How to Make a Self Sustaining Terrarium (5 Ecosystem Tips)

A perfectly balanced terrarium ecosystem can (in theory) last indefinitely.

Something we can all aspire to. I mean, who wouldn’t want a zero-maintenance plant terrarium?

In practice, there are a variety of important elements that need to be balanced to make a truly self-sustaining terrarium.

Each one plays its part in mitigating a problem or supporting a process, and getting each one right further increases your chance of a thriving ecosystem. Helping you to make a terrarium that’ll live a long, healthy life (and you can leave for a few weeks without a babysitter).

In this article, you’ll learn all the important ingredients to a thriving closed terrarium ecosystem and how to avoid creating a hot mess.

Let’s grow together, shall we?

tropical terrarium

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What is a Terrarium Ecosystem?

First up, we need to define the boundaries of our terrarium ecosystem.

In the wild, the term “ecosystem” conjures images of the lush green Amazon rainforest or the circle of life played out on the African Savanna. But it’s actually simply defined as “a biological community of interacting organisms and their physical environment.”

So, that goes for the plants in your terrarium too.

What makes a true ecosystem is the ability of its inhabitants and their environment to work together to support the system. A series of finely-tuned life cycles and energy transfers that will make or break the system.

In practice, that means a sealed terrarium must replicate a variety of natural processes that’ll allow it to feed, clean, and restore itself.

Sounds difficult to create, but we simply need to look to the natural world for inspiration.

How to Make a Self-Sustaining Terrarium

A self-sustaining terrarium is essentially a finely balanced plant ecosystem sealed within a closed container.

That means the plants, environmental conditions, microfauna inhabitants, and even the container itself must all be carefully considered so that they can work in harmony together.

#1: Plants

As the most important (and exciting) element of any terrarium, there’s a lot to balance here.

  1. Select the right plants for terrariums that will grow well but not too well.
  2. Plants that are hardy and ideally pest/disease resistant.
  3. Provide enough plant biomass to sustain efficient life cycles.

Remember, a zero-maintenance plant terrarium is one where we should never need to prune or remove plants that get too big.

So, we must choose plants that won’t outgrow the container – even when fully mature. That’s why dwarf varieties and curated miniature terrarium plants will be your best friends here, e.g.,

Fluffy Ruffles Fern terrarium
We love to use the Fluffy Ruffles Fern in our terrariums (this one’s super cute!).

On the flip side, it’s also important to have a sufficient amount of plants to support the water cycle. Like coal in a furnace, you won’t get the fire burning till you get it hot enough and have enough material to keep it going.

More plants = more biomass = more transpiration = more condensation = more free water.

See our extensive list of sealed terrarium plants for more help.

Moss can be helpful here, too, in adding biomass without filling up your terrarium. Cushion Moss is a great “clumpy” moss option that doesn’t really grow/spread all that much.

👉 Check out the full range of live terrarium moss available on our store!

Yes, I’ll take any excuse to add as much moss as is humanly possible. (This one’s Cushion Moss).

#2: Container

I’m afraid when it comes to bioactive terrarium containers, size does matter.

I mean, you’ve nothing to prove here… but you will need enough space in your container for free gas exchange.

Oxygen and CO2 need to be able to circulate properly, as anaerobic conditions lead to unwanted bacterial growth and decomposition. If your terrarium is crammed with material, it can develop air pockets, starving some plants of their much-needed sustenance.

That’s not to say small containers can’t work, they’re just less optimal for longevity.

Large terrarium projects are simply easier to work with on a variety of levels.

Containers with awkward shapes are also a no-no; they’re much more likely to trap liquids and gasses. That makes broad, evenly shaped containers like cubes, spheres, fish tanks, and Wardian cases the best candidates.

Often the simplest containers are the best. We found this one with a completely open top – making it super easy to work with.

#3: Light

Consistency is key to sustainable terrarium lighting conditions.

Of course, your plants need to get enough 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 lighting as much as possible.

closed terrarium under growlight
Terrarium grow lights make everything easier. Ours is just an Ikea stand and simple grow bulb.

👉 We use this inexpensive Sansi Grow Light.

