Terrarium knowledge for beginners
Learn to create thriving miniature worlds
Under Glass is a calm, beautiful library for how terrariums work — choosing cases, mixing substrates, picking plants and fauna, and keeping tiny ecosystems healthy.
Photo by Annie Spratt on Unsplash
Build this weekend
Your first closed jar
One sealed jar, a tropical mix, three humidity lovers, then wait before adding springtails. Arid bowls are the other path.
First jar · 1/6
Climate
Begin with a sealed humid climate. Succulents are the other path — not this jar.
Core learning areas
Everything a first terrarium needs
Cases
Closed, open, and in-between — choose a climate that fits your plants.
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Substrates
Mixes that hold moisture without drowning roots, with a live mixer.
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Plants
Beginner-friendly species with light, humidity, and companion notes.
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Fauna
Springtails, isopods, and other helpers for living miniature ecosystems.
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Guides
Step-by-step lessons from first jar to troubleshooting calm fixes.
ExploreFeatured guides
Start reading
Matching Plants to One Climate
A terrarium succeeds when every plant wants the same light, humidity and airflow — not when the jar looks like a gift-shop sampler of opposites.
9 min read
Cycling and Venting a New Closed Case
The first fortnight after sealing is a negotiation with moisture and microbes — how to vent on purpose, read condensation, and introduce cleanup crew without panicking at every white speck.
9 min read
Mould vs Mycelium: How to Tell What You’re Seeing
Fuzzy panic vs fine white threads: how beginners can distinguish nuisance mould from useful saprotrophic mycelium, and what to do without nuking the ecosystem.
9 min read
Troubleshooting Common Issues
Mould, yellow leaves, collapsed moss — calm fixes first.
10 min read
Substrate Basics
Air, water, and structure — the three jobs of a good mix.
9 min read
Adding Springtails
Why microfauna are the friendliest bioactive upgrade.
7 min read
A note on the name
Inspired by a sealed bottle
In Victorian London, Nathaniel Bagshaw Ward watched a fern thrive inside a closed glass bottle — light in, soot out, water beading and running back down. That small weather cycle is the ancestor of the closed jar.
Under Glass is named for that way of keeping life: a calm beginner library for the climate inside the glass, not a shop for antique cases.
Read the short history
Suggested first case
Closed Jar
Sealed glass with a stable humid climate — ideal first ecosystem.
Open case guidePhoto by Francesco Gallarotti on Unsplash