if you want to know for sure, get a soil test kit. If other stuff is growing in it, chances are it has SOME nutrients. You can mix in some dolomite and some general purpose fert and go from there if you like. Personally, when I grow in soil, I rather container the plants that way I can test and adjust as necessary for the different grow rates of the plants.
