Before you decide on any soil you need to know what is going into your terrarium – the plants – not the fun decorations.
Obviously, a succulent or cactus open terrarium will require far different soil than a lush, leafy, flowering closed terrarium. (That should be obvious, but forgive me, there are some who just dive in without thinking and wonder why their project was doomed from the start.)
- glass container
- rocks or pebbles for the very bottom level so your plants never “sit” in water
- a layer of charcoal
- appropriate soil mixture for the type of plant you plan to grow
- perhaps a layer of moss for lush plants or sand or tiny pebbles for succulents
- then whatever decorations you plan on adding (that is entirely your choice)
I found a really good soil mixture recipe at Martha Stewart’s Living site, you might want to check that out at some point.
But no matter what you plan on planting in your new terrarium – begin with a plan, the right soil for your plants – and then just go have fun with it all.