Wash the glass container in hot, soapy water. Rinse and dry completely.
Create a one-inch (2.5-centimeter) layer of stones on the bottom of the jar.
Add a half-inch (1.3-centimeter) of charcoal.
Spoon in a two- to three-inch (5.1- to 7.6-centimeter) layer of potting soil. (Pile soil higher on one side to make plants visible from a side view.) Dig small holes for the roots.
Take plants out of their pots, remove extra soil from the roots, and trim damaged leaves. While the roots are still moist, place the plants in the holes and pat soil over the roots. Place taller plants in the back. Dampen the soil. Do not overwater.
Decorate with pretty rocks, animal figurines, or a garden gnome. Place in indirect sunlight. Add water when your terrarium gets dry.
TIPS
Pick the right plants. Almost any houseplant will grow inside a terrarium. For best results, use plants that need about the same amount of water and sunlight, such as:
Moss and lichens
Miniature orchids
Baby tears
Begonias
Miniature ferns
Hepaticas
Spider plants
Wintergreens
Gloxinias
Small palms
African violets
Coleuses
If your terrarium has a small opening, use chopsticks to position your plants.
Prune fast-growing plants so they don't outgrow the terrarium.