Building a Christmas terrarium step by step
Around forty minutes for a first one, less once you know the order.
- Clean the glass. Inside and out, and let it dry fully. Fingerprints are impossible to reach once the plants are in.
- Drainage layer. Two to three cm of pebbles or lava rock at the bottom. This is where surplus water sits instead of around the roots.
- Substrate. Four to six cm of terrarium soil on top. Build it up higher at the back than the front, it makes the whole thing look deeper.
- Plants in, biggest first. Asparagus or fern at the back, Fittonia in the middle, moss and Selaginella at the front. Firm the soil around each root ball with a spoon or a stick.
- Water lightly. A small spray or a few spoons of water, no more. Wet soil is the single most common reason a terrarium fails.
- Decoration last. Set your figures once the planting is done, so you can see the composition you are working with.
- Lid on, then watch it. Some condensation on the glass is normal. Water running down the sides in sheets means too much water, so take the lid off for a day.
Which size to pick
Bigger jars are easier to keep alive, because a larger volume of air and soil is more stable. If you have never made one, do not start with the smallest.
- Around 19 to 20 cm, like Berry. Fits a windowsill or a desk. Two or three plants, one miniature.
- Around 23 cm, like Rudolph. The size most people end up happiest with. Room for planting in layers.
- Around 25 cm, like Jingle. Wide opening, easy to work in, holds a small village.
- Around 29 to 30 cm, like Holly. A centrepiece. Sits on a dining table or a sideboard and carries the room on its own.
All of our kits arrive as separate parts: glass, cork, drainage, substrate, plants and decoration. You assemble it yourself, which is the point. Browse the full range in the Christmas collection or the wider DIY terrarium kits.
A terrarium as a Christmas gift
It works as a gift for the same reason it works as a plant: nobody can kill it by forgetting about it. A few practical things worth knowing.
Build it or let them build it. A finished terrarium is the safer gift for someone who is not into plants. A kit is the better gift for someone who likes making things, and it doubles as something to do on a quiet afternoon between Christmas and New Year.
Personalise the lid. A cork lid with LED can be engraved with a name or a short line, and the light turns the terrarium into a lamp in the evening. This is the detail that moves it from plant to present.
Build it a week early, not on the day. Plants settle in and the moss perks up. A terrarium assembled two hours before you hand it over looks like a terrarium assembled two hours before you hand it over.
Looking after it through the winter
Winter indoors is hard on houseplants, mostly because of dry heated air. A closed terrarium sidesteps that entirely, since its humidity is sealed in. Three things still need attention.
Light
December daylight is weak and short. Move the jar closer to a window than you would in summer, but not onto a south-facing sill in direct sun. Glass plus direct sunlight cooks the plants.
Radiators
Do not stand it on or directly above one. The temperature swing pushes condensation hard and stresses the roots. A metre away is plenty.
Water
Less than you think, and less in winter than in summer. If the glass fogs lightly in the morning and clears through the day, the cycle is working. If it never fogs at all, add a spoon of water.
Ordering plants in winter
Live plants and freezing lorries do not mix. If overnight temperatures are near or below zero where you are, add a 72 hour heat pack to the box. It costs very little and it is the difference between plants arriving green and plants arriving translucent.
Also worth timing: December delivery windows fill up. Order in the last week of November or the first week of December if the terrarium has to be under a tree on a specific date.
Christmas terrariums around Europe
Handy to know if you are sending one abroad, because the date the gift needs to arrive is not the same everywhere.
- Germany and Austria open presents on Heiligabend, the evening of 24 December. Nikolaus on 6 December is a separate, smaller gift moment.
- The Netherlands and Belgium put most of the gift weight on Sinterklaas, 5 December, with Christmas itself spread over two days on 25 and 26 December.
- The UK and Ireland open on Christmas morning, with Boxing Day on 26 December.
If you are shipping to a German address for Heiligabend, work back from 23 December, not 25.
