Terrarium plants: which ones should you choose, closed or open?

The best plants for a terrarium are low, dense, slow-growing plants, chosen according to the type of container: tropical plants that thrive in humid air (Fittonia, Peperomia, Pilea, Hypoestes, small ferns) for a closed terrarium, succulents and cacti only for an open terrarium. This guide helps you make this choice, plant by plant, with a large comparison table, and then build your terrarium step by step.

It does not cover adjusting humidity, which is already detailed in our guide to condensation in terrariums: read it once your plants are installed. Each plant mentioned links to its complete care sheet for more information.

🌟 Why the choice of plants determines the success of a terrarium

A successful terrarium depends first on the plants you put in it, much more than on the container. Under glass, the space is fixed: a plant that grows too quickly will touch the wall, suffocate its neighbors, and have to be removed. The RHS points out that many classic houseplants, even when young, become too vigorous for a terrarium over time.

The University of Missouri Extension recommends choosing low, dense plants and not mixing species with very different light and temperature requirements. Choosing well therefore means bringing together compatible, small, and patient plants.

📊 Which plant for which terrarium? The large comparison

Here are the most common terrarium plants, classified by container type, with their adult size and growth rate. The dimensions come from the NC State Extension (North Carolina State University), converted from inches to centimeters and rounded; the RHS lists Peperomia, Fittonia, Hypoestes, Pilea, small ferns, Cryptanthus, and Selaginella kraussiana as closed terrarium plants.

For the plants we have care sheets for, the link will take you to their complete guide.

📋 Quick technical sheet

Common guidelines for any plant terrarium, before choosing the species.

🪏 How to make a terrarium step by step

To make a terrarium, choose a clear glass container, place a reserve of washed gravel, a thin layer of charcoal for the closed version, and suitable potting mix, then plant from largest to smallest, cover with moss, and barely water before closing. The University of Florida Extension (UF IFAS) recommends 1.3 to 3.8 cm of gravel, charcoal for closed terrariums, and sterilized potting mix filling about 1/5 of the container.

The RHS recommends washed gravel at the bottom and potting mix mixed with a draining material, in a ratio of about 4 to 1.

Warning: a jar has no hole, so this layer does not drain anything outside; it serves as a reserve where excess water accumulates away from the roots (read our article on drainage in a container without a hole). The main thing remains very measured watering. In an open desert terrarium, replace the humic potting mix with a very mineral cactus substrate.

🧰 The equipment needed to make a terrarium

A clear glass container, ideally about 30 cm wide and high according to the RHS, with a glass lid for the closed version. Then washed gravel, horticultural charcoal, potting mix, and moss: the University of Illinois estimates that these layers occupy about a quarter of the volume.

For tools: a long pair of tweezers or chopsticks and a spray bottle (RHS), a clean brush to clean the leaves (University of Illinois); for a narrow neck, a spoon attached to a stem (RHS).

The assembly takes one session; it is the balancing that requires patience. The Mississippi State University Extension considers the system balanced when almost no more condensation forms after these cycles.

🔀 The variants: closed, open, desert, in a bottle

columns: 4
columns_mobile: 2

🧭 Which terrarium according to your room and your light?

The right choice depends first on the light of the room, then on the space and the time you want to devote to it. A closed terrarium requires bright but indirect light; a desert terrarium, on the contrary, demands maximum light, which makes it a project for a very bright room. Here are our answers to the most frequent situations.

🫙 Closed, open, or desert terrarium: what difference for the plants?

The difference lies in the humidity of the air: a closed terrarium recycles its water and remains very humid, an open terrarium dries out faster. According to the University of Florida (UF IFAS) extension, the closed terrarium is better suited to tropical plants and the open terrarium is ideal for succulents and plants that like it dry.

The RHS (Royal Horticultural Society) confirms that succulents are particularly suited to open terrariums. So never put a cactus under glass: the saturated air causes their water-filled tissues to rot. Between the two, the humid open terrarium (wide-neck jar) accommodates Peperomia, Hypoestes, or Cryptanthus, with slightly more frequent watering.

