---
title: Terrarium drainage: LECA vs gravel vs lava rock
description: LECA, gravel, lava rock and 6 more drainage materials compared: how much water each holds, its weight, and how long it lasts in a terrarium.
url: https://glassjar.garden/guide/drainage-leca-vs-gravel/
---

Guide

# Terrarium drainage: LECA vs gravel vs lava rock

The drainage layer catches spare water below the roots, so the soil never sits in it. What matters is how much space it leaves for water, how heavy it is, and whether it breaks down.

MaterialHolds waterPore spaceWeightBreaks down in[Aquarium gravel](https://glassjar.garden/guide/soils/aquarium-gravel/)7.5 % by volume40 % by volume1500 g/Ldoes not[Decomposed granite](https://glassjar.garden/guide/soils/decomposed-granite/)11.5 % by volume35 % by volume1650 g/Ldoes not[Fine clay pebbles](https://glassjar.garden/guide/soils/clay-pebbles-fine/)16 % by volume80 % by volume400 g/Ldoes not[Lava rock (scoria)](https://glassjar.garden/guide/soils/lava-rock/)17.5 % by volume55 % by volume900 g/Ldoes not[LECA (expanded clay)](https://glassjar.garden/guide/soils/leca/)14 % by volume80 % by volume380 g/Ldoes not[Pea gravel](https://glassjar.garden/guide/soils/pea-gravel/)5 % by volume40 % by volume1450 g/Ldoes not[Perlite](https://glassjar.garden/guide/soils/perlite/)25 % by volume85 % by volume90 g/Ldoes not[Pumice](https://glassjar.garden/guide/soils/pumice/)27.5 % by volume74.5 % by volume560 g/Ldoes not[River pebbles](https://glassjar.garden/guide/soils/river-pebbles/)3 % by volume40 % by volume1500 g/Ldoes not

LECA is light and holds water in its pores, which helps a jar recover from overwatering; gravel is cheap and heavy; lava rock sits between the two. Any of them needs a barrier on top so soil does not wash down.

- Layers go in damp, at about three quarters of what they hold.
- Gravel, LECA or lava rock under the soil catches excess water below the roots.
- Water wicks up from a wet drainage layer, and sideways into drier soil.

[Pour a drainage layer](https://glassjar.garden/)

## More terrarium guides

- [Closed vs open terrarium: Which to build, and which plants suit each.](https://glassjar.garden/guide/closed-vs-open-terrarium/)
- [Best plants for a closed terrarium: Plants that live sealed, easiest first.](https://glassjar.garden/guide/best-plants-for-closed-terrarium/)
- [Best moss for a terrarium: Mosses for closed and open jars, and what they grow on.](https://glassjar.garden/guide/best-moss-for-terrarium/)
- [Terrarium layers explained: Drainage, barrier, soil and top dressing, and what each does.](https://glassjar.garden/guide/terrarium-layers/)
- [Mould in a terrarium: Why new jars fuzz, which mould matters, and how to stop it.](https://glassjar.garden/guide/terrarium-mould/)
- [Springtails vs isopods: The cleanup crew compared: what each eats and where it lives.](https://glassjar.garden/guide/springtails-vs-isopods/)