Wanting to do a small outdoor enclosure in our "yard" (like 5 by 8 feet maybe) but I'm not sure what to use as substrate? Because what's out there now is dirt/soil but I think it has fertilizers in it and I'm not sure if that's okay for my tort. I don't want to plant grass, I've tried twice now and failed >_< Could I use pebbles/small rocks? Coconut coir? Play sand? Right now for main indoor enclosure I use the expandable coconut fiber eco earth stuff, should I use that? Thanks for any feedback!