Make a Terrarium: An Overview
I first got the idea of encasing and growing plants in glass when he noticed a fern had sprouted in the soil of a sealed bottle he was using to rear moths.Watching the cycle of moisture condensing and rolling back down into the soil, he wondered if maintaining exotic specimen plants in a glass container in this way would increase their odds of survival during transport from their native countries to England.He was right, and moreover, the Wardian cases he developed for this purpose became immensely popular with fashionable Englanders, contributing to the Victorian orchid hunting and collecting explosion.
What we now know as a terrarium
The research and innovations of Dr. Ward became what we now know as a terrarium, an ecosystem within a container allowing the gardener to exhibit a variety of species, particularly moisture-loving species, with a much higher rate of success.The enclosed habitat locks in moisture and heat, protects from draft and air pollution, prevents damage from insects, pets, or children, and protects the plant from over and under watering that can easily kill a high maintenance tropical.Aside from aesthetics, the main selling point of the terrarium is that maintenance drops down to near zero, making it easy for even beginner gardeners to bring unusual plants into the home—this is because the environment inside of the glass mimics the environment outside, so they won’t need constant interference from you to get the desired amount of water and humidity.
At some point in school, you’ve probably studied the water cycle: rain Autumns down from the sky, drains into the soil to water vegetation and fill rivers and lakes, evaporates back into the air, condenses in the clouds, and eventually becomes precipitation again. A closed terrarium replicates this water cycle on a much smaller scale. When you water your terrarium, that water becomes trapped in the container, so instead of evaporating into the atmosphere, it evaporates and condenses on the lid and sides of the container. This condensation will drip or roll back down the sides and remoisten the soil like the rain, over and over again. An occasional misting from you is all that your terrarium plants will need to keep this process going—it’s like harnessing the natural and essential life cycle of water to create a self-watering planter.
What You Need
While terrariums, especially large ones with a lot of variety, can look intimidating to put together, it’s actually very, very easy—anyone can put together a terrarium.You will need:
A container: This can be any container you want or may already have, but it must be a clear container that light may pass through easily. Select a container that will suit the size of the plants you want to have (you don’t want them to be mushed up against the sides of your container), and one that you will be able to reach into to manipulate soil and plants when planting. If the mouth of the container is too small for you to be able to work, you will also need spoons, chopsticks, a stick, or some other long tool to help you work. We really like to use glass apothecary jars, clear glass cookie jars, and other decorative lidded jars that we may find in a craft store.
Pea gravel or river stone: These are for the bottom of your display to help with drainage.
Garden charcoal: These charcoal flakes will absorb any wet odours that the soil might produce, and help to keep bacteria in check.
Light potting soil: Choose a potting soil without fertiliser (fertilisers will encourage vigorous growth, and this is what you don’t want in a small container) that’s very lightweight. Heavy composty potting soils or top soils may become packed down and sodden with moisture, preventing the excellent drainage you’ll need to keep roots from rotting or having fungus problems.
Plants: There are a great many plants suitable for a closed terrarium, and you’ll find that an increasing number of nurseries are offering more and more in the way of small plants for terrariums and fairy gardens. In general, you’re looking for plants that love a wet, humid environment, and don’t mind being a few degrees on the warmer side. African violets, ferns, mosses and lichens, baby’s tears, bromeliads, begonias, and many, many others are great choices for a closed terrarium.
Accessories: Sticks, stones, beads, miniature garden figures and furniture—many terrarium-makers like to create small gardens in the container, so consider creating a small scene.
Building the Terrarium
- 1.First, you’ll add your substrate, which will be three layers of gravel, charcoal, and soil.How much you add of each isn’t an exact science, but you’ll want to make sure that you’re using enough for the size of your container.Make sure that your plants have enough soil to cover their roots. This is usually around one third of the size of the container.
- 2.Add a layer of gravel to the container. Be sure to at least cover the bottom of the container, but use as much as you would like if you like the look of it.
- 3.Next, add a thin layer of charcoal. Again, cover the bottom layer completely before adding soil.You may want to reserve a few pieces to mix with the soil if you’d like.
- 4.Pre-moisten your soil so that you won’t have to soak your terrarium after it is planted. Be sure not to add too much water—it should be light, fluffy, and just slightly moist. Add the soil on top of your charcoal layer, making sure to use enough for the roots of your plants.
- 5.Now, you can add your plants! Place your plants however you’d like them arranged in your terrarium, keeping in mind how you’ll be viewing it in your home. Make sure that your taller plants are behind your shorter plants.Try not to place anything so that it is mushed against the glass—these can become waterlogged and rot.When you are satisfied, pack them in tightly and add any soil you may need to cover up the roots.
- 6.If you have any decorative accessories you’d like to add, you can place them now.
- 7.When you are finished, spritz the sides of your container with water—not too much—until it just begins to roll down.You may also want to hit your soil with just a few mists, also. When you are done, you can close up the jar.
Maintaining Your Terrarium
Once your terrarium is closed, you shouldn’t need to water for quite a while. You’re looking for very light condensation on the sides and lid of your container. If you see large beads of water forming and trickling down, you may want to remove the lid and air your terrarium out—too much water will result in rot.If you see no condensation at all, you can add a few spritzes to the sides and soil.Either way, it is recommended that you tilt the lid for a couple of hours every week or so to allow for some drying out to discourage mould or rot.
Terrariums should receive only bright indirect light, so they are best indoors. Never expose it to direct light as heat can’t escape the terrarium, and it could cook the plants inside.
You will not and should not fertilise the terrarium. Fertiliser will cause a growth spike, and overgrown plants in terrariums will rot.
If your plants need to be pruned, go ahead and pinch them back to keep them down to size.Don’t allow plants to grow wild in the terrarium.