#4: Water

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

And just like the circulatory system in the human body, it has a lot of moving parts and doesn’t do well when it’s blocked up.

Building a terrarium foundation that supports the movement of water – whilst retaining it where necessary – is the key to a healthy water cycle. You’ll need:

  • Proper drainage – excess water must be able to pass through the substrate. We’re creating a moist environment, not a swamp. Having the right kind of terrarium substrate with great drainage and water retention is a critical component.
terrarium substrate
👉 Shop our light & fluffy Signature Terrarium Substrate Mix.
  • A reservoir – somewhere for excess water to collect at the bottom of the terrarium. The water in the reservoir helps keep up humidity, prevents the substrate from becoming oversaturated, and helps facilitate the water cycle. In terrariums, these are often called “false bottoms.”
rainforest tropical terrarium with leca layer
👉 Leca is perfect for this, and you can find leca for sale on our store.
  • The right balance of water – ideally, there’d be just enough water in the system to facilitate the water cycle. For more help on watering, see my full guide to watering terrariums.
watering a tropical terrarium
Correct watering technique is essential for terrarium longevity.

#5: Microfauna (Insects)

The decomposition process of the natural world is perhaps the most difficult part to replicate in a terrarium. There are probably thousands of different species at work in your local woodland, all working in harmony to break down and regenerate biomatter.

So yeah, that’s quite hard to orchestrate yourself…

However, we do have some species available to us that can do a good job of it all on their own

Cue the isopods and springtails combo.

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

They’ll happily go to work breaking down any dead or decaying matter. Transforming it from a potentially deadly terrarium hazard to a wonderful new source of nutrients. Mold is their favorite food, so you can say goodbye to those awful white fuzzy blooms. 

Plus, they’ll even help aerate your newly bioactive substrate, keeping your plants happy and improving drainage.

terrarium springtails
👉 Shop our Temperate White Springtails.

Terrarium Ecosystem FAQ

What is the terrarium ecosystem definition?

A terrarium is a self sustaining plant ecosystem that’s calibrated to effectively replicate all the necessary natural cycles for a thriving community of organisms.

Can you really create a closed ecosystem in a bottle?

Of course, any container that you can seal off to create a unique internal environment can form the basis of a closed ecosystem. A bottle terrarium is a classic way to do this.

Can you build a self sustaining terrarium with animals?

Absolutely, a self sustaining terrarium with animals is often called a bioactive vivarium.

Where can I find a self sustaining terrarium for sale?

It’s rare to find terrariums for sale with all the necessary components needed for a full terrarium ecosystem. But, most closed terrariums for sale can be modified to become self sustaining. Closed terrarium kits could be a good alternative.

Over to You

How long have your bioactive terrariums been able to go without any intervention?

Let us know your secrets in the comments below.

Or maybe building a paludarium is more your cup of tea?

30 thoughts on “How to Make a Self Sustaining Terrarium (5 Ecosystem Tips)”

  1. Your website is awesome I make terrariums as a hobby, and I have a terrarium clôche I just made with dried/petrified grapewood and it’s producing some of those white fuzzy mold – it’s good to know springtails will take care of that!

    1. Thanks so much! It means a lot to hear that. Yeah, driftwood can often cause mould blooms (even after it’s been boiled and scrubbed in my experience). Springtails should do the trick.

  2. Im buying my boyfriend the bits and bobs he needs to make a closed terrarium for Christmas, this has been a massive help, i was gonna use woodlouses, will they survive well in a closed terrarium?

    1. I’m so glad you found it useful Ellis 😀 Absolutely, woodlice (or isopods as they’re often called in the industry) can be a great addition to a terrarium, though different species will have require slightly different conditions and might have slightly different behaviors. Experts often recommend a little ventilation for isopods too, so if your terrarium is completely sealed you might want to think about adding a small hole or opening it up semi-regularly.

      1. I was wondering about the critter-to-ecosystem ratio, the size of the container and the biomass itself determine what a particular system can support, I reckon; any advice regarding how many and of what, that sort of thing? Thanks very much, great article.

        1. You’re absolutely right but there’s no hard and fast rules. You typically get springtails in 16oz cultures and that’s probably enough to seed a handful of small terrariums or a single large terrarium.

