Terrariums are more than glass containers for reptiles. They can also be miniature plant worlds — with moss, plants, soil, stones and moisture working together inside a small space.
When you hear the word terrarium, you might picture a lizard, snake or another reptile.
But a terrarium can be something completely different.
It can be a small garden in glass.
A quiet corner of nature on a desk, shelf or bedside table. A miniature landscape that changes slowly as plants grow, moss spreads and moisture moves through the system.
At MossBoss, we focus on plant terrariums — small living worlds created with plants, moss and natural materials. They can be closed, open or bioactive, when small soil-dwelling organisms such as springtails and isopods are introduced into the plant environment.
What Is a Terrarium?
A terrarium is a transparent container used to create a controlled environment for plants or other terrestrial organisms.
Plant terrariums are usually made from glass and can be either closed or open.
A closed terrarium creates a more humid environment where moisture can circulate inside the container. An open terrarium allows more air exchange and is better suited to plants that prefer drier conditions.
Terrariums are also used as decorative miniature landscapes, combining living plants with natural materials such as moss, stones, sand and wood.
So when someone asks:
“What is a terrarium?”
the answer isn't simply “a glass enclosure for reptiles.”
A terrarium can also be a miniature plant ecosystem in glass.
Are Terrariums Only for Lizards and Snakes?
No.
The word terrarium is used for different kinds of terrestrial environments.
Some are designed for reptiles and other animals.
Others are designed entirely around plants.
A plant terrarium is a transparent container in which plants are grown in a controlled environment. Depending on the design, it can contain moss, small tropical plants, ferns, succulents or other plants suited to the conditions inside.
This is the type of terrarium we create at MossBoss.
No reptiles required. 🌿
How Does a Plant Terrarium Work?
A terrarium is more than a plant placed inside a glass container.
The container changes the environment around the plants.
In a closed terrarium, water can move through a small internal cycle:
moisture → evaporation → condensation → return to the substrate
Want to understand condensation better? Read our [Terrarium Condensation Explained].
Water is released from the substrate and plants into the air. Some of that moisture condenses on the cooler surfaces of the container and eventually returns to the growing medium.
Light entering through the transparent container also allows plants to photosynthesize.
Light is another important part of the system. Learn more in our [Terrarium Light Explained: The Complete Guide].
This combination creates a small, humid environment that can be very different from the air outside the container.
But there is an important distinction:
A closed terrarium can be highly self-sustaining, but it is not automatically maintenance-free.
The balance depends on the plants, amount of moisture, light, container and conditions inside the terrarium.
That is why at MossBoss we don't think of a terrarium as something you simply build and forget.
A terrarium is something you observe.
What Is a Bioactive Terrarium?
A bioactive terrarium is a terrarium that contains not only plants and substrate, but also small living organisms that participate in breaking down organic matter and supporting the environment.
In plant-based bioactive terrariums, two of the most commonly used organisms are springtails (Collembola) and isopods.
Springtails
Springtails are tiny soil-dwelling organisms that mainly feed on fungi, organic debris and other decomposing matter.
In a terrarium, they are part of the natural detrital cycle — helping break down organic material and, under suitable conditions, helping keep excess mold growth under control.
Isopods
Isopods, commonly known as woodlice, are small crustaceans that live in soil and other moist organic environments.
They feed on dead plant material and other organic debris, contributing to decomposition and helping return nutrients to the substrate.
🌿 What Makes a Terrarium Bioactive?
Simply adding springtails or isopods does not automatically make a terrarium bioactive.
A bioactive terrarium is a connected living system, where different parts work together:
plants → organic matter → microorganisms and decomposers → decomposition → nutrients → plants
This is one of the most interesting aspects of a bioactive terrarium. Instead of observing plants alone, you can observe the interaction between different parts of a small ecosystem.
An Important Distinction
Bioactive does not mean “maintenance-free” or “self-sustaining forever.”
The system still needs to be properly established and observed. The organisms, humidity, substrate, plants and terrarium size all need to be appropriate for one another.
Closed vs. Open Terrariums
One of the simplest ways to understand plant terrariums is to divide them into two types.
| Closed Terrarium | Open Terrarium | |
|---|---|---|
| Environment | Humid, enclosed | More open to surrounding air |
| Moisture | Moisture can circulate inside | Moisture escapes more easily |
| Suitable plants | Mosses, ferns, Fittonia and other moisture-loving plants | Succulents, cacti and other plants suited to drier conditions |
| Watering | Usually infrequent | More similar to conventional plant care |
| Main feature | Humid microclimate | Better ventilation and lower humidity |
The distinction is important because the container should match the plants.
