Terrariums Terrariums

A terrarium is a beautiful little self-contained, self-sustaining universe. The plants soak up moisture from the soil, then give the moisture back into the air through a process called transpiration. The water condenses on the glass walls of the terrarium and runs down to the soil.If you've ever had the pleasure of wandering into a greenhouse in the middle of winter, you know how being around healthy, living plants can infuse you with a feeling of relaxation, and can even convince you that spring will indeed return again.

An enclosed terrarium can add that greenhouse-like feeling to a room, without requiring much care. If you include lizards, your little greenhouse will technically be called a "reptarium," and if you include a dish of standing water, it is technically a "vivarium." Of course you'll check with the pet store to make sure the plants will be compatible with the creatures you include.

Terrariums are also good choices for those people who live with certain cats, the ones who love nothing more than to chew up greenery. Chances are, if you've tried having both cats and houseplants, you know that buying a plant often just entails making an investment in Kitty's hobby of ingesting leafy greens. At best, you end up with a shredded stalk in a pot, and at worst, you end up poisoning Kitty, as many common houseplants are indeed quite dangerous. Because a terrarium is enclosed, the plants within will be safe from Kitty's attentions.

The Water Cycle

The principle behind the terrarium isn't very complicated; it's really the same principle that the whole earth runs on. The rain falls, then evaporates into the air, gathers in the clouds, and falls again. It's the beautiful cycle of nature. And you don't have to do anything to keep it running except mist it occasionally and make sure you don't pump carbon monoxide fumes into it.

Terrarium History

While there are terrariums to fit into any style of home décor, they date to the early 1800s, a time when people were fascinated with the workings of the natural world, and were eager to find innovative ways of bringing the outdoors inside.

The discovery of the terrarium was actually a happy accident caused by pollution, of all things. In 1827 a London doctor and amateur botanist, Nathaniel Ward, found that his fern garden was being choked off by the heavy pollution of industrial-age London. Simultaneously, he was busy keeping caterpillar cocoons for study in glass jars, and he noticed a tiny fern growing quite happily in one of the jars. It didn't take him long to figure out that he could grow his garden ferns in jars, protecting them from the harsh realities of gritty urban life.

The terrarium's popularity quickly spread, in part because its invention was made at a time when many English were also becoming interested in exploration and discovery. The jars were ideal for bringing home exotic tropical plants, and then for keeping them alive once they were in the cold, inhospitable climate of Mother England.

Choosing Plants

When looking for what plants to put in your terrarium, first choose plants that love moisture and don't grow very large. Then take into account their requirements for light. Ferns, lichens and mosses are good choices for a spot with poor natural light, as are Swedish ivy, bird's nest sansevieriea, and maidenhead spleenwort. There are many more plants that will thrive in medium light, among them Irish moss, Tahitian bridal veil, heart-leaved philodendron, pitcher plant, and butterwort.

TIP: Pur expert gardening advisor, Karen Thurber reccomends, "Spend time researching the plants you want to grow in your terrarium. This step is very important and should not be overlooked. Choose plants with similar environmental requirements. The closed environment of the terrarium means that all the plants need to have the same humidity, light and soil requirements. Carefully choosing your plants can make an enormous difference in the success of your terrarium."

It's recommended that you never place your terrarium in direct sun, doing so will cause it to over heat. However some plants which enjoy more than just medium light include hen and chicks, jade plants, asparagus ferns, and Venus fly traps.

TIP: Karen adds, "Terrariums that have plants with higher light requirements can be located near a window with direct sun or supplemented with artificial light."

For color and interest, consider adding flowering plants, such as African violets, roses and geraniums. Once you get the hang of which plants will thrive in a terrarium environment, your imagination is your only limiting factor: you can make a little woodland scene with miniature pine cones and a tiny mirror for a lake, and you could even plant tiny dolls into the forest. Once you add things other than plants, keep an eye on them to make sure they don't rot in the moist environment.

TIP: Karen advises, "Some of the plants you may want to include in your terrarium may not thrive in a closed environment. This should not deter you. Leaving the lid off and making it an open terrarium will maintain a lower humidity, widening the range of plants you can use in your terrarium."

Creating Your Terrarium

Start by lining the bottom of the terrarium with a drainage layer, which will prevent the roots from rotting. You can make this with a little crushed charcoal covered with a thin layer of pebbles or gravel. On top of this, sprinkle a layer of activated charcoal--found in pet stores, as it's used in aquariums--to help keep the air clean. Next, add a thin cover of sphagnum moss, which will prevent the soil from sifting down to the drainage layer.

Finally, add a layer of soil. In many gardening shops you'll find a special terrarium mix, consisting of potting soil with sand added to it. If you want mix this yourself, add 1 part coarse builders' sand 1 one part leaf mold to 2 parts of your usual mix. Never use beach sand in any potting mix, as it has other elements that will not be good for your plants.

When adding the soil layer, keep in mind that you want to vary your "landscape" by creating hills and terraces. If your terrarium is going to be home to any live animals, such as lizards, tarantulas, or other wildlife, make sure you include a water source, by embedding a shallow dish into the soil and keeping it filled with fresh water. You should also consult with a knowledgeable pet store clerk or a veterinarian to make sure the creature will have what it needs. If you're not worried about keeping a live creature hydrated, you can also create the look of fresh water by embedding a mirror into the soil and planting small ferns around the edge.


When establishing the actual plants and deciding where to place them, think about how the terrarium will be viewed. If all sides can be seen, plant the largest plants in the center; if it will be primarily seen from the front, plant the largest plants in the rear, with shorter plants in the foreground.

Plant the plants just as you would outdoors, by digging a hole and then firming the soil around the roots. Don't let the leaves touch the sides of the terrarium, as this will most likely turn them brown.


Once your terrarium is set up, make sure that you keep an eye on the moisture level in the terrarium, misting it if it appears to be getting a little dry; at the same time, be careful not to over-water the terrarium plants, or you'll just end up with a pile of rotting plants in a nice glass box. But that's all the care your terrarium will need, and it should provide you years of green happiness.

TIP: Karen suggests, "Water your terrarium only when it becomes dry. You can tell your terrarium is becoming dry by how much condensation is forming on the walls. When there is little to no condensation you should water, and then only water lightly; misting works well. After watering, leave the lid off your terrarium until the leaves are dry. This will reduce the opportunity for disease to form on the leaves. If you find you have accidentally over watered, leave the lid off the terrarium until enough water has evaporated."

Reprinted with permission from the Sheffield School of Design.

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