A closed terrarium is a self-sustaining ecosystem that mimics nature in a small, enclosed environment. These beautiful glass gardens are low-maintenance, making them perfect for those who love plants but want an easy-care setup.
In this guide, you’ll learn everything you need to know about keeping your closed terrarium healthy, from watering and light requirements to troubleshooting common problems.
🌞 Light Requirements: Finding the Perfect Spot
Since closed terrariums trap moisture, they work best with tropical plants that love humidity. However, too much direct sunlight can overheat the container, causing condensation buildup and plant damage.
Best Light Conditions for Closed Terrariums
✔ Bright, indirect sunlight (near a north- or east-facing window).
✔ Artificial light or grow lights can supplement natural light.
✔ Avoid direct sun exposure, which can cause overheating and burn the plants.
Signs of Too Much or Too Little Light
🔹 Too much light → Excess condensation, yellowing leaves, or heat stress.
🔹 Too little light → Plants become pale, leggy, and lose their compact shape.
Solution:
• If your terrarium overheats, move it away from direct sunlight or place it in a shaded area.
• If plants become leggy, move the terrarium to a brighter location.
💧 Watering: How to Maintain the Perfect Moisture Level
One of the best parts about a closed terrarium is that it requires very little watering! Since it’s a sealed environment, water continuously recycles itself through condensation and evaporation.
How to Water a Closed Terrarium
✔ Water sparingly! Once sealed, a terrarium should rarely need watering.
✔ If your terrarium looks dry, add a small amount of water using a misting bottle or a dropper. For larger terrariums, pour just a few ounces.
✔ Always check the condensation levels inside the glass to determine if watering is needed.
Signs of Overwatering & Underwatering
🔹 Too much water → Constant condensation, mold growth, or rotting plants.
🔹 Too little water → Soil looks dry, leaves become droopy or crispy.
Solution:
• If your terrarium is too wet, open the lid and let excess moisture evaporate for a few hours before resealing.
• If it’s too dry, mist lightly and monitor moisture levels over the next few days.
🌡️ Temperature & Humidity: Creating the Ideal Environment
Closed terrariums create a humid microclimate, perfect for tropical plants like ferns, mosses, and fittonias.
Best Temperature & Humidity Levels
✔ Temperature: 65-80°F (18-27°C) is ideal.
✔ Humidity: 60%+ for moisture-loving plants.
✔ Avoid placing near heaters, radiators, or air conditioners, which can disrupt humidity levels.
Managing Condensation
• Too much condensation? Wipe down excess moisture and leave the lid open for an hour.
• Too little condensation? Lightly mist the inside of the glass and observe over the next few days.
🍃 General Maintenance: Keeping Your Terrarium Thriving
Closed terrariums require very little upkeep, but occasional maintenance ensures they stay healthy.
✔ Trim overgrown plants to prevent crowding.
✔ Remove dead or decaying leaves to avoid mold.
✔ Wipe the glass regularly to keep it clear and free of moisture buildup.
✔ Rotate your terrarium occasionally to ensure even light distribution.
🛑 Common Problems & Solutions
1. Why Is My Terrarium Fogging Up Too Much?
🔹 Problem: Excess humidity inside the glass.
✅ Solution: Open the lid for an hour to allow excess moisture to escape.
2. Why Are My Plants Turning Yellow or Rotting?
🔹 Problem: Overwatering or poor airflow.
✅ Solution: Remove any rotting leaves, let the terrarium dry out, and water less frequently.
3. Why Is There Mold Growing in My Terrarium?
🔹 Problem: Poor air circulation and too much moisture.
✅ Solution: Improve ventilation by airing it out occasionally, and remove mold with a Q-tip dipped in diluted hydrogen peroxide.
4. Why Are My Plants Growing Too Tall?
🔹 Problem: Not enough light, causing plants to stretch.
✅ Solution: Move to brighter, indirect light and prune overgrown stems.
📌 Closed Terrarium FAQ
How often should I water my closed terrarium?
Water only when necessary—typically every 1-2 months if condensation levels drop.
Can I use succulents in a closed terrarium?
No, succulents prefer dry environments, while closed terrariums trap humidity. Instead, use tropical plants like ferns, moss, and fittonias.
How long do closed terrariums last?
With proper care, a closed terrarium can last years, with some ecosystems surviving decades!
Do I need to fertilize my closed terrarium?
Fertilizing isn’t necessary, but if desired, use a diluted liquid fertilizer once every 6 months.
Can I open my terrarium?
Yes! Occasionally opening your terrarium helps regulate moisture and provides fresh air.
🌿 Final Thoughts: Let Nature Do the Work!
A closed terrarium is a self-sustaining mini ecosystem that requires minimal effort to maintain. By providing the right light, moisture, and airflow, your terrarium will flourish with little upkeep.
Observe your plants, make small adjustments when needed, and enjoy your thriving indoor jungle! 🌱💚