---
title: Cushion moss in a terrarium | Glass Jar Garden
description: Cushion moss (Leucobryum glaucum): Plump pale cushions that go grey when dry and green when wet. Needs light 1,500 to 10,000 lux, humidity 60 to 95 % RH,...
url: https://glassjar.garden/guide/moss/leucobryum-glaucum/
---

Moss

# Cushion moss
Leucobryum glaucum

Moderate · Fine in a closed jar

Plump pale cushions that go grey when dry and green when wet.

## What the simulation uses

- Light: 1,500 to 10,000 lux (The brightness it grows well in.)

- Humidity: 60 to 95 % RH (Air moisture it is happy in; below the lower end it dries out.)

- Temperature: 10 to 24 °C (Comfortable range; outside it growth slows.)

- Dies at: below -5 or above 44 °C (Days beyond these temperatures kill it.)

- Soil pH: 3.8 to 5 pH (Soil acidity it prefers.)

- Grows up: 0.08 cm/month (How fast it gains height in good conditions.)

- Spreads: 0.05 cm/month (How fast its edge creeps outwards.)

- Thickens: 1.25 %/month (How fast its cover fills in on its own ground.)

- Copes with wet: fair (How well it stands soggy soil; poor means rot comes quickly.)

- Copes with still air: fair (Sealed jars have still air; poor means grey mould finds it.)

- Copes with shade: good (How well it holds on in dim light.)

- Copes with drying: good (How well it survives the jar drying out.)

- Water use: 0.03 ml/cm²/day (Water that evaporates off the cushion each day in room air.)

- Holds water: 0.3 ml/cm² (Water a cm² of moss soaks up and keeps.)

- Grows on: soil, stone (Where it can take hold and spread. Moss that cannot grow on stone thins out there.)

## Care

- Day length: 10 to 14 h

- Substrate: Moist

## What kills it

- waterlogged substrate
- lime/calcareous water
- a sealed jar left soaking: fog on the glass all day, never vented
- hard frost when dry

## Description
Cushions can grow 3 to 20 cm tall, and a torn one is slow to regrow, so handle it gently. It hates waterlogged soil, limy water and a sealed jar that drips with constant condensation. Give it some air movement and keep lime away.

Also called pincushion moss, pillow moss, large white-moss, bun moss (UK trade).

Estimated, where sources were thin: photoperiod_h; humidity_rh_pct; temp_lethal_c.max; coverage_pct_per_month.

## Sources

- [nora.nerc.ac.uk/id/eprint/1131/1/BRYOATT.pdf](https://nora.nerc.ac.uk/id/eprint/1131/1/BRYOATT.pdf)
- [digitalcommons.mtu.edu/cgi/viewcontent.cgi?article=1066&context=bryo-ecol-subchapters](https://digitalcommons.mtu.edu/cgi/viewcontent.cgi?article=1066&context=bryo-ecol-subchapters)
- [digitalcommons.mtu.edu/cgi/viewcontent.cgi?article=1060&context=bryo-ecol-subchapters](https://digitalcommons.mtu.edu/cgi/viewcontent.cgi?article=1060&context=bryo-ecol-subchapters)
- [ohiomosslichen.org/moss-leucobryum-glaucum](https://www.ohiomosslichen.org/moss-leucobryum-glaucum/)
- [en.wikipedia.org/wiki/Leucobryum_glaucum](https://en.wikipedia.org/wiki/Leucobryum_glaucum)

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

[Common smoothcap](https://glassjar.garden/guide/moss/atrichum-undulatum/) · [Dotted thyme-moss](https://glassjar.garden/guide/moss/rhizomnium-punctatum/) · [All moss](https://glassjar.garden/guide/moss/)