A living landscape under glass, almost self-sufficient

A plant terrarium is a miniature garden that lives at its own pace. Closed, it recycles its own water: moisture evaporates, condenses on the glass and falls back onto the mosses and ferns. Open, it houses succulents and cacti that love dry air and light. The first choice to make is therefore the format, and it depends on the plants you love and the light in your room.

For a first closed terrarium, follow the tutorial How to create a closed terrarium: drainage, an airy substrate, compact plants and cultivated mosses. If a white fuzz appears in the first few weeks, don't worry: our guide to mould in closed terrariums explains what to do.

Prefer a dry, graphic look? The succulent terrarium tutorial covers the open setup in detail. To start with everything you need in one place, check out the A miniature forest under glass project.

Closed or open terrarium: the first decision

A closed terrarium works like a small water cycle: the plants transpire, the moisture condenses on the wall and then runs back down into the substrate. It suits woodland-floor plants that like humid air, such as fittonias, spikemosses, small ferns and mosses. An open terrarium, on the contrary, lets the air circulate: it is the only possible choice for succulents and cacti, which rot in a confined atmosphere. The comparison Closed or open terrarium sets out the merits of each formula.

The layers of a tropical terrarium

A tropical terrarium is built up in layers: a drainage layer of clay pebbles or gravel, a thin separator so the soil does not work its way into it, a little horticultural charcoal, then an airy, slightly moist substrate. The plants come next, followed by the moss and the decorative elements. The complete step-by-step is in How to create a closed terrarium.

Choosing the right plants

Success depends above all on the plants being compatible with their container. Favour small, slow-growing species that will not touch the glass within a few months. The guide Which plants for a terrarium? presents the best-suited species, and our moss guide helps tell cushion mosses from flat mosses. The mosses in our selection are cultivated, not collected in the wild.

Light, watering and upkeep

Place the terrarium near a window, in bright light but never in direct sun: under glass, the temperature can climb very fast. A closed terrarium is watered rarely. A light mist in the morning is a good sign; a wall running with water all day long signals an excess, to be corrected by opening the container for a few hours. Remove dead leaves and trim regularly with the right tools.

To take it further, the project A tropical terrarium in a demijohn offers a more ambitious format, and A miniature desert a dry, bright version.

Where to find the rest

Getting started: the beginner's guide goes over the four decisions to take before buying, 12 terrarium ideas gives compositions to copy, the equipment you need lists the essentials, how much a terrarium costs and doing it cheaply give the budgets, which container to choose compares the formats, and kit or separate purchases settles the assembly question.

Understanding: how a closed terrarium works explains the water cycle and photosynthesis under glass, closed or open terrarium compares the two regimes, terrarium, vivarium, paludarium untangles the three words, and self-sufficient terrarium says what self-sufficiency really means.

The plants: the overall selection is in which plants for a terrarium. Species by species: fittonia, ficus pumila, peperomia, spikemoss, soleirolia, ferns, hypoestes, pilea, calathea and maranta, cryptanthus and carnivorous plants.

The mosses: the species guide, how to lay them, how to grow them, cushion or flat, keeping them before the build and whether you can take them from the forest.

The soil: which substrate to choose, the order of the layers, clay pebbles or pumice and what charcoal really does.

When things go wrong: terrarium too humid, too dry, too hot or in the sun, smelling bad, condensation, mould, fungus gnats, yellow leaves, moss turning brown and plants dying.

Upkeep: caring for a closed terrarium, watering and trimming.

Other builds: bottle terrarium, tropical terrarium for beginners, succulent terrarium, bioactive terrarium and its upkeep, and springtails.

By use: a terrarium on your desk, making one with a child and giving a terrarium as a gift.

Shop by type: closed terrariums, open terrariums, tropical plants, succulents and mosses.