While gardening has long been a favorite leisure activity for adults, parents may be looking for ways to interest their children in this hobby, as well. With traditional gardening activities taking a back seat for the cold weather season, building a terrarium is a great way to engage youth in this popular activity.

 

You may remember the popular glass or plastic spheres or orbs, often enveloped in a macrame hanger. Today’s terrariums are more modern and actually increase the visual presence of the plants within them.

 

The concept of the terrarium was developed in the early 1800s when Dr. Nathaniel B. Ward, an English physician with a passion for botany and entomology, discovered he could germinate spores of a desirable fern within a closed glass jar. He developed what is known as the Wardian case, a glass-topped box resembling a miniature greenhouse that was used to transport plants collected in distant countries back to the British Isles. Within this closure he could grow plants in conditions that were almost like those of their natural environment. Because the plants inside the container were decorative, the idea was soon adapted to home interior decorating.

 

A terrarium is simply a garden in an enclosed glass or plastic container. They are a great way to grow a collection of small plants. You need just a few supplies to get started, including a clear glass or plastic container, potting medium, plants, water and a bright window. The container doesn’t have to have a top because it can easily be covered with clear plastic food wrap.

 

It’s best to use potting soil instead of garden soil since garden soil is heavy and doesn’t provide adequate aeration and water movement. Stay away from using rocks, charcoal or sand for drainage. Potting medium is like a sponge and will hold the water until it becomes completely saturated. Using only potting medium will help avoid root rot.

 

Choose plants that are naturally dwarf, slow growing, tolerant of high humidity and tolerant to low to medium levels of light. Mix it up by choosing plants with varying colors and textures to add visual interest. Avoid cactus and other succulents as the environment inside the terrarium is too humid. A dish garden is a better choice for succulents.

 

When adding the potting medium, add about ¼ inch for every inch width of the container, but there’s no need to exceed 3 inches deep unless creating a berm. Varying the depth of the potting medium adds visual interest. Natural rocks and stone can be added to complete the plantscape.

 

When it comes time to plant, consider where the terrarium will be placed and how it will be viewed. It should be near a bright window, but not in direct sunlight. If it can be seen from all sides, plant the taller, vertical plants toward the middle, with shorter, rounded plants around the edges. If the terrarium will be viewed from just one side, the taller plants should be placed in the back and shorter plants in the front.

 

Once planted, add small amounts of water from a spray bottle set to a coarse stream to rinse off the plants and the terrarium walls. Avoid getting the plants too wet since they won’t dry quickly in their environment. Keep the potting medium moist, but not saturated and cover with the container’s lid or clear, colorless plastic food wrap. The lid may need to be vented on occasion to reduce humidity.

 

To keep the plants from outgrowing the terrarium, use fertilizer labeled for houseplants at half the recommended rate and frequency.

 

For a list of plants appropriate for the terrarium, along with additional information, see Oklahoma State University Extension’s fact sheet on terrariums.