Hi!
I don't know if one could safely use co2 apply but you can set a planted tank also without co2 and fertilizers. Here was some old thread about planted tanks, take a look via search if you can find it (I'm on phone and search doesn't work here). It just takes a bit of time and you should choose such plants that are not into heavy lightning. In my tanks vallisneria, java fern and moss (other mosses too), anubias and top plants have been successful. And some long flowing plants which I can't remember in English. I have either bare bottoms or sand and in one tank tried dirt + sand and I've put clay under the root plants as a fertilizer.
