Growing moss in a terrarium can be so much more than a hobby. There are over ten thousand moss species and most types are used as ground cover in almost all types of terrariums.
For people with no garden, the moss becomes the green ground covering for a miniature fairy garden inside a glass terrarium, be it an empty clear glass liquor bottle, or upcycling a large lidded glass jar.
Moss only needs an enclosure, access to sunlight, and the occasional misting.
Read on to discover the intricacies involved in growing moss, the type of terrarium that works best, and the different substrate materials required to create the perfect ecosystem.
How to grow moss in a terrarium
Use a closed terrarium with a 2-inch base layer of gravel, and a half-inch layer of activated charcoal. Separate the base with landscape fabric. Add regular potting soil then tamp the moss onto the soil. Moss grows on the soil, not into it, so the soil does need to be nutrient-rich.
How moss grows
When growing anything for the first time, an understanding of the plants’ growing nature helps to get acquainted with the conditions the plant will need to not just grow but to stay alive. That sure helps!
Moss is a bryophyte meaning it has no roots or stems. Instead, it hydrates through spores on its super tiny leaves.
You can even grow moss from the spores themselves. That makes it super easy to propagate. How cool is that?
With no vascular tissue to transport water, the spores are the only way the plant can survive. For that to happen, it soaks up water like a sponge, clinging onto as much as it can.
It is not a single plant though. Moss is a collection of plants that cling close together.
For survival, they instinctively know they need to grow as a collection. The tips of the leaves produce seed pods and those produce more moss. Independently. You do not need to force them.
You can also harvest the seeds to grow moss from spores in a terrarium. It will take longer than propagating the plant.
Rhizoids are what make the magic happen
All mosses have multiple cells instead of roots. The cells are like anchors that attach the plants onto crevices between rocks, stones, and the bark of trees. You can find it growing out of crevices in buildings on garden walls, and lining the groundcover in woodlands.
In a moss terrarium, all those things you would find moss growing naturally on, you can add into your enclosure for hardscaping.
To vary the texture and style of your mini-garden in a terrarium, liverworts can be added too. These grow the same way but only on a single rhizoid.
There are over 10,000 species of moss. Every one of them is compatible with being grown in a terrarium.
How is it possible?
Excessive moisture, restricted airflow, and lots of dappled sunlight.
Like every green plant, moss uses photosynthesis. The fact that it is so absorbent makes it a terrific choice for a closed terrarium.
Why growing moss in a closed terrarium and not an open terrarium?
Because inside a closed terrarium, it is super easy to make it rain.
The moss gets misted, water filters through the substrate into the base layer where it gradually evaporates and the water vapor rehydrates the soil substrate.
As moisture evaporates from the soil, it creates condensation.
Condensation causes water droplets to trickle down the walls of a closed terrarium, falling right back into the soil.
Inside a closed terrarium, it is the same effect as a rain cycle.
On that note, to grow moss inside a closed terrarium, you need to make it rain.
Let’s make it rain…
How to set up a terrarium to grow moss
The initial setup requires a closed terrarium. Moss does not grow as well in an open terrarium because that has more air circulation. It can be done; you just need to mist it more frequently.
The terrarium you use should be glass to provide the plant with the light and heat it needs to grow. It will not grow in a dark container that blocks or filters sunlight.
Use a glass terrarium if you are growing moss to use as a display feature.
Translucent Tupperware sets are a cheaper alternative if you plan to grow multiple moss species for propagation. (Keep reading to learn more about that)
Dressing the base with a suitable substrate
Like every terrarium, the base substrate is the most important component. This is where water will be absorbed, eventually evaporating which moistens the soil from below.
The base substrate sets the stage for a rain cycle ecosystem inside a closed terrarium.
As the water will be recycled numerous times, the first component to add is for filtration. Moss will filter water, but as the water will be recycled, the more times it is filtered, the better.
The first material to layer into your terrarium is activated charcoal.
This is not the same as charcoal.
Activated charcoal is made by burning carbon-rich materials such as wood, peat, the shells of coconuts, and/or sawdust at higher temperatures than a wood fire.
The activation part is important because at higher temperatures, impurities are removed from the charcoal and the bonding capabilities are restored. That is why activated charcoal is ideal for the base layer of a closed terrarium.
It acts as a sponge that soaks up toxins. Not just in water or soil. In the body too (but do not eat it – horticultural activated charcoal is only for gardening).
In human toxicology, suspected overdoses, or alcohol poisoning from a few too many can be treated “at the hospital” with medicinal charcoal, which is activated charcoal that has been purified and then ground down into a fine powder.
It sure beats a gastric suction, aka, getting your stomach pumped.
Back on point… If you are using a glass bottle as your terrarium, use a funnel to drop in small lumps of activated charcoal. In larger terrariums, line the bottom evenly.
The base should be at least a half-inch of activated charcoal.
Add in a solid foundation
This next layer is for moisture absorption and height. Layer at least two inches of moisture absorbent materials that will hold the weight of the soil above it.
Suitable materials for a base layer that provides a solid foundation include rocks, pebbles, horticultural sand, and/or pea gravel.
