Closed Terrarium Care

A closed terrarium is a small, self-sustaining ecosystem. Moisture circulates naturally inside the glass, so it needs far less watering than most houseplants.

Low maintenance does not mean no maintenance. Check it occasionally, trim as needed, remove declining leaves and add water only when the terrarium shows you it is dry.

The key is knowing when to step in and when to let the ecosystem balance itself.

Watering

Closed terrariums need very little water. Always check the glass and soil before adding more.

Light morning condensation usually means the moisture level is just right.

If there has been no condensation for several days and the soil looks dry, add a small amount of water around the base of the plants.

Use a syringe, pipette or small watering bottle for better control. The soil should remain lightly moist, never soggy.

When in doubt, wait. Overwatering is far more common than underwatering.

Never water on a fixed schedule.

Larger Glass Terrariums with Acrylic Lids

When watering is needed, start with approximately ¼ cup of water, distributed gently around the plants rather than poured into one spot.

Terrarium Lamps

Terrarium lamps have an excellent seal and hold moisture especially well, so they need water much less often than terrariums with removable acrylic lids.

Watch the condensation and soil rather than watering on a schedule.

Mini Terrariums — Approximately 3” Tall

When watering is needed, start with approximately 1 tablespoon of water.

Terrarium Magnets

When watering is needed, start with approximately 1 teaspoon of water.

These amounts are starting points only. Watering needs vary with the terrarium’s size, seal, plants, temperature and light.

Light

Place your terrarium in bright, indirect light.

Avoid direct sunlight. The glass can trap heat very quickly, and temperatures inside the terrarium can become too warm for the plants.

A spot near a bright window without direct sun is ideal. A small grow light can also be used if natural light is limited.

Condensation

Condensation is a normal part of a healthy closed terrarium.

Ideal: Light morning condensation that reduces or disappears during the day.

Too wet: Heavy condensation that remains on the glass all day.

If the glass stays heavily fogged throughout the day, remove the lid for a few hours to allow excess moisture to escape, then replace it.

Repeat if necessary until you begin seeing a gentler condensation cycle.

Pruning

As your plants grow, occasional pruning will keep the terrarium balanced and tidy.

Use clean scissors to remove plants that are becoming too tall, touching the lid or crowding neighbouring plants.

Regular light pruning helps keep the terrarium full, healthy and balanced. Remove yellow, brown or dead leaves as you notice them.

Dead Leaves

An occasional yellow or dying leaf is normal. Remove it promptly to help prevent mould.

Remove any remaining dead or decaying material to keep the terrarium clean and healthy.

Long tweezers are especially helpful for reaching into deeper terrariums.

Mould

A small amount of mould may appear while a new terrarium is becoming established.

Remove the affected leaf or material and leave the lid open for a few hours to provide additional airflow.

Your terrarium contains springtails. These tiny white or orange insects are beneficial and help consume mould and decomposing organic matter.

Temperature

Normal indoor temperatures are ideal. Aim for approximately 18–24°C.

Keep your terrarium away from heating vents, fireplaces, cold drafts and areas with large temperature fluctuations.

Fertilizer

Closed terrariums generally do not need fertilizer.

The goal is slow, manageable growth. Fertilizing can encourage plants to grow too quickly and outgrow the terrarium.

Cleaning the Glass

If the inside of the glass becomes dirty or develops algae, gently wipe it with a clean microfiber cloth, paper towel or terrarium tool.

Avoid using household glass cleaners or other chemicals inside the terrarium.

Quick Troubleshooting

Heavy condensation all day?
Open the lid for a few hours to release excess moisture.

No condensation for several days + dry soil?
Add a small amount of water.

Yellow or mushy leaves?
The terrarium may be too wet. Remove damaged leaves and temporarily increase airflow.

Brown or crispy leaves?
Check the moisture level and make sure the terrarium isn’t receiving direct sunlight.

Plants getting too large?
Give them a light trim.

A little mould?
Remove the affected material and temporarily increase airflow.

The Golden Rule

Less is more, but your terrarium still benefits from an occasional check-in.

Closed terrariums are wonderfully low maintenance, but they are still living ecosystems. Check in occasionally, watch the condensation, remove declining leaves, prune when necessary and water only when your terrarium tells you it needs it.

With thoughtful, minimal care, your terrarium can thrive for years.

Warranty, Returns and Care

Each terrarium is handmade, carefully established, fully cycled and monitored under my care before it is offered for sale. Because terrariums contain living plants and are individually prepared, all sales are final and non-refundable.

If you have a concern about your terrarium, please contact me as soon as possible. While I’m unable to offer refunds, I’m happy to provide personalized guidance and support to help troubleshoot the issue and keep your terrarium healthy.

You’re also welcome to text me a photo if you’re unsure about anything—I’m always glad to take a look and offer advice.

If your terrarium has grown into a jungle or needs trimming, cleaning or other care, I provide maintenance services to help keep it healthy and looking its best.

Glasshouse Tropicals
Bringing a little more green indoors.