A plant terrarium is a mini-ecosystem that creates its own atmosphere and needs little from the outside except light. Moisture that condenses on the glass runs down to remoisten the soil. The glass protects the plants from insects and diseases, as well as the dry air associated with many homes.
A London physician accidentally invented the first terrarium in the early 1800s. Dr. Nathaniel Ward placed a cocoon in a covered jar so that he could observe the emergence of a sphinx moth. In time, several plants sprang up from soil in the bottom of the jar, including a thriving fern. Ward had unsuccessfully tried to grow ferns in his yard and blamed the failure on polluted air from city smokestacks. After his discovery, he constructed several fern containers, later called Wardian cases. These early terrariums quickly became popular, especially with the affluent, who had large, ornate cases made to display houseplants, miniature gardens, and woodland scenes.
Best Terrarium Plants
Most houseplants are tropical and make ideal residents for a terrarium. Miniature ferns, peperomias, African violets, and some orchids are all good candidates. Many woodland plants and mosses are right at home under glass.
How to Make a Terrarium
You can use almost any clear glass container, such as an aquarium or big fish bowl, to construct a terrarium.
- Start by covering the bottom of the container with a one-inch layer of pebbles or crushed stone.
- Add chunks of charcoal to the stone, or cover it with a thick, 1/8-inch-deep layer of crushed charcoal to absorb odors.
- Next, add two to three inches of damp potting soil and firmly tamp.
- The soil can be molded into hills and valleys to add interest; add rocks and small logs for a natural-looking setting.
- Once planted, cover the top of the terrarium with a pane of glass.
- If the sides fog up from excess humidity, leave the top open a crack so that some of the moisture evaporates from the container.
A sealed terrarium will go for months, even years, without needing water. Keep your terrarium out of direct sunlight to avoid overheating; fluorescent lighting is ideal.
You will want to display your terrarium where it is sure to be noticed, because it may just give the room, as well as your plants, a little atmosphere.