Closed or open terrarium: which lid should you use
Updated: 21 October 2026
You have seen one amazon.co.uk title list ferns, moss, succulents and cacti in the same sentence, and you need to decide whether the lid stays shut. A closed or open terrarium is two climates, and a swing roof sits between them. The containers and prices are on the [glass terrarium comparison](/hub/houseplants/glass-terrarium). Peter F. used the Royal Horticultural Society, Kew and BBC Gardeners’ World for the plant split. The leak notes are UK reviews from the 19 October 2026 capture, not a lab seal test. A qualifying purchase can earn us a commission at no extra cost to you.
You have seen one amazon.co.uk title list ferns, moss, succulents and cacti in the same sentence, and you need to decide whether the lid stays shut.
You have seen one amazon.co.uk title list ferns, moss, succulents and cacti in the same sentence, and you need to decide whether the lid stays shut. A closed or open terrarium is two climates, and a swing roof sits between them. The containers and prices are on the glass terrarium comparison. Peter F. used the Royal Horticultural Society, Kew and BBC Gardeners’ World for the plant split. The leak notes are UK reviews from the 19 October 2026 capture, not a lab seal test. A qualifying purchase can earn us a commission at no extra cost to you.
Our top picks
| Badge | Product | Closure | Opening | Water note | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  ZOOBAYA ZOOBAYA greenhouse | Lift-off hinged top; one vent | Hand-sized in reviews | UK reviews say it is not watertight | 7.4 | about £32.93 | View offer |
 Homtone Homtone house (23 cm) | Swing lid, can be propped | 12 × 9 cm | No watertight claim; slight leak in reviews | 8.1 | about £29.95 | View offer | |
| Alternative |  SUPVOX SUPVOX corked jar | Cork with a ventilation hole | Wide mouth claimed; centimetres n/a | Single-piece jar; no soldered frame | 4.7 | about £18.87 | View offer |
On this page
Two climates, one title
A bullet that names succulents, cacti, ferns, moss and a Venus flytrap is a search list, not a planting plan. The Royal Horticultural Society puts small ferns, fittonia, peperomia and moss in sealed glass, and succulents and cacti in open glass. Kew leaves cacti and succulents in the open, with echeveria as one example. If you shut the lid on both groups, the succulents sit in the humidity the ferns want and soften after a few weeks. If you leave the lid off a fittonia in a dry heated room, the leaves crisp. Choose the plants, then set the lid. Compost and the winter rest for succulents are on the succulent glass terrarium page.
When the lid stays shut
Shut the lid for small ferns, fittonia, peperomia, pilea, hypoestes and moss. A closed terrarium that still shows condensation only needs water a few times a year. Do not put a sealed jar in summer sun, or the glass cooks the plants. Gardeners’ World suggests about 1 metre from a north window, about 3 metres from an east or west window, and about 5 metres from a south window. Moisture on about a third of the jar can be left alone. Heavier fog should be wiped and the lid aired. Kew is blunter: fog means too wet, so open the jar for a few hours. A cork with a hole needs water a little more often than a true seal.
When the lid stays open
Leave the lid off, or propped, for succulents and cacti. The RHS succulent guide is to water when the surface is dry in the growing season, and barely at all from November to early March. Rainwater is preferred, because tap water leaves chalk on the leaves. Gardeners’ World’s dessertspoon-a-week line from March to October is a rule of thumb. When it conflicts with the RHS, check the compost surface rather than the calendar. An open geometric still needs a tray if UK reviews say the seams weep. Do not pour a reservoir for the week.
A swing lid is not a corked jar
Several houses look closed in the photograph and do not seal. Homtone’s swing lid can be propped, and UK reviews mention a support plus a slight leak. LIMOR’s drain hole shows up as water in the drip tray. The ZOOBAYA houses use a lift-off top, and UK reviews describe leaks, including water on a shelf. One greenhouse review kept succulents by leaving the roof open. SUPVOX is a cork with a ventilation hole: not a full seal, and not an open dish. Toyvian says both airtight jar and corked bottle, and airtight there is an untested bullet. PYEF does not name a lid type. If you want succulents, prop the Homtone or ZOOBAYA roof and do not push a cork home.
Common questions
How much condensation is enough?
Gardeners’ World’s rule of thumb is condensation on about a third of the jar. Heavier fog should be wiped and the lid aired. Almost no condensation on a closed planting means a small drink, not a flood. Kew says fog means too wet. These are guides, not a sensor reading. A soldered house that drips onto the table is a leak, not healthy condensation, and it needs a tray and less water.
Is a swing-lid house actually closed?
Often it is only closed in the photograph. Homtone and LIMOR can be propped open, and UK reviews describe slight leaks or water in a tray. The ZOOBAYA houses draw stronger leak complaints, including a shelf getting wet. Treat a swing roof as a door you can open, not as a sealed bottle. If moisture vanishes in an hour and the tray is wet, the frame is open whether you wanted that or not.
Where do I put each type in a UK room?
Gardeners’ World places a closed terrarium about 1 metre from a north window, 3 metres from east or west, and 5 metres from south, in bright indirect light rather than summer sun. An open succulent planting wants a brighter sill, which is the RHS succulent guide, not the closed-jar distances. Do not average those two instructions. Match the distance to the lid you are actually using, and move the glass if it fogs solid or the leaves bleach.
What if the title lists succulents and ferns together?
Ignore the list as a recipe. Pick one climate. Ferns and moss can live with the lid shut if the container actually holds humidity. Succulents need the lid open and a gritty mix that dries. A Venus flytrap in the same bullet is a third plant with its own needs, and it is not a reason to buy the house. The seller is covering search terms. You still have to choose.
Does a cork with a hole count as closed?
Not fully. SUPVOX states a ventilation hole in the stopper, so some air moves even when the cork is in. The RHS says a small opening means you water a little more often than a true seal. Toyvian’s airtight line is untested in this file. A vented cork can still suit moss if condensation behaves, but it is a poor choice for a cactus, which wants a genuinely open top rather than a small leak of air.
Related pages
Sources
Public UK sources named below. amazon.co.uk prices, stars and review counts on these eight listings were read for this comparison. Page updated 21 October 2026.
- RHS, Terrariums and bottle gardens (retrieved 21.10.2026)
- BBC Gardeners’ World, terrarium care (retrieved 21.10.2026)
- Kew, Make your own terrarium (retrieved 21.10.2026)
- Wildlife and Countryside Act 1981, section 13 (retrieved 21.10.2026)
- Consumer Rights Act 2015, section 9 (retrieved 21.10.2026)
- Business Companion, Consumer Rights Act 2015 (retrieved 21.10.2026)
- GOV.UK, reporting product safety issues (retrieved 21.10.2026)
- Wildlife Trusts, sphagnum (retrieved 21.10.2026)