Plant terrariums are tiny, self-contained ecosystems that bring a bit of nature indoors. They’re beautiful, calming, and surprisingly low-maintenance, if you care for them correctly. Whether you’ve just built your first terrarium or received one as a gift, this guide will walk you through everything you need to know to keep it healthy and thriving.

What Is a Terrarium?

A terrarium is a small garden grown inside a clear container, usually made of glass. There are two main types:

• Closed terrariums – Sealed containers that recycle moisture through condensation, ideal for humidity-loving plants like mosses and ferns.
• Open terrariums – Containers with an opening, better suited for plants that prefer airflow and drier conditions, such as succulents and cacti.

Understanding which type you have is the first step to proper care.

Light: Bright but Indirect

Most terrarium plants thrive in bright, indirect light.

• Place your terrarium near a window with filtered sunlight.
• Avoid direct sun, which can overheat the glass and scorch plants.
• If natural light is limited, a grow light placed a few feet away works well.

A good rule of thumb: if it’s comfortable for your eyes, it’s probably comfortable for your terrarium.

Watering: Less Is More

Overwatering is the most common cause of terrarium problems.

• Closed terrariums may only need water every few months. If you see heavy condensation all day, it’s likely too wet.
• Open terrariums need occasional watering, but the soil should dry slightly between waterings.

Tips:

• Use a spray bottle or small spoon for control.
• Water the soil, not the leaves
• If water pools at the bottom, you’ve added too much.

Airflow and Maintenance

Even sealed terrariums benefit from occasional fresh air.

• Open closed terrariums for a few hours every few weeks to prevent mold.
• Trim overgrown plants to maintain balance and visibility.
• Remove any dead or yellowing leaves promptly.

A little upkeep goes a long way in keeping the ecosystem healthy.

Common Problems (and How to Fix Them)

• Foggy glass all day: Too much moisture → air it out and reduce watering.
• Wilting or browning plants: Could be too much sun or too little water.
• Mold Growth: Improve airflow and remove affected areas immediately.

Terrariums are forgiving. Most issues can be corrected if caught early.

Final Thoughts

Caring for a terrarium is about balance: light but not too much, water but not too often, and occasional attention without overhandling. With the right conditions, your terrarium can thrive for years, offering a small, peaceful window into nature.

Treat it like a tiny world, and enjoy watching it grow.