Caring for your terrarium

How much light does a terrarium need?

Place your terrarium in bright, indirect light.

Avoid:

• Direct sun through windows - this can overheat the glass and damage plants
• Dark corners with little natural light
• Harsh afternoon sun

Think bright room, filtered light.

How does humidity work in a terrarium?

Humidity is what makes a terrarium so easy to live with. In a closed terrarium or Mossarium, water evaporates, gathers on the glass and returns to the soil, a small water cycle that keeps the air moist without your help. This is why closed pieces rarely need watering, and why a little mist on the glass is a good sign rather than a problem. Open and ventilated terrariums hold less humidity, so they lean on you a little more.

How often should you water a terrarium?

What kind of terrarium do you have?

Care depends on the type of terrarium you have. Closed terrariums have a lid and recycle their own moisture, so they need watering only rarely. Ventilated terrariums have small holes at the top and lose moisture a little faster. Open terrariums have no seal, so moisture escapes and they need the most regular watering. Mossariums are moss gardens under glass and are cared for like a closed terrarium, with extra attention to water quality.

Closed terrariums (with lids) and Mossariums

Closed terrariums and Mossariums create their own miniature water cycle and rarely need watering. Check the soil, and if it feels dry, spray lightly. Rain, distilled or filtered water is preferred, but if you don't have that, then just tap water will do.

Mossariums can be particularly sensitive to water and heat, and we recommend being more careful with them. A little tap water is fine, but too much can make them go brown, so having some rainwater or distilled water on hand is a good idea.

You may notice light condensation - this is normal and tells you the cycle is working. See the Condensation section below for guidance on what you're seeing.

With Closed terrariums, less is more.

Ventilated terrariums (with holes)

Ventilated terrariums have small holes at the top and lose moisture more quickly than closed terrariums. Check the soil regularly, particularly in summer, and if it feels dry, spray it with rainwater, distilled water, or filtered water. If you don't have that, then tap water will do. After you live with your terrarium for a while, you will learn how much water it needs to thrive.

Ventilated terrariums require just a little more care than a closed terrarium.

Open terrariums

Open terrariums require more regular care as moisture naturally escapes.

Regular watering is required, but avoid overwatering, especially with terrariums that have a shallow base, as you don't want water pooling in the bottom. Check the soil and spray with rainwater, distilled water, or filtered water. If you don't have that, then tap water will do. After you live with your terrarium for a while, you will learn how much water it needs to thrive.

Open terrariums are a little garden and require regular care.

What does condensation in a terrarium mean?

Seeing mist or fog on the glass? That's your terrarium's water cycle at work.

How do you prune and maintain a terrarium?

Plants will continue to grow.

Trim any leaves touching the glass to:

• Maintain airflow
• Prevent excess moisture build-up
• Keep your terrarium looking good

Remove any yellowing leaves as needed.

What temperature suits a terrarium?

Keep indoors in a stable environment.

Avoid placing near:

• Heaters
• Air conditioners
• Fireplaces
• Hot windows

Common terrarium problems, and how to fix them

Why is the moss going brown or yellow?

Browning usually means too much water, tap water, heat or direct sun. Move the piece into bright, indirect light and away from any heat source, ease off watering, and when you do water, use rainwater or distilled water and mist lightly. Moss recovers slowly, so give it a few weeks.

There is too much condensation on the glass.

Heavy, lasting fog means there is a little more moisture than the terrarium needs. Take the lid off for a short while to let some escape, then put it back. A light mist that clears through the day is normal and means the water cycle is working.

There is no condensation at all in my closed terrarium.

In a sealed terrarium, no condensation usually means it is a touch dry. Mist lightly, replace the lid, and check again the next day. You are looking for a soft mist on the glass, not streaming water.

How do I deal with mould or a musty smell?

Occasionally a new terrarium shows a little surface mould as it settles. Remove any affected material, increase airflow by taking the lid off for a while, and cut back on watering. Keeping it in bright, indirect light and trimming leaves that touch the glass helps prevent it returning.

The plants are touching or fogging up the glass.

This is simply growth. Trim any leaves pressing on the glass to keep airflow and reduce excess moisture, and remove yellowing leaves as they appear. A terrarium is meant to grow and change, so light, occasional pruning is all it needs.

Caring for a terrarium through the seasons

A terrarium shifts a little with the seasons, and a small amount of attention keeps it happy. In summer, warmth means faster evaporation, so open and ventilated terrariums may need water more often, and everything should be kept well clear of hot windows and direct sun. In winter, growth slows and pieces need less water, but keep them away from heaters and cold draughts, which dry the air and swing the temperature. Closed terrariums and Mossariums stay the steadiest year-round, because their own humidity buffers most of the change.

Caring for moss specifically

Moss is forgiving, but it has a few preferences. It likes bright, indirect light and a humid, enclosed space, which is exactly what a Mossarium provides. It is sensitive to water quality and heat, so rainwater or distilled water is best, tap water in small amounts is fine, and too much of anything can turn it brown. When it looks a little flat or dull, a light misting usually brings it back. About once a week, it is good to lift the glass lid off for a few minutes to refresh the air inside, then pop it back on. This is not extra watering, just a brief airing that keeps things fresh and discourages stale air and mould, while the enclosed glass still keeps its own humidity the rest of the time. Moss grows slowly, so patience is part of the pleasure.

A living piece of nature

Every terrarium is unique and will continue to evolve over time.

Small changes, new growth and seasonal variation are all part of the experience.

Every terrarium is its own small world, and no two behave in quite the same way. Live with yours for a while and you will learn its rhythm: how much light it likes, how often it wants misting, and how it changes through the year.