RHS recommends small, slow-growing foliage plants, miniature ferns and mosses for sealed terrariums, while open terrariums are particularly suitable for succulents and cacti.
What Is a Closed Terrarium?
A closed terrarium has a lid, stopper or other way of enclosing the growing environment.
The enclosed space helps retain humidity and allows water to circulate within the container.
This makes closed terrariums particularly suitable for plants that enjoy humid conditions, including:
- mosses
- Fittonia
- small ferns
- Peperomia
- Pilea
- other small, slow-growing tropical plants
The goal isn't simply to keep the container wet.
The goal is to create a balanced humid environment where plants can grow without constantly adding water.
A little condensation can be part of that process. Heavy, persistent condensation, however, can indicate that the system contains more moisture than it needs.
Terrarium Watering Explained →
What Is an Open Terrarium?
An open terrarium has an opening that allows more air exchange and moisture loss.
Because humidity is generally lower, open terrariums are suitable for plants that don't need a constantly humid environment.
This makes them particularly useful for:
- succulents
- cacti
- drought-tolerant plants
- some airier plant compositions
Open terrariums still create a distinct miniature landscape, but their environmental conditions are closer to those of ordinary indoor plants.
What Is the Difference Between a Terrarium and a Florarium?
You may also come across the word florarium.
In everyday use, florarium generally refers to a plant-focused arrangement or miniature plant environment inside a transparent container.
The terms plant terrarium and florarium often overlap.
You may also see descriptions such as:
- plant terrarium
- terrarium for plants
- terrarium with plants
- florarium
- miniature garden in glass
- garden in a jar
- forest in glass
- miniature landscape
These terms don't always describe exactly the same construction.
But they share a common idea:
A small plant world contained within a limited space.
At MossBoss, we use plant terrarium because it clearly describes what we create: a small living plant environment in glass.
What Is a Miniature Garden in Glass?
A miniature garden is a broader concept.
It can be created in a pot, bowl, tray or other container.
When a miniature garden is built inside a transparent container and creates a distinct growing environment, it can function as a plant terrarium or florarium.
This is why you may find similar products described in different ways:
Terrarium.
Florarium.
Miniature garden.
Garden in glass.
Forest in glass.
Sometimes the difference is technical.
Sometimes it is simply the language used to describe the finished composition.
What matters most is understanding the environment you are creating and the plants you are putting inside it.
What Plants Can Grow in a Terrarium?
There is no single list of plants that belongs in every terrarium.
The first question should always be:
What conditions will the terrarium provide?
Plants for closed terrariums
Closed, humid terrariums are generally suited to small plants that appreciate higher humidity.
Examples include:
- mosses
- Fittonia
- small ferns
- Peperomia
- Pilea
- other small, slow-growing tropical foliage plants
Plants for open terrariums
Open terrariums are better suited to plants that prefer lower humidity and better air exchange.
Examples include:
- succulents
- cacti
- other drought-tolerant plants
RHS and Kew both emphasize matching plants to the humidity and ventilation of the terrarium rather than treating all terrariums as the same environment.
Can You Put Succulents in a Terrarium?
Yes — but usually in an open terrarium.
Succulents store water in their leaves or stems and are adapted to drier environments.
A permanently humid, closed environment is therefore generally not the right setting for them.
An open glass container can provide the miniature landscape effect of a terrarium while allowing more air exchange and moisture to escape.
This is why a composition with:
succulents + stones + sand + an open glass vessel
can be very different from:
moss + Fittonia + humid substrate + a closed glass vessel.
Both can be plant terrariums.
They simply create different environments.
What Goes Inside a Plant Terrarium?
There isn't one universal recipe.
The materials depend on the container, plants and type of terrarium.
A plant terrarium may contain:
- a glass container
- a drainage layer
- a separating mesh
- substrate
- activated charcoal
- live moss
- live plants
- decorative gravel
- sand
- stones
- wood or other natural elements
Not every terrarium needs every material.
For example, the structure of a closed MossBoss terrarium differs from that of an open succulent composition.
The materials should serve the plants and the environment — not the other way around.
For a deeper look at how the different layers work together, see our [Terrarium Layers Explained: The Complete Guide].
Terrarium, Plant Pot or Miniature Garden?
They may all contain plants, but they serve different purposes.
A plant pot
A plant pot is primarily a container for growing an individual plant or group of plants.
