How to Make a Self-Sustaining Terrarium Ecosystem [Guide]

A perfectly balanced terrarium ecosystem can (in theory) last indefinitely without any real input.

But I’m afraid perfection is a little out of scope here, folks.

That said, we can still use the same principles to produce a practical, self-sustaining terrarium. The kind that can live a long, healthy life (that you can leave for a few weeks without a babysitter).

In this guide, I’ll show you everything you need to know about building a successful terrarium ecosystem that can go the distance!

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For a sealed terrarium to thrive, it has to be its own mini world – feeding, cleaning, and renewing itself just like nature does.

That makes “going bioactive” a necessary part of building a robust terrarium ecosystem.

(Or adding springtails, at least – they do most of the work. More on that later).

A healthy bioactive terrarium ecosystem has a network of plants, bugs, and microbial colonies (and sometimes other animals/pets) that work together with their environment to support the system as a whole.

Every choice of plant, container, and critter has a knock-on effect. So choose wisely.

But don’t worry – you don’t need to manage this process down to the last detail. Provided you make the right choices, it’ll naturally find the balance itself.

1. Choosing the Right Plants

Your choice of plants says a lot about the kind of environment you want to create.

If you want a healthy mix that will thrive together in the long term, I recommend steering towards these three plant qualities.

1. Select terrarium plants that will grow well (but not too well)
2. Opt for plants that are hardy and, ideally, pest/disease resistant.
3. Provide enough plant biomass to sustain the natural cycles of the terrarium.

We want a selection that will grow to be healthy and strong but in balance with each other.

Overgrowth leads to plants out-competing each other, and that’s never good.

The best way to get around this problem is to choose plants that won’t outgrow each other or the container – even when fully mature. That’s why dwarf varieties and curated miniature terrarium plants will be your best friends here, e.g.,

• Foliage: Biophytum sensitivum (Little Tree Plant).
• Vine: Pilea glauca ‘Aquamarine’
• Fern: Nephrolepis cordifolia ‘Duffii’ (Lemon Button Fern)

Both temperate and tropical plants can work nicely in a sealed environment, provided they enjoy the high humidity and moisture.

See our list of closed terrarium plants for more help.

Moss can also be helpful here, adding biomass without filling up your terrarium. Some of the “clumpy” mosses don’t really grow or spread all that much.

👉 Shop our live terrarium moss!

2. Suitable Substrate & Materials

A functioning water cycle is the lifeblood of a self-sustaining ecosystem.

Just like the circulatory system in the human body, it has many moving parts and doesn’t perform well when it’s blocked.

That’s why building a terrarium foundation that supports the movement of moisture – whilst retaining it where necessary – is the key to a healthy water cycle.

You’ll need:

1. A drainage layer – The base layer at the bottom of a closed terrarium where excess water can collect. It helps keep up humidity, prevents the substrate from becoming oversaturated, and helps facilitate the water cycle.

In terrariums, these are often called “false bottoms.”

2. A balanced substrate – Having the right kind of terrarium substrate with great drainage and water retention is a critical component of any terrarium kit (i.e., not potting soil).

It also helps if it’s bioactive (meaning it helps to support the microfauna and microbial life). Our mix contains charcoal that helps seed microbial cultures and earthworm castings for organic nutrition.

Premium Terrarium Substrate Mix

Our carefully crafted blend that balances all of your plants’ needs.

Available on the Terrarium Tribe Store.

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3. Terrarium Container Considerations

Honestly, container choice probably won’t make or break your ecosystem, but there is one general principle to keep in mind.

In the case of bioactive terrariums, bigger is often better.

Or at least a reasonable size. Something you can get your hands in and add a meaningful level of plants and materials.

More is just… more.

More space for gas exchange, more space for plants to grow, and more resources for beneficial critters and microbial colonies.

Equally, don’t stuff your terrarium like a Thanksgiving turkey. Overcrowding and poor circulation lead to anaerobic conditions, stale air pockets, and, usually, bad bacteria growth and rot. Hardly the woodland-fresh scent we’re going for…

Opt for a nice, even, spacious glass container, and you can’t go too wrong.

That’s not to say small containers can’t work. They’re just less optimal for longevity (and the likes of bottle terrariums are infinitely more difficult).

The nutrient cycle is perhaps the most difficult part to fully replicate in a terrarium.

I imagine there are thousands of different species at play in your local woodland, all working in harmony to break down and regenerate biomatter.

That said, we can enlist the help of just two tiny critters to make our lives a whole lot easier.

Priority #1: Add a colony of springtails.

At this point, we recommend everyone do this for every project, self-sustaining or otherwise.

Seriously. Adding springtails in terrariums is just that effective.

What are springtails? They’re truly tiny little bugs/insects/arthropods that love the moist, humid conditions of a closed terrarium.

They require virtually no care, and they literally eat mold – our number one closed terrarium issue. Just pop them in, and you can say goodbye to those awful white fuzzy blooms.

White Springtails Culture on Calcium-Bearing Clay

Springtail colony starter to establish a thriving bioactive terrarium ecosystem.

Available on the Terrarium Tribe Store.

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*Optional Step 2: Add a colony of isopods.

These tiny natural cleaners make a great addition to any terrarium.

Where springtails target mold, isopods target any source of decaying organic matter.

They’ll happily go to work breaking down fallen leaves or rotting wood, transforming them from a potentially deadly terrarium hazard to a wonderful new source of nutrients.

*However, they do require a bit more care and consideration. So, if you’re looking for a fully hands-off experience, you might want to just stick with springtails.

Depending on the species, they often they’ll help aerate your bioactive substrate too, keeping your plants happy and improving drainage.

Together, they make the Isopod and Springtail wombo combo!

Can you build a self-sustaining terrarium with animals?

In theory, you can add other terrarium animals into the mix, too. Isopods can handle their waste (and sometimes become a tasty snack), so there’s a virtuous cycle to be found.

But they also add a lot more complexity to the mix (e.g., ventilation, feeding, etc). Check out my vivarium guide for more on that one.

Light

Consistency is key to sustainable terrarium lighting conditions.

Of course, your plants need to get enough natural light to respire and thrive, but they shouldn’t be at risk of being scorched by direct sunlight. 

Bright, indirect light is pretty much the gold standard for most terrarium plants. 

North-facing windows are often a great choice, as they never receive direct sunlight, but they are still well-lit throughout the day. Or, you could always put your terrarium under a grow light if you really wanted to control the light source as much as possible.

👉 We use this inexpensive Sansi Grow Light.

Yellow leaves and elongated stems are often a sign of too little light, so watch out for those too.

Water

Getting the right balance of water is the trickiest part of all terrarium projects.

A healthy ecosystem must have a good balance and distribution.

Ideally, there’d be just enough water in the system to facilitate the water cycle, with no excess moisture left over to cause any problems.

Easier said than done…

Generally, I’d recommend adding water only a little at a time whenever you see signs of low moisture levels.

• No visible condensation/fogging of the glass (condensation on the glass walls is a positive sign!).
• Dry, withered foliage.
• No visible moisture at the substrate level against the glass.

For more help on watering, see my full guide to watering terrariums.

There we have it; hopefully, by now, you should be able to make a healthy miniature ecosystem that can thrive (with minimal intervention).

Forget the boring closed terrarium kits, build something dynamic and full of life!

Check out the Terrarium Tribe Store for all your terrarium supplies.