How many Levels of a Terrarium?

Terrariums usually have 3 to 5 basic levels (or layers), depending on how detailed you want to get. A basic terrarium usually includes:

1. Drainage Layer: Rocks, pebbles, or LECA (lightweight clay balls) to help excess water drain.
2. Barrier Layer: Mesh or activated charcoal to keep water clean and stop soil from mixing with drainage.
3. Substrate Layer: Soil or a soil mix that matches the needs of your plants or animals.
4. Plant Layer: Your plants or mosses (or hardscape like wood and rocks if it’s for reptiles).
5. Decoration/Top Layer (optional): Things like decorative stones, moss, figurines, or leaf litter.

Some people combine steps, but this is the full setup if you want a healthy, long-lasting terrarium.

Why put charcoal in a terrarium?

Activated charcoal serves several important functions in a terrarium:

1. Odor control – It absorbs and neutralizes unpleasant odors that might develop in the closed environment, especially in terrariums with high humidity.
2. Water purification – Charcoal helps filter the water as it passes through the terrarium system, removing impurities and preventing water stagnation.
3. Toxin absorption – It captures harmful chemicals, bacteria, and fungi that can build up in the soil over time, acting as a natural purifier.
4. Mold prevention – The antimicrobial properties of charcoal help prevent mold growth in the humid terrarium environment.
5. Root health – By reducing toxins and excess nutrients in the water, charcoal helps prevent root rot and promotes healthier plant growth.
6. Longevity – A charcoal layer extends the life of your terrarium by maintaining a cleaner, more balanced ecosystem that doesn’t need to be changed as frequently.

Typically, charcoal is added as part of the drainage layer or as a thin layer between the drainage and soil layers. While not absolutely mandatory, it’s highly recommended for closed terrariums where the ecosystem is more self-contained and would otherwise accumulate toxins over time.

Different Types of Terrariums