A miniature garden
A miniature garden focuses on creating a small landscape or composition.
A terrarium
A terrarium creates a more contained environment around the plants, especially when the container is enclosed.
Closed terrariums can retain humidity and recycle moisture within the vessel, while open terrariums provide a more ventilated environment.
Terrariums are also often designed as miniature landscapes and decorative objects, combining horticulture with composition and natural materials.
How Much Care Does a Terrarium Need?
This depends on the type.
A well-balanced closed terrarium can require very little watering because moisture is retained and recirculated within the container. RHS notes that sealed terrariums may need very little maintenance once established.
But low maintenance does not mean no observation.
Instead of following a fixed watering calendar, pay attention to what the terrarium is telling you:
- Is there light condensation?
- Is the substrate still moist?
- Does the moss look healthy?
- Are the plants growing normally?
- Is there excessive, persistent moisture?
- Are dead leaves accumulating?
At MossBoss, this is one of the most important parts of caring for a terrarium:
Observe before you act.
A terrarium doesn't need you to interfere constantly.
It needs you to notice what is happening.
Where Should You Put a Terrarium?
Terrarium plants generally need bright, indirect light.
Avoid placing a glass terrarium in strong direct sunlight, especially for long periods.
The transparent container can trap heat, and intense sunlight can damage plants or cause the interior temperature to rise too much.
A bright position away from direct midday or summer sun is usually a better starting point.
And remember:
More light is not always better.
The goal is suitable light for the plants inside the container.
A Brief History of the Terrarium
The story of the modern plant terrarium is closely connected with Nathaniel Bagshaw Ward and the Wardian case.
In the 19th century, Ward observed a fern growing inside a sealed glass container. His observations eventually led to the development of the Wardian case — a portable glass enclosure that made it possible to transport living plants over long distances.
Kew describes Wardian cases as an important development in botanical exploration and the transportation of plants around the world.
What began as a practical way to keep plants alive during transportation also revealed something fascinating:
plants could create and maintain a small environment inside a glass enclosure.
That idea continues to inspire terrariums today.
A Terrarium Is a Landscape in Miniature
A terrarium can be technically small while still containing a surprising amount of life.
A new leaf appears.
Moss slowly spreads.
Condensation changes with the weather.
The substrate becomes lighter as it dries.
Plants grow toward the light.
A landscape that looked finished on the day you built it continues to change.
This is what makes a terrarium different from a static decoration.
It is a small living system that you can observe over time.
And that is where the MossBoss philosophy begins.
How Do You Start Your Own Terrarium?
Start with one simple question:
What kind of small world do you want to create?
A humid, enclosed forest floor with moss and small tropical plants?
Or an open, drier landscape with succulents, stones and sand?
Once you know the environment you want, choosing the container, plants and materials becomes much easier.
If you are ready to build one, continue with our practical guide:
How to Make a Terrarium at Home →
Frequently Asked Questions
Is a terrarium only for reptiles?
No. Terrariums can also be designed entirely for plants. MossBoss focuses on plant terrariums and miniature plant ecosystems.
What is a plant terrarium?
A plant terrarium is a transparent container used to grow plants in a contained environment. It can be open or closed depending on the plants and conditions required.
What is a florarium?
A florarium is a plant-focused arrangement or miniature plant environment in a transparent container. The term often overlaps with “plant terrarium.”
What is the difference between a closed and open terrarium?
A closed terrarium retains more humidity and allows moisture to circulate inside the container. An open terrarium allows greater air exchange and is better suited to plants that prefer drier conditions.
Can succulents grow in a terrarium?
Yes. Succulents are generally better suited to open terrariums rather than humid, sealed environments.
Can moss grow in a terrarium?
Yes. Moss is particularly well suited to humid, closed plant terrariums when the other conditions are appropriate.
Does a terrarium water itself?
A closed terrarium can recycle much of its moisture, but it should not automatically be considered maintenance-free. Light, moisture, plant choice and the balance of the system all matter.
Does a terrarium need to be closed?
No. Terrariums can be either open or closed.
Can any glass container become a terrarium?
Many clear glass containers can be used, provided they are suitable for the plants and the type of environment you want to create. The shape, opening, depth, light exposure and ability to control moisture all matter.
A Note from MossBoss
A terrarium doesn't have to be big to contain a world.
Sometimes all it takes is a glass vessel, a little moss, a few plants and enough time to see what happens.
We believe a terrarium is not something to rush.
Observe. Record. Understand. Grow.
Welcome to your little world.
