A terrarium is a closed glass container, and inside is a self-sustained Eco-system, a miniature garden that takes care of itself.
Tropical plants such as mosses, ferns and orchids are perfect for a terrarium.
Besides plants and a glass container, a small terrarium needs a handful of pebbles, charcoal (Aquarium supplies), sphagnum moss, and potting mix. Shells, crystals, miniature statues add a whimsical touch to the finished landscape.
Here is how I set up my terrarium:
first layer pebbles, second layer charcoal, third layer moist potting mix.
I added the plants surrounding them with moistened sphagnum moss, and a few sea shells finish the display.