Garden Under Glass: Grow Houseplants in a Terrarium

Terrariums are miniature gardens enclosed in glass or clear plastic.


They were very popular during the Victorian Era in Britain and in America. Glass Carboys, or bottle gardens were very popular then. These were longneck bottles in which small plants were planted and allowed to grow. During the 1960s and 1970s terrariums started to become popular again but instead of using bottles, fish tanks and other containers were used.

A terrarium has two basic features:

  1. It surrounds plants completely or almost completely with glass or plastic.
  2. Access to outside air is either strictly limited or non-existent.

Terrariums require little care if kept sealed. The moisture needed by plants is given off through the leaves by the process of transpiration. The moisture condenses on the glass walls and runs down to moisten the soil. A well constructed terrarium needs only light and warmth to flourish.

Choosing a Container

Any clear or tinted glass container can be used if it will admit light inside and allow plants to be seen. Fish tanks or bowls, brandy snifters, pickle jars or large bottles will do. If the container does not have a lid, a sheet of clear plastic or glass makes a suitable cover as long as it fits tight. Make sure the container is clean and dry before beginning to plant to avoid any bacteria or mold.

Preparing to Plant

The bottom of your terrarium must have the ability to drain excess water so that your plants will not rot. Spread a handful of crushed charcoal on the bottom to keep the terrarium fresh. Cover this with about 1 to 1 1/2″ of pebbles or gravel. Next apply 3 to 6 inches of a good porous sterile potting soil that is slightly damp but not wet. You can construct hills and valleys in the soil and add rocks, wood, or other landscape material that will please the eye.

Dig small holes to insert plants but be sure none touch the sides of the container or they will turn brown.

A small amount of water may be needed at first. Let it trickle down the sides of the container until the soil is moist.

Avoid clutter in your terrarium. A few well-placed plants are better than over crowded jungles. Space should be left to allow room for growth and to provide air circulation.

Types of Plants to Use

Plants suitable for terrariums are any tropical plant. African violets, Zebra plant, Norfolk Island Pine, Parlor Palm, Peperomia, Fittonia, Baby’s tears, Prayer plant, Sensitive Plant, Miniature Gloxinia, snake plant, asparagus fern, any other small fern and any moss are suitable.

Care of Your Terrarium

After planting, place the terrarium in a shaded area for a few days and watch carefully. If water condenses heavily, remove the lid for several days so excess moisture can evaporate. If plants wilt and no condensation forms, add a small amount of water. After a week, place the terrarium in a well lit (but not in direct sun) area. Glass magnifies the sun’s rays and the temperature can build up to dangerous levels.

Overwatering is the most common mistake made by terrarium keepers. If sealed, your terrarium should make enough water on its own. Do not fertilize, you don’t want your plants to get too large too fast. Rate of growth is dependent upon the amount of light received. If algae begin to grow on the container, it is in too much light.

When plants get too large they must be pruned or removed. Take time every month to remove dead leaves. Other than that, your inside garden will take care of itself.