  3. I am planning on making one of these after seeing my science teachers self-sustaining terrarium and was wondering if a snail could survive in there? Also my teachers had a plastic wrap as a lid, would a regular jar lid (with no holes) work? And lastly, with a large jar, other then the aforementioned snails, what would be the best animals to have it there? There’s a lot of space to work with, I’m thinking creatures that are more on the cute side. Thank you!

    1. I’m sure a snail could survive (though I’d add some air holes or make it a loose seal). That being said, they’ll munch all your plants so I wouldn’t personally add a snail to a plant terrarium. Most people add springtails or isopods for their cleaning function, but whether they’re cute is definitely down to personal preference – the rubber ducky ones are kinda cute 🤔

    1. You can, but bringing in garden soil also brings in a lot of other unknown factors (e.g. bacteria, fungus, etc) so there’s an extra element of risk to your terrarium.

  4. Renz Joshua De Vera

    Hi! I’m planning to create connected biospheres. One terrarium, one desserted and one aquatic. More of like a mini world. Is that possible?

    1. Really interesting concept! A terrarium connected to an aquarium might work as it’ll help to boost the ambient humidity, but that extra humidity would probably harm a connected desert biosphere.

      1. Renz Joshua De Vera

        I placed the desert terrarium way higher than rainforest terrarium. Then i placed the aquarium beside the enclosed terrarium. I do it so that the humid air (since it is heavier than dry air) will just settle at the bottom. There is a thin tube connected to the desert above just to continue water cycle and balance out the temperature in the rainforest terrarium. So far, it turns out quite well and the desert terrarium is not affected but still contributing to the whole biosphere. I’m just worried in the next months. I would love if i can upload pictures here. Thanks! You are an absolute help.

  5. Would a big jar like a cookie jar (clear glass) w a lid work to create terrarium? 64oz? basically, a cylinder that is semi-tall with a glass, lid.

  6. Is any time of predation needed for a self sustaining ecosystem? Wouldn’t the wood louse and spring tails just consume and breed until they wipe out any plant life?

    1. They seem to be self-regulating for the most part. Springtails will never eat your plants and can only grow their colony to a size that’s supported by the natural decay of your terrarium.

  7. Does the temperature of the room the terrarium is in matter? I’m in Michigan and it get’s cold, even inside. I’d like to make one, especially with moss, and keep it at work, but that’d mean it being ok in a room that ranges from high 50s to low 80s depending on the season (our heating/cooling system sucks).

    1. It depends on the plants really, but most terrarium plants are tropical in nature and won’t do well in cold conditions. It’s cold here in the UK but we blast the central heating in Winter 😄

      1. Hi Dan – to build on the question of terrariums in a cold climate: would it be possible to maybe add a lighting element for cold nights? Growing up, we would occasionally use Christmas lights to mitigate hard freezes on our fruit trees, so maybe having a nearby lamp, or a tiny string of lights around the jar could keep things from getting too cold?

        1. Possibly! I tend to use a grow light with my terrariums in Winter anyway but I’m not sure it puts out that much heat. Failing that, I’ve also got a cheap heating mat (for seedlings I believe) that can keep my terrarium toasty on extra cold nights.

  8. Is charcoal instead of rocks or pebbles? Im doing a science project about self sustaining terrariums and need to know… thanks

  9. Hi Dan! I loved the post. I am a naturalist at a park and I am leading a build your own terrarium program for kids. I’m not sure on the containers they will bring but I was wondering if they need to be closed containers or if they can spritz them if they don’t have a lid. I don’t trust that the public will keep them alive so we are foraging for a few plants and will only add a few insects so they don’t cause too much harm.

    1. Hi Shannon, closed containers are necessary I’m afraid. Spritzing regularly would help, but it’s probably only delaying the inevitable, and it’ll never actually form an ecosystem.

  10. Hi Dan, Just wanted to say thanks for this awesome post! I got into houseplants over lockdown, but now that I’m back in the office, I just can’t keep up with them anymore. So I’m considering a self-sustaining terrarium (or many!) instead, and this page was a great introduction! Thank you!

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