One of the most important things to consider when making a terrarium is which plants to include in your miniature garden. The most important thing to consider when selecting plants is to look for a species that won't outgrow your container, so smaller plants are preferable.
You also want to consider whether your container will be open or closed. If you plan on using a closed container, the environment will become humid. Choose a plant that tolerates humidity well. If your container will be open, humidity won't be as much of an issue so you can include drier plants in your options as well.
Another important factor in choosing what to plant is sunlight. Most terrariums are kept inside, so you want to choose plants that thrive in low to medium light.
Once you've considered size, humidity, and sunlight requirements, consider the terrarium as a whole. All the plants in your terrarium should have similar growing requirements since they will be living very close to each other. You don't want one plant to require lots of water while its neighbor needs dry soil.
Also consider how the plants will look aesthetically next to each other. A good rule of thumb for designing terrariums is to vary the size, color, and texture of the plants to create interest. The photo above is a great example of variety in a terrarium. The colors and shapes of each plant complement each other and make the terrarium as a whole more interesting.
Here are a few plants that do well in terrariums:
Most carnivorous plants, including Venus Fly Traps.
Cotyledon orbiculata, commonly known as Pig's Ear.
Helxine soleirolii, aka Baby's Tears or Mind Your Own Business Plant.
One of my favorites, Hoya Bella, otherwise known as Miniature Wax Plant.
Selaginella, known as Spike Moss.
Fittonia, the "Nerve Plant"
Echeveria, a flowering succulent.
All of these plants, and more, can be purchased in our online store here. There are hundreds of other great terrarium plants out there. Take a trip to your local nursery and see what inspires you!