How to Make Your Own Terrarium

Creating a garden under glass gives kids the chance to fashion a lush miniature indoor garden. The terrarium can be the perfect place to unleash your imagination. The garden can have a theme and decorative elements — a few small stones can define a planting bed or create a walkway, and small sculptures or found objects provide the finishing touches.

Terrariums come in two types: open and closed. Open terrariums are easier to establish since air flow and evaporation are continuous, and there's less likelihood of disease; depending on the size of the opening, however, regular watering is necessary. Closed terrariums are essentially ecosystems. Regular watering isn't necessary; water evaporates onto the inside of the glass and "rains" back down on the garden. Closed systems have to be monitored closely for the first few weeks to make sure no diseases crop up in the high humidity; after a few weeks, there's less need to be vigilant.

Start by making a sketch of how you want your garden to look before you decide on a container or do any planting.

Materials Needed:

• clear glass or plastic container (kitchen canister, jar, fishbowl or tank, etc., and lid), clean and dry
• pea gravel or polished rocks
• activated charcoal
• sphagnum moss

• potting soil (fresh bag to make sure it's sterile)
• small, slow-growing plants that tolerate low light and have similar water needs (be sure the plants are healthy and showing no signs of disease)
• spoon, long-handled (if container has a small opening)

Create the Garden Bed

1. Add a 1- to 2-inch layer of pebbles to the bottom of the container for drainage (Image 1).

2. Add a 1-1/2-inch layer of activated charcoal over the pebbles (Image 2).

3. Add a 1-1/2-inch layer of sphagnum moss over the charcoal. This will help prevent soil from moving down between the pebbles.

4. Pre-moisten the potting soil till damp but not soggy, and add three to four inches to the bottom of the container. The amount you add will depend on the size of the container and the type and size of plants that you want to grow (Image 3).

Plant Your Terrarium

Remove plants from their pots (Image 1). Remove excess soil from around their roots, and cut away pot-bound roots. If a plant is too big for its place in the container — either in size or root mass — divide the plant at its roots, if necessary, to fit the size and scale of the container. Create a planting hole in the soil (Image 2) and place each plant where the leaves won't touch the glass; firm the soil around the base of each plant.

Decorate Your Terrarium

Finish off your miniature garden with stones and decorative pieces as desired (Images 1, 2 and 3).

Lightly spray the foliage and inside of the glass to remove any soil particles.

Place in a bright spot indoors but out of direct sun, and leave the top on for a day or so until the leaves and glass dry. If the soil feels soggy, remove the top of the terrarium and let the excess moisture evaporate. Then put the lid back on the container.