---
title: Activated charcoal in a terrarium | Glass Jar Garden
description: Activated charcoal: Small black porous chips that keep water sweet. A filter layer. In the jar it has holds water 30 % by volume, pore space 77.5 % by...
url: https://glassjar.garden/guide/soils/activated-charcoal/
---

Soils and layers

# Activated charcoal

Small black porous chips that keep water sweet. A filter layer.

## What the simulation uses

- Holds water: 30 % by volume (Water it keeps after draining; the rest runs down to the drainage.)

- Pore space: 77.5 % by volume (Room for air and water between grains; low means roots suffocate when wet.)

- Weight: 450 g/L (How heavy a litre is.)

- pH: 7 to 10 pH (How acid it keeps the soil.)

- Mould risk: none (How much fresh food it gives white mould; high-risk soils fuzz over in the first weeks.)

- Nutrients: none (Plant food it brings.)

- Presses down to: 97 % of its loose depth (How far pressing can pack it, keeping its weight.)

## Description
Each tiny chip is riddled with pores that trap dissolved waste and smells. It works for months, then quietly fills up and stops filtering. Use a thin layer or mix it through the soil.

Also called activated carbon.

Estimated, where sources were thin: porosity, water holding and pH not on cited pages; adsorption capacity in a terrarium unquantified.

## Sources

- [en.wikipedia.org/wiki/Activated_carbon](https://en.wikipedia.org/wiki/Activated_carbon)
- [en.wikipedia.org/wiki/Biochar](https://en.wikipedia.org/wiki/Biochar)

[Grow it in a jar](https://glassjar.garden/?guide=soils/activated-charcoal)

[ABG mix](https://glassjar.garden/guide/soils/abg-mix/) · [Akadama](https://glassjar.garden/guide/soils/akadama/) · [All soils and layers](https://glassjar.garden/guide/soils/)