---
title: Fern moss in a terrarium | Glass Jar Garden
description: Fern moss (Thuidium delicatulum): Fine, fern-like fronds in loose spreading carpets. Needs light 1,000 to 10,000 lux, humidity 70 to 100 % RH, temperature 8...
url: https://glassjar.garden/guide/moss/thuidium-delicatulum/
---

Moss

# Fern moss
Thuidium delicatulum

Easy · Fine in a closed jar

Fine, fern-like fronds in loose spreading carpets.

## What the simulation uses

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

- Humidity: 70 to 100 % RH (Air moisture it is happy in; below the lower end it dries out.)

- Temperature: 8 to 24 °C (Comfortable range; outside it growth slows.)

- Dies at: below -25 or above 42 °C (Days beyond these temperatures kill it.)

- Soil pH: 5 to 6.5 pH (Soil acidity it prefers.)

- Grows up: 0.04 cm/month (How fast it gains height in good conditions.)

- Spreads: 0.2 cm/month (How fast its edge creeps outwards.)

- Thickens: 3 %/month (How fast its cover fills in on its own ground.)

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

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

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

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

- Water use: 0.04 ml/cm²/day (Water that evaporates off the cushion each day in room air.)

- Holds water: 0.22 ml/cm² (Water a cm² of moss soaks up and keeps.)

- Grows on: soil, wood (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

- drying out
- burial by leaf litter

## Description
It grows on moist, shaded ground, logs and rocks. Keep it from drying out, and clear away fallen leaves before they bury it.

Also called delicate fern moss, common fern moss.

Estimated, where sources were thin: growth rate; temp ranges.

## Sources

- [nora.nerc.ac.uk/id/eprint/1131/1/BRYOATT.pdf](https://nora.nerc.ac.uk/id/eprint/1131/1/BRYOATT.pdf)
- [ohiomosslichen.org/moss-thuidium-delicatulum](https://www.ohiomosslichen.org/moss-thuidium-delicatulum/)
- [en.wikipedia.org/wiki/Thuidium_delicatulum](https://en.wikipedia.org/wiki/Thuidium_delicatulum)
- [digitalcommons.mtu.edu/cgi/viewcontent.cgi?article=1054&context=bryo-ecol-subchapters](https://digitalcommons.mtu.edu/cgi/viewcontent.cgi?article=1054&context=bryo-ecol-subchapters)

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

[Dotted thyme-moss](https://glassjar.garden/guide/moss/rhizomnium-punctatum/) · [Fire moss](https://glassjar.garden/guide/moss/ceratodon-purpureus/) · [All moss](https://glassjar.garden/guide/moss/)