Guide
How to choose a terrarium plant
By Paul Reaney · Updated 5 July 2026
Not every houseplant belongs in a jar. Here are the nine things that actually decide whether a plant thrives in your terrarium — starting with the one that matters most.
1. Open or closed? (the make-or-break call)
This is the first thing to settle. A closed terrarium is a sealed jar or bottle that traps humidity — a warm, damp mini-rainforest. An open one is an unsealed bowl where air moves and moisture escapes. Humidity-lovers (ferns, moss, fittonia) thrive sealed; succulents, cacti and air plants need airflow and will rot in a closed jar. Get this wrong and nothing else matters.
2. Size and growth rate
Terrariums are tiny, so you want plants that are naturally small, small-leaved and slow-growing. The classic beginner mistake is pairing a vigorous grower with slow ones — the fast plant takes over. Think about the plant’s mature size, not how it looks in the shop.
3. Light
Most terrarium plants want bright, indirect light — an east or north window. Avoid direct sun: glass magnifies it and cooks the inside. A few ferns and mosses tolerate genuinely low light; succulents want the brightest spot you have.
4. Growth habit — where it sits in the scene
Shape decides placement. Low carpets and moss go in the foreground; accent plants like a nerve plant sit in the midground; taller plants and height go at the back, with trailing species cascading from the top. Mixing a carpet, a feature and a trailer gives a terrarium depth.
5. How fussy is it?
Some plants are nearly unkillable (pothos, moss, fittonia); others are lovely but demanding (maidenhair fern, rex begonia). If it’s your first build, weight the easy end.
6. Roots and substrate
Shallow-rooted, compact plants suit the limited soil depth of a terrarium. Pair them with a layered, free-draining substrate (drainage layer, then an airy mix) so water sits below the roots rather than around them.
7. Play nicely together
The golden rule: only combine plants that want the same light and moisture. Never mix a succulent with a fern — one wants dry and bright, the other humid and shaded, and one will always lose. Pick a “climate” for the vessel, then choose plants that share it.
8. Pets and safety
If you have curious cats, dogs or children, check toxicity before you buy. Fittonia, peperomia and many small ferns are pet-safe; some trailing favourites are not.
9. Temperature and availability
Most terrarium plants are tropical and happy at normal room temperature (18–24°C). And practically — is it small, affordable and easy to find as a young plant near you?
Ready to pick? Every plant in our directory is tagged by type and size, so you can filter to exactly what your terrarium needs.
Browse the plants →FAQ
What is the most important factor when choosing a terrarium plant?+
Whether it suits an open or closed terrarium. Humidity-loving plants thrive in sealed, closed terrariums, while succulents and cacti need the airflow of an open one and will rot if sealed in.
What are the easiest terrarium plants for beginners?+
Fittonia (nerve plant), moss, pothos and small ferns like the lemon button fern are forgiving, widely available, and thrive in closed setups. For open terrariums, haworthia and other hardy succulents are easiest.
Can you mix succulents and ferns in one terrarium?+
No. Succulents want dry, airy, bright conditions and ferns want constant humidity and shade. Combined in one vessel, one of them will always struggle — choose plants that share the same needs.