The most detailed guides on the internet for plant and terrarium maintenance, creation and care.
What are the Essential Components of a Terrarium?
What are the Essential Components of a Terrarium?

What are the Essential Components of a Terrarium?

Let’s explore the ins and outs of terrarium creation and maintenance through the different components needed.


lots of variations of terrariums in long containers

Types of Containers

The first thing you need for a terrarium is, of course, the container.

This is the ‘canvas’ where you’ll create your small, self-sustaining world.

A range of containers can be used, from repurposed glass jars and fish tanks to specially designed terrarium containers.

Glass cloches, mason jars, vases, or even clear plastic containers can be repurposed into a terrarium.

Choosing the Right Container

The choice of container depends largely on the type of terrarium you’re creating.

Closed terrariums require a container with a lid or a cork to maintain humidity, while open terrariums can be housed in any open container.

The key is to ensure your container is clear, to allow light to reach your plants, and that it’s clean, to prevent the growth of unwanted mold and bacteria.

Base Layers

Your terrarium needs layers at the base for drainage and to create the right environment for your plants.

Gravel or Pebbles

The first layer in your terrarium should be small pebbles or gravel.

This provides drainage and prevents water from stagnating at the roots of your plants, which could lead to root rot.

We would advise making this layer anywhere from 2 to 4 inches in height (depending on the size of container).


image of wooden spoon on top of ground activated charcoal

Activated charcoal, often used in aquarium filters, comes next.

This layer helps to purify the water and prevent the buildup of fungi and bacteria in your terrarium.

This component should be thinly spread above the stones/ pebbles placed below, as this layer will get mixed around when water is added.

Activated charcoal can be sourced from pet stores, garden stores, or commonly bought on most marketplaces.


up close photo of moss on a forest floor

Sphagnum moss or any other kind of dry moss makes up the next layer.

It acts as a barrier, preventing the soil from seeping down into the gravel and charcoal layers.

This layer should be around half an inch to an inch in height, and should totally cover the layers below to avoid a breach of soil into the water.

Potting Soil

image of detailed layers of soil in the ground

On top of these layers, add a layer of well-draining potting soil – this is where your plants will live and grow.

The type of soil used can depend on the specific plants you’re planning to include in your terrarium.

Generally this should be the tallest layer, depending on the size of the roots of your desired plants.

We would suggest 3 to 5 inches of soil in areas where plant roots will be dense.


lots of varieties of air plants in green, purple and white

Suitable Plants for Terrariums

Here are seven popular plants often used in terrariums, however please research this further to decide which best would suit your environment and available space.

Ferns: Miniature ferns like Button Fern (Pellaea rotundifolia) and Lemon Button Fern (Nephrolepis cordifolia) are excellent choices. They love the humid environment that a terrarium provides and do well in low to medium light.

Mosses: Mosses, such as Sheet Moss or Cushion Moss, are perfect for terrariums due to their love of humidity and low light conditions. They also add a lush, green carpet that can give your terrarium a magical, woodland feel.

Baby Tears (Soleirolia soleirolii): This plant has a charming, delicate appearance with tiny round leaves and creeping stems. It thrives in humid conditions.

Spider Plant (Chlorophytum comosum): Known for its long, slender leaves, the spider plant is a hardy choice and can tolerate a variety of conditions. Dwarf varieties are best for terrariums due to their smaller size.

Golden Pothos (Epipremnum aureum): Pothos is a hardy plant that’s easy to care for. It’s a trailing plant, which can add some nice visual interest to your terrarium. It does well in a range of lighting conditions.

Fittonia (Fittonia argyroneura): Also known as nerve plant, Fittonia adds a pop of color to your terrarium with its vein-like patterns. It loves high humidity and indirect light.

Polka Dot Plant (Hypoestes phyllostachya): With its vibrant leaves dotted with different colors, the Polka Dot Plant is a great way to add some color to your terrarium. It does well in humid conditions and prefers indirect light.

Planting Techniques in Terrariums

women potting plants in a dome shaped terrarium

When it comes to planting, use a spoon or a small gardening tool to dig a hole in the soil.

Remove the plant from its container, gently loosen the roots, and place it in the hole.

Cover the roots with soil and gently press down again – if required you can steady the plant with surrounding materials like rocks, or even some plant-safe glues.


Understanding the Microclimate of a Terrarium

A terrarium, whether open or closed, creates a unique microclimate.

Closed terrariums tend to be humid and warm, simulating a rainforest environment, while open terrariums are drier and cooler, more akin to a desert environment.

If you are a beginner to the terrarium world, read more on how you can setup your first terrarium here.

Factors Affecting the Microclimate

the terrarium water cycle graphic

Monitoring the microclimate of your terrarium involves keeping a close eye on several key factors that affect the health of your plants. Here are some steps you can take:

Temperature: Maintain a consistent temperature in the environment surrounding your terrarium. Extreme temperature changes can harm the plants inside. Keep your terrarium away from radiators, air conditioning vents, or drafty windows. You can use a small thermometer inside the terrarium to monitor temperature if needed.

Light: Observe your plants for signs of too much or too little light. If your plants are getting brown or scorched leaves, they may be getting too much light. If they become leggy (grow tall and spindly) or their color fades, they may need more light. Move your terrarium to a location with appropriate light levels based on the plants’ needs.

Humidity: For closed terrariums, observe the amount of condensation on the glass. If the walls are always foggy, and visibility into the terrarium is obscured, it may be too humid, and you should open the terrarium to let some moisture out. On the other hand, if the terrarium appears too dry, you may need to add water. For open terrariums, the soil should be kept slightly damp. A hygrometer, which measures humidity, can be a useful tool for monitoring this.

Water: Overwatering is a common problem in terrariums. The soil should be moist, but not waterlogged. If water pools at the bottom, or if mold and algae begin to grow, your terrarium may be getting too much water.

Plant Health: Regularly check your plants for signs of disease or stress, such as yellowing leaves, spots, or slow growth. This can help you catch any issues early and take corrective action.

Ventilation: For closed terrariums, it’s important to remove the lid every now and then to allow fresh air in. This can prevent the buildup of too much humidity and help deter mold and mildew growth.

By regularly monitoring these factors, you can ensure that your terrarium maintains a healthy microclimate for your plants to thrive.

In Conclusion…

By understanding the essential components of a terrarium and how they interact, you can create a balanced ecosystem that will thrive with minimal care, bringing life and tranquility into your home or office.

If you’re looking to find out more about terrariums, take a look at our ultimate guide to terrariums.