This is sometimes referred to as a false bottom.
Water pools at the base of the terrarium so the height keeps the soil above it.
Build in a safety barrier
The next layer is a barrier to prevent the soil from sifting between the crevices of the rock bed at the base.
Suitable materials for this layer are anything solid and porous, such as wood bark, or wood chips.
If decoration is not at the top of your agenda, mesh wire and landscape fabric do the job. Cut it slightly bigger than you need so that the ends can be folded up at the side of the terrarium.
Add in the potting mix
Moss does not have many needs for nutrients. They grow fine in regular potting soil.
No matter the type of soil you use, it is important to sterilize the soil before it is put into a closed terrarium.
If anything is in the soil, such as mold, bacteria, algae, or hitchhikers such as having white fungus balls in soil, which are usually harmless to household plants, but sinister when put a humid closed terrarium.
Fungi, bacterial colonies, or possibly insects could engulf the terrarium.
Always sterilize soil before adding it to your terrarium. Even if it is fresh out of the bag.
Dampen the soil, wring it out until there are no water droplets when you squeeze it, then add the sterile soil to the terrarium.
Decide on the types of moss to grow and plant them
Although there are thousands of species of moss, for designing a moss terrarium, all the types fall under one of two categories. Sheet and clumping varieties.
- Pleurocarpous mosses are the type referred to as sheet moss or carpet moss.
- Acrocarpous mosses are upright growers and are referred to as clumping mosses.
For creating a ground covering with moss, plant sheet moss. They come in various sizes and can be either cut to size or the structure is thin enough to tear a patch off and plant it.
Clumping varieties are ideal for filling in spaces.
Where you add in decorations like rocks, pieces of wood, or miniature garden figurines or trinkets, plant a small clumping moss type for vertical growth. Use the sheet moss as ground cover.
Once planted, mist the terrarium with rainwater or distilled water until all the moss looks damp, then put the lid on to seal it.
Over the first few weeks, there may be some dieback. It takes moss a few weeks to acclimate to new growing conditions. During the first few weeks, look for the moss yellowing, which is a sign it needs more sunlight.
If the moss starts to turn brown, that is a sign that it needs to be misted with water. Always use distilled water, rainwater, or purified water (boiled water once cooled to room temperature).
How to propagate moss
With so many moss varieties and a plant that is in plentiful supply, you may be wondering why you would consider propagating this.
The answer is simple: To save money!
Various moss species serve multiple purposes in gardens and for houseplants. In terrariums, they add a ground cover, surround the roots that get planted in soil, and on other houseplants, it becomes an anchoring substrate.
For example, securing moss to a PVC pipe then strapping a pothos to it is how to make a pothos totem. Tying moss onto driftwood, or a wooden plaque then attaching a bifurcatum Platycerium plant to the moss with nylon wire is how to mount a staghorn fern.
Moss serves multiple uses for houseplants, in the garden, in terrariums, bioactive vivariums, and even aquariums.
When you get into growing houseplants, especially the tropical species that need constant humidity, moss is the one plant you can never have enough of.
That said, certain mosses tend to die back underwater.
As an example, in aquariums, Java moss turns brown when algae growth is depleting nutrient resources.
Macrofauna, such as arthropods and springtails feed on algae so adding a little of those tiny insects helps prevent algae growth from becoming excessive. In aquariums, the springtails become fish food. Two birds, one stone.
The majority of moss species are temperate, so they need high temperatures, high humidity, and a lot of light.
As your moss terrarium grows, it will need pruning on occasion. Especially the clumping varieties of moss as those will need to be trimmed back to keep their height in check.
When you trim them back, you can create the same type of ecosystem in a decent-sized translucent plastic container.
Tupperware sets or clear plastic storage tubs are ideal for a closed terrarium.
Create the same ecosystem as your moss terrarium (base layer, activated charcoal, pebbles or rock, etc., and regular potting soil), then press the moss cuttings onto the moistened soil, seal the container and place it somewhere that gets lots of indirect light.
Within weeks, it will start to spread.
A quick tip: Moss can be stretched. When you remove sheet moss from the terrarium, you can stretch the remaining moss around the part you tore out to rejoin it, just like a carpet joint. It is nicknamed carpet moss after all.
Frequently Asked Questions related to growing moss in a terrarium
Can I use moss from my garden or the nearby woodlands in my terrarium?
You can use any type of moss in a terrarium, however, if you have harvested moss from outdoors, be aware of hitchhikers. A range of insects, eggs, and tiny worms can be lingering under the surface. Wild moss will need to be sterilized to make sure no hitchhikers go into your terrarium with the moss.
Why does my terrarium keep fogging up?
When the moisture levels become too high, the water droplets get too thin that it creates a layer of fine mist instead of droplets. Remove the lid to let air in. As the moisture levels drop, the fogging disappears. Closed terrariums generally need airing once monthly, unless it has been overwatered.
Taking care of houseplants and gardening are my greatest passions. I am transforming my apartment into an urban jungle and am growing veggies in my indoor and outdoor garden year-round.