How to Create a Terrarium Garden

You Will Need:

1 large glass apothecary jar with a removable lid (make sure your hand will fit inside)
Pea gravel or small decorative pebbles
Activated charcoal (available at garden centers and pet stores)
Sphagnum moss
Terrarium soil or good quality potting soil that has been pasteurized to remove harmful organisms (never use garden dirt)
3, 5 or 7 small plants, depending on container size (see #6 for information on plant selection)
Optional: small decorative rock, shell or driftwood to add visual interest

Instructions:

  1. Apothecary jar terrariums are popular; but you can use any watertight glass container with a secure but removable lid, such as a Mason jar, fish bowl, aquarium tank, brandy snifter, decorative bowl, etc. If the container does not have a lid, a hardware store can cut a piece of glass to fit. Be sure to add 1/2 inch (small containers) to 1 inch (large containers) to the container dimensions so the “lid” will protrude slightly past the container’s edge when set in place.
  2. Begin to build the layered base by placing a 1-inch drainage layer of pea gravel or decorative pebbles on the bottom of the container.
  3. Using a large spoon, sprinkle a thin layer of activated charcoal over the gravel.
  4. Add a 1-inch layer of sphagnum moss to prevent the soil from infiltrating the drainage layer. Tamp down gently to compress the moss.
  5. Add a 1- to 3-inch layer of soil, depending on the height of the container.
  6. Plant selection: Choose small plants with similar water and light requirements that will thrive in high humidity. For best visual impact, select plants of varying height, shape, color and texture that complement each other. An odd number of plants will create a more pleasing arrangement.
    Good terrarium plants: African Violet, Basil, Caladium, English Ivy, small ferns, Heartleaf Philodendron, mosses, Parsley, Pothos, Primrose, Spider Plant, Viola. Avoid cacti and succulents which will fail in the moist environment inside a closed terrarium.
  7. Decide where to place each plant. Remove plants from their pots. Lightly place plants on top of the soil, moving them around until you determine the best arrangement. Allow sufficient space between plants to promote healthy growth. Plants should not touch the walls of the container. If the terrarium will be visible from all sides, place tall plants in the middle and surround with smaller plants. If the terrarium will be viewed from one side, place tall plants in the back with smaller plants up front.
  8. Using a spoon or your fingers, dig a shallow hole for each plant. Place each plant, firming the soil around its stem. Press soil down lightly to hold each plant in place.
  9. After planting is complete, you may wish to add a decorative rock, shell, piece of driftwood or other object to add visual interest.
  10. Water sparingly with a mister or thin-spouted watering can. Terrariums create a self-sufficient environment. Plants transpire through their leaves, releasing moisture that condenses on the sides of the terrarium and trickles down into the soil, maintaining a sufficiently moist growing environment. Terrariums require only minimal watering every 2 to 6 weeks.
    Watering tips: Water when no condensation appears on the glass. Water a tablespoon at a time over several days until condensation reappears. If large water drops form on the glass, too much moisture is accumulating inside the terrarium which can cause fungus or mold. Leave the lid open for a day or two to allow excess moisture to evaporate.
  11. After watering, put the lid on the terrarium and place it where it will receive indirect light.

Note: For large terrariums, increase pebble depth to 3 inches and soil depth to 3 to 6 inches, depending on container height. You will also need to increase the number of plants used. Large terrariums can be “landscaped” to add visual interest by adjusting soil depth to create hills, valleys and terraces.