Live Plants In Terrarium

I am setting up a tank for a baby female bp, and to help hold humidity and for the looks. I want to add a pothos, but I don't know what I should plant it in. I do not know if dirt is harmful, carries mites, or if there is a reptile substrate good for growing plants. Thanks.

I've got a tendril of philodendron that Marble loves. She crawls all around it and smells every leaf. I just have it sitting in a cup of water, no dirt or anything, and it seems to do okay. If it dies, I'll just cut another string from the main plant and replace it.

You could do pothos (Devils ivy) I would wash the plant and roots and repot in soil that has no fertilizer