---
title: Terrarium guide | Glass Jar Garden
description: How a sealed terrarium works, and an encyclopedia of terrarium plants, mosses, springtails, isopods, soils, stones and moulds, with the numbers behind each.
url: https://glassjar.garden/guide/
---

Guide

# The terrarium guide

How a sealed jar keeps itself alive, and everything you can put in one, with the numbers the simulator runs on.

## Basics

- [The jar: A sealed jar waters itself: plants breathe water out, it beads on the glass and runs back down.](https://glassjar.garden/guide/basics/the-jar/)
- [Layers: Bottom to top: drainage, a barrier, soil, then a top dressing.](https://glassjar.garden/guide/basics/layers/)
- [Plants: Small, slow and alike in what they want.](https://glassjar.garden/guide/basics/plants/)
- [Moss: No roots: moss drinks from the air and the surface it sits on.](https://glassjar.garden/guide/basics/moss/)
- [Cleanup crew: Tiny animals that keep a jar from rotting.](https://glassjar.garden/guide/basics/cleanup-crew/)

## How it works

- [Needs and health: Each day every living thing scores its needs; health follows the score.](https://glassjar.garden/guide/how-it-works/needs-and-health/)
- [Death and hazards: Only hazards kill, each rising from zero at its threshold.](https://glassjar.garden/guide/how-it-works/death-and-hazards/)
- [Soil: Layers drain, hold water, feed plants and set the pH the roots feel.](https://glassjar.garden/guide/how-it-works/soil/)
- [Water: Soil fills to what it can hold; the rest drains to the drainage layer.](https://glassjar.garden/guide/how-it-works/water/)
- [Humidity and the lid: Sealed jars keep every drop; open jars lose water to the room.](https://glassjar.garden/guide/how-it-works/humidity-and-the-lid/)
- [Light: The day's light, brightness times hours, drives growth.](https://glassjar.garden/guide/how-it-works/light/)
- [Temperature: The jar follows the room, a little warmer under a lamp.](https://glassjar.garden/guide/how-it-works/temperature/)
- [Plants: Plants grow on light and food, share space, and stop at the lid.](https://glassjar.garden/guide/how-it-works/plants/)
- [Moss: Moss creeps from its edges in damp air and browns back when dry.](https://glassjar.garden/guide/how-it-works/moss/)
- [Critters: Each crew is a colony that grows to what the jar can feed.](https://glassjar.garden/guide/how-it-works/critters/)
- [Mould: White mould blooms on fresh organics and leaves; springtails eat it.](https://glassjar.garden/guide/how-it-works/mould/)
- [Care: Mist, water, vent and tidy, by hand or on a routine.](https://glassjar.garden/guide/how-it-works/care/)
- [Chance and forecasts: Two things are random; everything else repeats exactly.](https://glassjar.garden/guide/how-it-works/chance-and-forecasts/)
- [Checked against real jars: Fourteen jars their owners described online, rebuilt and run: all fourteen turn out the way the real ones did.](https://glassjar.garden/guide/how-it-works/checked-against-real-jars/)

## Starter jars

- [Terrarium ideas: 26 starter jars, easy to hard: every layer, plant and moss, and a link to open each in the simulator.](https://glassjar.garden/starter-jars/)

## Encyclopedia

- [Plants: Every plant you can grow, with the light, humidity, temperature and soil it needs, and what kills it. 49 entries.](https://glassjar.garden/guide/plants/)
- [Moss: Carpet, cushion and aquarium mosses: how fast they spread, where they grow, and the air they need. 31 entries.](https://glassjar.garden/guide/moss/)
- [Critters: The cleanup crew: springtails, isopods, worms and snails, what they eat and how big a colony a jar can feed. 10 entries.](https://glassjar.garden/guide/critters/)
- [Soils and layers: Drainage, filters, soils and top dressings: how much water each holds, its pH, and how fast it rots down. 41 entries.](https://glassjar.garden/guide/soils/)
- [Stones and wood: Stones and wood for the scene, and which mosses can climb them. 32 entries.](https://glassjar.garden/guide/hardscape/)
- [Moulds and films: The fuzz, films and diseases a jar can grow, what sets them off and what keeps them down. 10 entries.](https://glassjar.garden/guide/moulds/)