---
title: Soil: how the terrarium simulator works | Glass Jar Garden
description: Layers drain, hold water, feed plants and set the pH the roots feel. Roots judge the layer filling the top 5 cm: its pH and whether the species likes it. A...
url: https://glassjar.garden/guide/how-it-works/soil/
---

How it works

# Soil

Layers drain, hold water, feed plants and set the pH the roots feel.

- Roots judge the layer filling the top 5 cm: its pH and whether the species likes it.
- A thin top dressing does not change what the roots feel.
- Organic soil rots slowly, releasing the carbon and nitrogen growth runs on.
- Plain sand feeds little, so plants in it grow slowly.
- Pressing packs a layer down: fibres to 40% of their loose depth, soils 72%, sand 88%, gravel barely.

## Stats

- Root band: 5 cm

- Fresh organics rot: 2% a day at 20 °C

- Humus rots: 0.05% a day

- Fallen leaves rot: 3% a day

[See it in a jar](https://glassjar.garden/?guide=how-it-works/soil)

[← Death and hazards](https://glassjar.garden/guide/how-it-works/death-and-hazards/) · [Water →](https://glassjar.garden/guide/how-it-works/water/)