---
title: Terrarium simulator and builder | Glass Jar Garden
description: Build a terrarium online: pour the layers, plant real species, seal the jar and watch it live day by day. A free terrarium simulator and builder in your browser.
url: https://glassjar.garden/terrarium-simulator/
---

Free, in your browser

# Terrarium simulator

Glass Jar Garden is a terrarium simulator and builder that runs in your browser. Build a jar layer by layer, plant real species, seal it, and watch it live: the water cycling, moss creeping, plants growing, and mould when something is off.

[Open the simulator](https://glassjar.garden/)

## Build it like a real one

- Pour drainage, a barrier, soil and a top dressing from a scoop; shape the ground with a brush.
- Plant from 49 real plants and 31 mosses, set stones and wood, and add springtails and isopods.
- Water by the millilitre, choose the light, the room and a care routine.
- Round jars, bottles and cloches fill along their curved glass.

## Then it lives

Seal it, or leave it open, and every day the simulation works out the water in each layer, the humidity under the lid, the light each plant gets and its health. Before you seal, a one-year forecast says what should still be alive. [How it works](https://glassjar.garden/guide/how-it-works/) has every mechanism and the numbers it runs on.

## A terrarium game, and a planner

It plays like a calm building game: no score, no timer, nothing to unlock. Jars keep living while you are away and catch up when you come back. It is also a planner: try a build before buying anything, then follow its recipe.

## Start from a ready jar

- [Beginner jar easy](https://glassjar.garden/starter-jars/beginner-jar/)
- [Moss jar easy](https://glassjar.garden/starter-jars/moss-jar/)
- [Paludarium lite hard](https://glassjar.garden/starter-jars/paludarium-lite/)
- [Carnivore bog medium](https://glassjar.garden/starter-jars/carnivore-bog/)
- [Desert bowl easy](https://glassjar.garden/starter-jars/desert-bowl/)
- [Cloche garden easy](https://glassjar.garden/starter-jars/cloche-garden/)
- [Wardian case medium](https://glassjar.garden/starter-jars/wardian-case/)
- [Mini forest medium](https://glassjar.garden/starter-jars/mini-forest/)

[All 26 starter jars](https://glassjar.garden/starter-jars/)

## Questions

- Is it free?: Yes. It runs in your browser, with no account and nothing to install.
- Does it work on a phone?: Yes, on any recent phone or computer with a browser that supports WebGL.
- Is the simulation realistic?: It runs day by day on real species data, and 14 real jars described by their owners were rebuilt in it: all 14 turned out the way the real ones did.
- Can I share my terrarium?: Yes. A share link shows the jar as it is now, still living, and you can record a timelapse of its whole life or take photos.
- Can I use it to plan a real terrarium?: Yes. Every starter jar has a recipe page with the glass, each layer, plant and moss, and the water and light to give it.

[Build a terrarium](https://glassjar.garden/)

Interested in the science? Read about the [closed ecosystem](https://glassjar.garden/ecosystem-simulator/) it simulates.