🌿 Why Activated Charcoal Is a Must-Have for Your Terrarium

If you’ve ever had your terrarium smell a little funky or seen mold pop up, your setup might be missing a key component: activated charcoal. This powerful natural filter quietly works behind the scenes to keep your tiny world clean, fresh, and thriving.

🧪 What Does Activated Charcoal Actually Do?

In a closed terrarium (like those with a lid or minimal airflow), moisture builds up quickly—creating a perfect environment for bacteria, mold, and bad odors. Activated charcoal combats this by:

1. Filtering toxins from water that drains into the bottom layer
2. Neutralizing gases that can make your terrarium smell musty
3. Inhibiting mold and algae growth on substrate and wood
4. Balancing humidity by keeping water cleaner for longer

🪴 How to Use It in Your Setup

When layering your terrarium, the ideal sequence is:

1. Drainage layer (e.g. LECA or gravel)
2. Activated charcoal layer (1–2 cm thick)
3. Sphagnum moss (optional, acts as a filter barrier)
4. Terrarium soil mix
5. Plants and hardscape

You can use loose charcoal bits or powdered horticultural charcoal, but avoid using BBQ charcoal—it’s chemically treated and not safe for plants.

🧼 Maintenance Benefits

A terrarium with charcoal stays cleaner longer, reducing the need for substrate replacement and lowering the risk of root rot.