Domakihub How to Make a Terrarium: A Step-by-Step Guide
Build a self-contained miniature garden that thrives indoors with minimal care.
Reviewed by Domakihub garden pros · 2026-06-23 · 5 min read
A terrarium is a small, enclosed or open glass garden that creates its own micro-ecosystem, making it a striking and low-maintenance addition to any home, holiday rental, or hotel lobby in Greece. The video above walks you through the process visually, while this guide breaks it down into clear, actionable steps you can follow with materials available at any garden centre. Whether you are decorating a seaside villa or a city apartment, a well-made terrarium adds a touch of living greenery that guests genuinely notice.
Closed vs. Open Terrariums: Which Should You Make?
A closed terrarium uses a lidded glass container and creates a self-sustaining water cycle — humidity condenses on the glass, drips back to the soil, and the plants recycle their own moisture. This makes closed terrariums almost entirely self-watering and ideal for ferns, mosses, and tropical plants that thrive in high humidity.
An open terrarium has no lid and allows air to circulate freely, which suits drought-tolerant plants like succulents and cacti. For Greek summers with low indoor humidity and bright light, open terrariums with succulents are the more forgiving choice for beginners and rental properties where hands-on care is limited.
Choosing the Right Container
Almost any clear glass vessel works: a large jar, a geometric glass terrarium frame, a repurposed fish tank, or even a vintage glass bottle. The key requirement is transparency so plants receive enough indirect light. For display in a rental property or hotel, geometric terrariums with clean lines tend to look the most polished and photograph well for listings.
Size matters more than most beginners expect. A container under 15 cm in diameter will dry out quickly and restrict root growth. Aim for at least 20 cm wide and 25 cm deep for a planted terrarium that will stay healthy for months without constant intervention.
How to Build Your Terrarium
- 1
Prepare and clean the container
Wash the glass thoroughly with warm water and a small amount of white vinegar to remove any residue, bacteria, or soap film. Allow it to dry completely before adding any materials. A clean container prevents mould from forming in the moist lower layers, which is the single most common reason terrariums fail within the first few weeks.
- 2
Add a drainage layer
Pour a 3–5 cm layer of coarse gravel, pebbles, or horticultural grit into the bottom of the container. This layer holds any excess water below the root zone so roots never sit in standing water. For closed terrariums, place a thin layer of activated charcoal (available at aquarium shops or garden centres) on top of the gravel. Charcoal absorbs gases and keeps the internal environment fresh, preventing the sour smell that can develop in sealed glass.
- 3
Add the substrate layer
Spoon in 5–8 cm of potting mix suited to your chosen plants. For tropical plants in a closed terrarium, use a peat-free, moisture-retaining mix. For succulents and cacti in an open terrarium, blend standard potting compost with an equal part of coarse sand or perlite to create fast-draining soil. Smooth the surface with a spoon handle or a folded piece of card, making sure the layer is deep enough for roots to spread.
- 4
Plant and arrange
Use a chopstick, pencil, or long spoon to dig small holes and gently position each plant. Start with the largest plant first to anchor the layout, then fill in with smaller accent plants and ground-cover moss. Leave at least a centimetre between each plant to allow for growth. For an open succulent terrarium, try combining different heights and textures — a tall echeveria, a trailing sedum, and a compact haworthia create instant visual interest without overcrowding.
- 5
Finish, water, and position
Top-dress the soil with a thin layer of decorative sand, fine gravel, or moss to give the terrarium a finished, professional look and to reduce surface evaporation. Water a closed terrarium lightly once at setup, then monitor: if condensation covers more than half the glass each morning, leave the lid slightly open for a few hours to release excess moisture. An open succulent terrarium needs watering only every two to three weeks. Place the finished terrarium in bright, indirect light — a spot near a north- or east-facing window is ideal indoors in Greece, away from the intense midday sun that can cook plants through the glass.
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FAQ
- What plants work best in a terrarium for a Greek home?
- For closed, humid terrariums, ferns (especially Nephrolepis and Asplenium), mosses, and small Fittonia plants are reliable choices and widely available at Greek garden centres. For open terrariums suited to Greece's warm, dry climate, hardy succulents such as Echeveria, Haworthia, and Sedum are ideal — they tolerate the heat and low winter humidity without specialist care.
- How often does a terrarium need watering?
- A closed terrarium typically needs watering only every four to six weeks, or not at all if it is cycling correctly — look for light condensation on the glass each morning as a sign of a healthy water cycle. An open succulent terrarium needs water every two to three weeks in summer and even less in winter. Always water lightly and allow the soil to dry out between waterings to avoid root rot.
- Can a terrarium be left in a holiday rental without regular care?
- Yes, a well-built closed terrarium with moss and ferns can go several weeks without any intervention, making it a smart decorative choice for rental properties. A succulent open terrarium is equally low-maintenance. Avoid placing either type in direct hot sunlight through glass, and instruct guests or a caretaker to water the open type once during stays longer than two weeks.