---
title: Tree fern fibre in a terrarium | Glass Jar Garden
description: Tree fern fibre: Wiry dark fibre that roots and epiphytes love. In the jar it has holds water 35 % by volume, pore space 85 % by volume, weight 120 g/L.
url: https://glassjar.garden/guide/soils/tree-fern-fiber/
---

Soils and layers

# Tree fern fibre

Wiry dark fibre that roots and epiphytes love.

## What the simulation uses

- Holds water: 35 % by volume (Water it keeps after draining; the rest runs down to the drainage.)

- Pore space: 85 % by volume (Room for air and water between grains; low means roots suffocate when wet.)

- Weight: 120 g/L (How heavy a litre is.)

- pH: 4.5 to 6 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: 3 to 8 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
The wiry trunk and root mat of tree ferns, airy, slow to rot and a key part of ABG mix. Many tree ferns grow slowly and are threatened, so use it sparingly.

Also called hapu'u, xaxim, tree fern panel.

Estimated, where sources were thin: all physical numbers estimated; decay rate estimated (Pulu hairs crumble in a few years but trunk fibre lasts longer).

## Sources

- [en.wikipedia.org/wiki/Tree_fern](https://en.wikipedia.org/wiki/Tree_fern)
- [en.wikipedia.org/wiki/Pulu_(material)](https://en.wikipedia.org/wiki/Pulu_(material))
- [joshsfrogs.com/sp/abg-mix-4-quart-jf00504](https://joshsfrogs.com/sp/abg-mix-4-quart-jf00504)

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

[Topsoil](https://glassjar.garden/guide/soils/topsoil/) · [Vermiculite](https://glassjar.garden/guide/soils/vermiculite/) · [All soils and layers](https://glassjar.garden/guide/soils/)