The ideal light for most terrarium plants is bright, indirect light. This means that the light does not come directly from the sun, but is filtered or reflected from a surface such as a window, curtain or wall. Bright indirect light is strong enough to provide the plants with enough energy to grow, but not so strong that it burns or dries them out.
Bright indirect light is especially good for tropical plants, which are often used in terrariums. These plants are used to growing under dense canopies where little direct sunlight reaches them. Some examples of plants that love bright indirect light are ferns, mosses, orchids, carnivorous plants, succulents or air plants.
In this article, we want to help you identify and create bright indirect light for your plants. We'll show you how to measure and optimize the light in your home, what tools and equipment you can use to enhance or supplement natural light, and how to care for and monitor your plants to maintain their health and beauty.
Table of Contents
A monstera plant in indirect light
To create bright indirect light for your plants, you first need to know how much light you have in the first place. To do this, you need to consider two aspects of light: intensity and duration.
The light intensity describes how strong the light is. The stronger the light is, the more energy it has. It depends on various factors, such as the distance to the light source, the angle of incidence of the light, or the nature of the surface that reflects or filters the light.
To measure the light intensity, you can use different tools and methods. One option is a luxmeter or light meter. These are devices that measure the brightness of light in lux or lumens per square meter. You can buy them online or at hardware stores. Another and especially cheaper option is the hand-shadow test. Here you hold your hand between the light source and the plant and observe the shadow on the plant. The sharper the shadow, the stronger the light.
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The light duration describes how long the light shines on your terrarium. The higher the light duration available, the more time the plants have to grow. However, it depends on an extremely wide range of factors such as the time of year, latitude, orientation of your windows or larger trees outside your window. In general, though, the days are longer in summer than in winter, and the closer you are to the equator, the more hours of sunlight you have. Light duration also affects the day-night rhythm of plants, which is important for their flowering and dormancy.
Light duration is much easier to determine than light intensity. Either check your smartphone's weather app to see when the sun rises and sets at your house, or simply observe when the light shines in throughout the day. There's no magic behind it.
Alternatively, you can quickly enter your location in this sunrise and sunset calculator: Sunrise and Sunset Calculator.
Guide values for light intensity and duration
Depending on the type of plants you have in your terrarium, they will need different amounts of light intensity and duration. Below you will find general information about the duration and intensity of different plant groups. Note, however, that this is of course only a very general indication and individual species may stand out.
- Ferns: 1000-1500 lux, 10-12 hours per day.
- Moss: 500-1000 lux, 8-10 hours per day.
- Orchids: 1500-3000 lux, 10-14 hours per day.
- Carnivorous plants: 3000-5000 lux, 12-16 hours per day.
- Succulents: 5000-10000 lux, 12-16 hours per day.
- Air plants: 3000-5000 lux, 10-14 hours per day.
If you click on the individual plant names, it will take you to the articles that look at whether these plants are suitable for a closed terrarium. Also very interesting!
How to create bright indirect light
Now that you know how much light your plants need, all you have to do is provide it. To do this, you need to consider several factors that affect the amount and quality of light that enters your space. You also need to know some ways to adjust the position and orientation of your plants to provide them with the best light. Finally, you need to know some tools and devices that can help you improve or supplement the natural light.
The role of windows and other factors
Windows are the most important sources of natural light in your home. They let sunlight in and distribute it throughout the room. But not all windows are the same. The amount and quality of light depends on several factors, such as:
- The cardinal direction: Windows with south orientation get the most direct sunlight during the day, while windows with north orientation get the least. Windows facing east get direct sunlight in the morning and windows facing west get direct sunlight in the evening, but comparatively little.
- The size and shape: The larger and wider the window is, the more light it lets in. The higher the window, the deeper the light penetrates into the room.
- The type of glass: The thicker or more tinted the glass, the less light it lets through. Some windows also have a UV protective layer or thermal insulation that can further reduce light. UV light carries the most energy, however, and plants need at least some of it.
- Shading: Curtains, blinds, shades or other window decorations can filter or block light. Trees, buildings, fences or other obstacles can also block or reflect light.