Tillandsia are a special case: the RHS guide on air plants insists on a well-ventilated location and complete drying between two waterings, rot coming from stagnant water combined with confined air. They will therefore go in an open and ventilated container, never under glass.

📏 Adult size and growth rate: the forgotten criterion

The most important criterion is the adult size, because a plant sold in a few-centimeter pot can outgrow your jar in one season. The RHS asks to check the final height and spread on the label.

The NC State Extension warns, for example, that Soleirolia (Helxine) can live in a terrarium but eventually crowds out the other plants; in the ground, its forgotten fragments even grow back after pulling out.

Selaginella kraussiana also grows quickly, while Fittonia and Cryptanthus are classified as slow-growing. The Pilea peperomioides, fast-growing and 20 to 30 cm at maturity, is kept for a large open container.

Same logic for the coffee plant: sold as a small terrarium plant, it reaches about 1.2 to 1.8 m indoors according to the NC State Extension; it only stays under glass long enough to be young, then joins a real pot.

☀️ Terrarium plant without light: is it possible?

No: no plant lives without light, even in a terrarium. The RHS recommends bright indirect light for at least 6 hours a day, ideally near a north or east window, sheltered from the summer sun and heat sources.

The University of Missouri extension places shade-tolerant plants at a maximum of 10 feet from a clear window, or about 3 m. Beyond that, or in a room without a window, horticultural lighting becomes essential. Direct sunlight is the opposite excess: under glass, it overheats the air and burns the leaves.

🗓️ The terrarium through the seasons

A plant terrarium lives at the pace of light: it grows from spring to late summer and slows down in winter. Spring is the best time to arrange a jar or replace a plant that has become too large. In summer, the main risk is overheating if the sun reaches the glass.

In fall and winter, the light decreases: the RHS then allows a south or west window, without sticking the terrarium to a radiator, and the waterings are spaced out even more. The University of Missouri advises not to add fertilizer for at least 1 year after planting.

📅 Care calendar by season

⏳ How long does a terrarium last?

A plant terrarium has no fixed end date, but its composition remains decorative for one to two years at most: this is the usual display duration indicated by the State University of Mississippi. To prolong it, trim what touches the glass and replace the plant that has become too large.

The system itself can last much longer: the University of Missouri recalls that Dr. Nathaniel Ward, the originator of Ward's cases in the 19th century, saw a young fern and a grass grow for four years in a closed bottle, without adding water or opening the lid.

🐛 The most common mistakes with terrarium plants

Most failures come from a bad plant choice or an excess of water, much more than a lack of care. The RHS links yellowing leaves to overwatering and rot to excessive condensation. Here are the mistakes we see most often, and how to avoid them.

🌿 Our plant guides to arrange your terrarium

Each plant below has a complete care guide: light, watering, substrate, propagation, and toxicity. Start with slow and tolerant plants, then add the collector species.

You will find other humid air plants in our bathroom plant collection, all our Peperomia, our rare plants and all our indoor plants.

🔑 DIY terrarium kits: a good way to start?

Yes, a terrarium kit avoids the most common mistake: combining incompatible or too large plants for the container. Our kits gather the container, the layers (water reserve, activated charcoal, potting soil, moss), plants adapted to the format, and a building plan, with the tools according to the version.

It suits beginners and makes an original gift idea: the University of Illinois presents the terrarium as a family project and a unique gift for the holidays. Find all our terrarium kits to arrange, and the jars alone among our terrarium containers.

✅ The right choice in summary

To succeed with a terrarium, first choose the type of container according to your light, then plants with identical needs, low and slow-growing. Closed: Fittonia, small Peperomia, Pilea involucrata, Cryptanthus, jewel orchids, small ferns. Open desert-style: succulents and dwarf cacti, never under a bell jar.

Build simple layers, water very little, and rely on condensation thanks to our terrarium condensation guide.