Effective: 6 September 2026
Under Glass is beginner terrarium knowledge for UK rooms. It is not a substitute for a horticulturist, a pest-control professional, a doctor, or a solicitor. Read it as a careful friend with a pipette, not as a guarantee.
Jars fail
Closed cases rot, dry out, cook on a south sill, and grow mould. A guide can be right in general and still wrong for your lid, your tap water, or a plant that was already sick. Change one thing, then wait. If a jar smells sour or plants are mush, take the lid off. Rebuilding a small jar is cheaper than pouring chemicals through it.
Plants, pests and people
Some houseplants are harmful if eaten. Keep jars away from pets and small children who chew leaves. We do not list every toxic species. Check a plant before you bring it indoors if that matters in your home.
Pesticides, hydrogen peroxide, and “nuke the jar” tricks can hurt moss, ferns, springtails and you. We prefer mechanical removal, venting, and patience. If you use a product, you follow its label — not a sentence on this website.
People who react to mould should not lean into a badly affected jar. Open it outdoors or bin it if you need to.
Names and “baby tears”
Shop labels lie. “Baby tears” may mean Soleirolia or a pilea. Our first jar means Pilea depressa unless a page says otherwise. If you are unsure, wait and write to us rather than sealing a mystery plant.
Wild collecting
Do not assume moss, wood or stone from a verge or a wood is legal or clean to put in a sealed case. Prefer cultivated plants. We are not giving foraging or wildlife advice.
Media
Photographs and clips are teaching aids. Lighting, timing and glass are simplified. A caption is not a laboratory protocol.
Money
There is no shop on Under Glass today. If a guide later mentions a tool or a bag of mix with an affiliate link, that page should say so in plain language. No manufacturer pays for placement as things stand.
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Nothing on this page excludes liability that UK law does not allow us to exclude.