How to care for dirt?

[Yoda]

I have wondered what is the best way to treat soil for my tomato frog. I use plantation soil and coconut husk, because I think I should change it every once in a while. It also becomes dry several days later after heat and air exposure and do I just take it and soak it again. I get my soil from the pet shop so how should I care for it. I don't want it to get musty or not treating it properly. Please give me some handy info so I can help my frog.