How Do Terrariums Work & 10 Tips for Creating Your Very Own

Terrariums are where art and botany meet. Something about them seems otherworldly, even Jurassic! Beautiful: yes. Intimidating: Kind of. If you’re new to the world of Terrariums, this is the article for you. We will discuss the meaning of the word “Terrarium,” how they work, and how to build one. (And, no, it’s not as complicated as you think!)

“Terrariums” Meaning

Are you ready for Latin class? “Terra” means “earth” + “Arium” means “place/receptacle.” So there you have it. A terrarium is literally a receptacle for earth: a contained mini garden!

What is a Terrarium?

The basic definition aside, you may still have some questions about what a Terrarium really is. 

What kind of container do I need?

Traditionally, the “receptacle” is a closed glass container of varying shapes and sizes. 

Here lately, the Terrarium community has also (somewhat reluctantly) welcomed open glass containers, dubbing them “bowls of plants.” 

There are only two hard-fast receptacle requirements: The container shouldn’t have drainage and should be made of translucent glass.

What types of plants are suitable for a Terrarium?

There are plenty to choose from! Sealed (aka closed) Terrariums are well suited to moisture and humidity-loving plants. Open Terrariums (with no lid) are better for arid, ventilation-loving specimens. Here are a few examples:

Closed Terrarium Plants

• Ferns
• Carnivorous plants
• Tradescantia (aka Spiderwort)
• Fittonia (aka Nerve Plant)
• Calathea (aka Prayer Plant)
• Creeping Fig

Open Terrarium Plants

• Air plants
• Cacti
• Succulents
• Agave

How do Terrariums Work?

Closed Terrariums create a functioning, miniature ecosystem. Warmth and sunlight from outside the container (combined with your plant’s sweat: aka transpiration) cause condensation, watering your plant. Bacteria and other goodies within your plant’s soil continue feeding it and providing it with the carbon dioxide it needs to function.

Pretty impressive, right? Closed Terrariums can pose extra challenges (like fungal and mold issues), so expect some trial-and-error. If you’re fortunate, you’ll be like this guy, who didn’t have to open his Terrarium for 53 years!

Open Terrariums aren’t a self-contained environment, so you’ll need to actively maintain them by watering them every 3-6 weeks. (Depending on your plant’s required moisture levels.)

Creating Your Very Own Terrarium

Step One: Gather Materials

Here’s what you’ll need:

• A container: made of translucent glass, with or without a lid. Make sure your container is deep enough to accommodate the necessary layers and your growing plants.
• Soil: A clean, fresh bag.
• Drainage: Gravel, river rocks, sea glass, etc. 
• Mold/mildew control: Activated charcoal.
• Nature’s sponge: Sheet moss.
• Plants

Step Two: Adding Drainage

Place at least two inches of stones in the bottom of your Terrarium. Tall, skinny jars will need more. Why is this step necessary? Your plants will not thrive sitting in soppy soil, so it’s essential to keep the divide between the dirt and excess water.

Step Three: Mildew Control

Add ¼ inch to ½ inch of Activated Charcoal. How does this help your Terrarium work? Charcoal helps control the natural bacteria that will develop in your Terrarium. Left unchecked, the bacteria can damage your plants and stink up your house (who likes that mildew smell?).

Step Four: Nature’s Sponge

Now it’s time to add a layer of moss, which serves a few purposes. First, it keeps your soil from sinking into your rock and charcoal layers. Next, it absorbs extra moisture and humidity, keeping your plants happily watered for longer periods!

Step Five: Soil

The goal: add as much soil as possible without cramping your plants (and their potential growth). You must use fresh, sterile soil. Why? Your terrarium can quickly become a bug hotel filled with fungus gnats. That’s anything but beautiful, and they’re a pain to get rid of!

Step Six: Take a Step Back

If you haven’t already, now is the time to “landscape” your Terrarium. Where do you want to place the smaller or taller plants? What look are you going for? Take time to think it through.

Step Seven: Prepping the Plants

Now it’s time to remove your plants from their container and check out their roots! If they’re already rootbound, you should trim the roots. Why? Doing so slows down their growth, which means they’ll fit in your Terrarium for a more extended period.

Step Eight: It’s Time to Plant!

Either using your fingers or a spoon, place your plants in the soil. If you’re going for an adventurous bottle-neck Terrarium, use chopsticks, skewers, or tweezers to insert your plant through the narrow opening. Place a cork on the end of your chopstick to pat down the soil afterward.

Step Nine: Decoration Station

If you’ve opted for some decorations, now’s the time to insert them. Some plant parents go for the “fairy garden” look or insert small ceramic knick-knacks. This is part of the creative process: it’s all up to you!

Step Ten: Water Your Terrarium

Gently hose down your Terrarium with your kitchen faucet sprayer or a rosette-spigot watering can. Do so sparingly! If there’s still soil clinging to the sides of your glass jar, squirt the sides with plain water from a spray bottle. Wipe the sides down with a paper towel or microfiber cloth.

The Summary

What does “Terrarium” mean? Basically: a receptacle full of earth. How do Terrariums work? Closed Terrariums create their own mini-ecosystem, sustaining your plant with moisture and nutrients! Now that you’re a trained professional, don’t forget to tag us (@the_exotic_forest) so we can see your awesome Terrarium designs.