Care Tips for Mossariums & Terrariums

We design closed terrariums typically topped with a cork or acrylic lid. When the plants are primarily moss, we call them mossariums.

Closed terrariums create a tiny self-sustaining ecosystem. They need very little care—just a few occasional check-ins.

Light

• Place in bright, indirect light.

• Avoid direct sunlight (it can overheat the sealed environment).

• Grow lights are fine if kept 8–12 inches away.

Watering
Closed terrariums need very little extra water.

• Mist only if the moss looks dull, pale, or dry, which is uncommon.

• Use just 1–2 light mists at a time—never saturate.

• The more often you remove the lid, the more often you will need to water.

• Each terrarium has a layer of rock and horticultural charcoal at the bottom. If you see water in this bottom layer, stop watering! This layer is only for overflow.

Condensation (Normal!)
Closed terrariums naturally cycle moisture.

• Light morning condensation: Perfect.

• Heavy fog or dripping water: Too wet → vent by removing the lid for a few hours.

• No condensation for several days: Too dry → add a single light mist.

Airflow / Venting

How often you need to vent depends on the lid type:

Cork Lids

• Cork allows slow, natural airflow, so minimal venting is needed.

• Open the terrarium for 1–2 hours every 2–4 weeks, or only when moisture is high.

Acrylic Disc Lids

• Acrylic creates a tighter seal with little to no natural airflow.

• Vent briefly every 2 weeks to keep humidity balanced.

• If mold appears, remove the lid for 12–24 hours.

Cleaning

• If algae appears inside the glass, wipe gently with a long cotton swab or soft brush.

• Remove any bits of debris so they don’t decompose inside.

• A small amount of green algae on hardscape is normal in closed systems.

Temperature

• Ideal: 60–75°F (typical indoor temperatures).

• Keep away from heaters, vents, drafts, and windows with direct sun.

Troubleshooting Tips

My moss is turning brown

• Too much light or heat → move to indirect light.

• Too dry → add one light mist of water.

Mold is growing in my terrarium.

• Mold happens in closed ecosystems that are too damp -- no worries!

• Remove the lid for 12–24 hours and gently remove white fuzz.

• Increase future venting, especially with acrylic lids.

• For larger terrariums, you may wish to add springtails, which are very small housekeeping beneficial bugs (don't worry, they won't leave the terrarium). They will eat any mold and other rotting materials, keeping your terrarium in balance long-term.

I can't see the plants; there is too much condensation

• Vent for 3–6 hours until the glass clears.

• Repeat as needed.

💚 Enjoy Your Moss Terrarium!