Mini terrarium in a small jar: which plants, which layers
A jam jar or a jar under one litre can become a terrarium. The plants that cope with so little space, the layers to scale down, and watering by the spoonful.
In this guide
A mini terrarium fits in a jar of 300 ml to 1 litre, as long as you scale down each layer and choose plants that do not grow big. Moss is the safest base. Allow a finger of drainage, a pinch of charcoal, two fingers of potting soil, then the moss. Water with a spoon and close it. The rest of this guide covers quantities and plants.
Which jar to choose
| Volume | What fits | Example |
|---|---|---|
| 200 to 500 ml | Moss alone, a small decoration | Jam jar, small spice jar |
| 0.5 to 1 litre | Moss + a mini fittonia or a small peperomia | Preserving jar, glass with lid |
| 1 to 3 litres | Two or three small plants, some relief | Large jar, small carboy |
A lid is better: in such a small volume, water evaporates quickly. The glass should be clear, without patterns, to let light through. Our guide which terrarium size to choose compares larger formats.
Plants that fit in a mini jar
- Cushion moss (Leucobryum): low and slow, it fills a jam jar on its own.
- Flat moss: it carpets the ground and shows off a pebble or a figurine.
- Mini fittonia: a touch of colour, in a jar of at least one litre.
- Small peperomia: round leaves, slow growth.
Avoid pilea, ficus, ferns and any plant that climbs. Within a few weeks, it would touch the lid. Our guide cushion moss or flat moss helps you choose the moss.
The layers, scaled down
In a half-litre jar:
- Drainage: 1 cm of clay balls or gravel.
- Activated charcoal: one teaspoon, in a thin layer.
- Potting soil: 2 to 3 cm, slightly moist, pressed down with your fingertips.
- Moss: laid flat, pressed so it touches the soil well.
- Decoration: a pebble, a piece of wood, a figurine. No more.
The purpose of each layer is explained in the layers of a terrarium. The S and M refill pack contains two moss cushions, 0.75 L of potting soil, 0.75 L of clay balls and 35 g of charcoal. It is designed for a container 10 to 20 cm in diameter: for a jam jar, part of it is enough, and the rest goes into the next jar.
Tools for a narrow neck
Fingers do not fit into a narrow jar. Long tweezers let you place the moss and decoration and remove a dead leaf. A dry brush cleans the glass after planting.
Watering by the spoonful
This is the most important rule. In such a small volume, a glass of water drowns everything.
- When planting: one to two tablespoons for a 500 ml jar, poured over the moss.
- Afterwards: nothing as long as there is condensation in the morning.
- If the moss turns pale and the glass stays dry for several days: one spoonful of water, no more.
If water stagnates at the bottom, open the jar for a few hours, see should you open a closed terrarium.
Where to put it
In bright light without direct sun: near a north- or east-facing window, or one or two metres from a sunnier window. Direct sun heats a small jar within minutes. On a dark desk, an LED cork makes up for it.
The kit to get started
If you prefer a ready-calibrated format, the Mousse & lumière kit follows the same principle in a 4.5-litre bottle, with the moss, the layers and an LED cork.
In short
- A jar of 300 ml to 1 litre, preferably with a lid.
- Moss above all, a single small plant above one litre.
- Every layer scaled down: 1 cm of drainage, 2 to 3 cm of potting soil.
- Water by the spoonful, bright light without direct sun.
Sources
- Royal Horticultural Society (RHS), advice on terrariums and choosing plants.
Frequently asked questions
Which plant for a mini terrarium?
Moss above all: it stays low and copes with a very small volume. You can add a mini fittonia or a small peperomia in a jar of at least one litre. Avoid fast-growing plants such as pilea or ficus.
Can a mini terrarium live in a jam jar?
Yes, with a lid and moss. A 300 to 500 ml jar is enough for a moss and a few bits of decoration. As the volume is small, you water with a spoon or a mister, never with a glass.
How long does a mini terrarium last?
Several months to several years for a well-lit moss mini terrarium. The smaller the jar, the more delicate the balance: one spoonful of water too many shows straight away.
