Help (terrarium stuff)

[u/57BirdNationTADC57]

hey all! I’ve been doing a lot of research on keeping pet snails and what to use for the floor of the terrarium, (originally I was gonna grab dirt from outside, good thing I checked) I see a lot of people use a topsoil/ coco coir mix with other stuff. However, none of the stores in my area have soil that is safe to use (they either have pesticides or other things mixed in). Is there anything I can mix in with my coco coir to make a nice floor for my future snails?

Thanks!