Terrarium LED cork: how many hours to leave it on, and what it does for plants
An LED cork lights up a terrarium beautifully in the evening. What it really does for the plants, how many hours to leave it on, which batteries to use, and when you need a proper lamp.
In this guide
An LED cork is above all mood lighting: it shows off the moss and plants in the evening, but it does not replace daylight. Switch it on for a few hours in the evening, turn it off at night, and keep the terrarium in bright light without direct sun during the day. It runs on two AAA batteries. In a really dark room, you need a grow light as well.
What an LED cork does
The LED sits in the cork and lights the landscape from above. It has three effects:
- a decorative effect, the most visible: the jar becomes a small lantern;
- a light boost for moss, which makes do with little light;
- almost no heat, unlike a traditional bulb.
What it does not do: give leafy plants (fittonia, calathea, ficus) the amount of light they need to grow.
How many hours to leave it on
| Use | Duration | When |
|---|---|---|
| Decoration | 2 to 4 hours | In the evening |
| Boost for a moss terrarium | 4 to 6 hours | Late in the day |
| Never | All night | Plants need a dark period |
A timer is not essential: the habit of switching the jar on at dinner and off at bedtime is enough.
When you need a proper lamp
First move the terrarium closer to a window. If that is not possible, or if the room stays dark even at midday, a grow light placed above the jar takes over. Our guide lighting a terrarium explains how to choose and set it up.
Signs of a lack of light: stems stretching towards the glass, leaves turning pale, moss turning brown. See also terrarium plants for low light.
Batteries
Our LED corks take two AAA batteries, not included. Rechargeable batteries save you buying more. Open the compartment away from the jar, so you do not drop batteries or screws onto the moss, and wipe condensation off the cork before closing it.
Choosing your cork
The cork must match the neck. Measure the inside diameter before ordering. Our large LED cork (13.2 x 11.9 x 3.5 cm) is designed for our Sven XL, Milky, Bolder Bob, Fat Joe and Teddy bottles.
For a small format, the 5.5-litre Little Joe bottle comes with its LED cork.
Our guide terrarium corks explains how to measure a neck and choose the cork.
The ideal terrarium for an LED cork
An all-moss terrarium gets the most out of an LED cork: moss needs only a little light and looks great under soft lighting. That is the idea behind our Mousse & lumière kit.
In short
- The LED cork lights and showcases, it does not replace daylight.
- A few hours in the evening, never all night.
- Two AAA batteries, rechargeable if possible.
- In a dark room, add a grow light.
Sources
- Royal Horticultural Society (RHS), advice on light for houseplants.
- Technical sheets for our LED corks.
Frequently asked questions
How long should you leave a terrarium LED on?
For decoration, a few hours in the evening are enough. A cork LED is not bright enough to replace daylight: it should not stay on all night, as plants need a period of darkness.
Is an LED cork enough to grow plants?
No, except for moss in a fairly bright room. An LED cork is above all mood lighting. Terrarium plants need bright light without direct sun, or a proper grow light in a dark room.
Which batteries for a terrarium LED cork?
Our LED corks run on two AAA batteries, not included. Rechargeable batteries work well and cost less if you switch it on every evening.
Does the LED heat the terrarium?
Very little. An LED gives off much less heat than a traditional bulb. That is why it can be fitted in a cork, just above the plants, without harming them.
