---
title: Sphagnum peat moss in a terrarium | Glass Jar Garden
description: Sphagnum peat moss: Dark, acid, spongy peat. Holds lots of water. In the jar it has holds water 65 % by volume, pore space 92.5 % by volume, weight 115 g/L.
url: https://glassjar.garden/guide/soils/peat-moss/
---

Soils and layers

# Sphagnum peat moss

Dark, acid, spongy peat. Holds lots of water.

## What the simulation uses

- Holds water: 65 % by volume (Water it keeps after draining; the rest runs down to the drainage.)

- Pore space: 92.5 % by volume (Room for air and water between grains; low means roots suffocate when wet.)

- Weight: 115 g/L (How heavy a litre is.)

- pH: 3.5 to 4.5 pH (How acid it keeps the soil.)

- Mould risk: low (How much fresh food it gives white mould; high-risk soils fuzz over in the first weeks.)

- Breaks down in: 5 to 15 years (How long it lasts before rotting down to fine soil.)

- Nutrients: low (Plant food it brings.)

- Presses down to: 40 % of its loose depth (How far pressing can pack it, keeping its weight.)

## Description
Partly decomposed sphagnum from bogs, very low in nutrients. Once bone dry it repels water, so moisten it well before use. Over the years it slowly compacts.

Also called peat, milled peat, sphagnum peat.

Estimated, where sources were thin: dry bulk density, porosity, AFP, CEC not from a fetched horticultural table (Bulk_density wiki: peat/organic soils 0.02-0.98 g/cm3).

## Sources

- [en.wikipedia.org/wiki/Peat](https://en.wikipedia.org/wiki/Peat)
- [en.wikipedia.org/wiki/Sphagnum](https://en.wikipedia.org/wiki/Sphagnum)
- [en.wikipedia.org/wiki/Potting_soil](https://en.wikipedia.org/wiki/Potting_soil)
- [engineeringtoolbox.com/density-materials-d_1652.html](https://www.engineeringtoolbox.com/density-materials-d_1652.html)

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

[Sphagnum barrier layer](https://glassjar.garden/guide/soils/sphagnum-barrier/) · [Substrate barrier mesh](https://glassjar.garden/guide/soils/mesh-barrier/) · [All soils and layers](https://glassjar.garden/guide/soils/)