---
title: Knight's plume moss in a terrarium | Glass Jar Garden
description: Knight's plume moss (Ptilium crista-castrensis): Neat ostrich-feather fronds from conifer forest floors. Needs light 1,500 to 10,000 lux, humidity 70 to 100...
url: https://glassjar.garden/guide/moss/ptilium-crista-castrensis/
---

Moss

# Knight's plume moss
Ptilium crista-castrensis

Demanding · Fine in a closed jar

Neat ostrich-feather fronds from conifer forest floors.

## What the simulation uses

- Light: 1,500 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: 5 to 22 °C (Comfortable range; outside it growth slows.)

- Dies at: below -30 or above 42 °C (Days beyond these temperatures kill it.)

- Soil pH: 4 to 5.5 pH (Soil acidity it prefers.)

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

- Spreads: 0.13 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: 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

- warm tanks above ~25 C
- drying
- lime

## Description
It carpets the floors of northern conifer forests in acid, humid, half-shaded spots. Warm tanks above about 25 °C, drying and lime are all fatal. It is one of the harder mosses, best for a cool, humid jar.

Also called ostrich-plume feathermoss, plume moss.

Estimated, where sources were thin: growth rate; temp_c.

## Sources

- [en.wikipedia.org/wiki/Ptilium_crista-castrensis](https://en.wikipedia.org/wiki/Ptilium_crista-castrensis)
- [ohiomosslichen.org/moss-ptilium-crista-castrensis](https://www.ohiomosslichen.org/moss-ptilium-crista-castrensis/)
- [nora.nerc.ac.uk/id/eprint/1131/1/BRYOATT.pdf](https://nora.nerc.ac.uk/id/eprint/1131/1/BRYOATT.pdf)

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

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