That's cool you have a terrarium!
I made a small one using a big pickle jar, and it's working great so far.
I just have dirt/fertilizer at the bottom, then rocks and moss.
It looks like a little piece of some pretty place.
When I open it though...it still smells like pickles.
Oh, I put seashells at the bottom before adding the dirt/fertilizer.
"Life is an adventure full of beautiful things, and a treasure worth more than gold."