You should consider these factors when choosing a place for your terrarium. Ideally, you should choose a south, east or west facing window that is large enough to let in plenty of light, but not too much direct sunlight. You should also make sure that the window is not overly glazed or shaded, and that there are no obstructions blocking or distorting the light. If necessary, you can hang a thin curtain in front of the window to diffuse the light a bit.
Adjusting the position and orientation of plants
After you have found a suitable window for your terrarium, you still need to adjust the position and orientation of your plants to give them the best light. There are a few things to keep in mind:
- The distance to the window: The closer the plants are to the window, the more light they get. But be careful: if they are too close to the window, they can be exposed to direct sunlight, which can burn them or dry them out. So you should keep a distance of at least 30 cm between the window and the terrarium.
- The height in the room: The higher the plants are in the room, the more light they get. This is because the light decreases from the top to the bottom. So you should place your terrarium on a shelf, table or other elevated place.
- The orientation of the plants: Depending on how the plants are arranged in the terrarium, they get different amounts of light. So you should make sure that all plants get enough light and none are in the shade of others. You should also rotate the plants regularly so they grow evenly and don't stretch in one direction.
Here you can see three types and two photo examples of bright indirect light:
- Filtered light: Soft and uniform light passing through a semi-transparent surface such as a curtain or blind.
- Speckled Light: Spotty, irregular light that falls through a pitted surface such as a tree or pergola.
- Reflected light: Bright and concentrated light reflected from a shiny surface such as a wall or mirror.
The use of tools and equipment for bright indirect light
Sometimes natural light is not enough to provide your plants with bright indirect light. This can be the case, for example, in winter when the days are shorter and darker. Or if you are in a room without windows or with very little natural light. In such cases, you can use some tools and devices to enhance or supplement natural light. Here are some examples:
- Reflective surfaces: mirrors, foils or white walls that reflect and amplify the available light. You can place them near your terrarium to create more light.
- Artificial lights: Lamps, fixtures or candles that replace or supplement natural light. You can place them above or next to your terrarium to add more light. But be careful: not all artificial lights are suitable for plants. You should choose ones that have the right spectrum and intensity. For example, the CXhome LM301B.
- Humidifiers: These are devices that increase the humidity in the room. They can promote the growth and health of your plants by providing them with more water. They can also improve the light in the room by diffusing and softening it.
How to monitor and maintain bright indirect light
After you have created bright indirect light for your plants, you should make sure for a while that your plants react well to the new lighting. We have already discussed the various symptoms in the following article.
The signs and symptoms of too much or too little light
Your plants will tell you if they are happy with the light or not. You just have to watch for their signs and symptoms. Here are some examples:
- Too much light: Your plants may show leaf burn, discoloration, drying or wilting. They may also curl or drop their leaves to protect themselves from the light.
- Too little light: Your plants may show stunted growth, loss of color or pattern, loss of bloom or fragrance. They may also stretch or enlarge their leaves to catch more light. This process is called wilting and can cause your plants to become very unstable. In the worst case, they may even buckle.
You should take these signs and symptoms seriously and adjust lighting conditions accordingly to avoid or correct these problems.
The regular and seasonal inspection of the plants
You should regularly check your plants and watch for their signs and symptoms by regularly measuring and adjusting lighting conditions as necessary. This is especially important as the seasons change and natural light varies. For the best, even growth, plants also need to be rotated every once in a while to avoid leaning to one side.
Bright indirect light is the ideal light for most terrarium plants. It provides enough energy for them to grow, but not so much that it harms them. To create bright indirect light for your plants, you need to follow a few steps:
- Measure the light in your home and find out how much light your plants need.
- Choose a suitable place for your terrarium and adjust the position and orientation of your plants.
- Use some tools and devices to enhance or supplement natural light.
- Monitor and maintain your plants and lighting conditions regularly and seasonally.
Bright indirect light has many benefits for your plants. It promotes their growth, health and beauty. It gives them bright colors, lush leaves and fragrant flowers. It makes them happy and content.
But bright indirect light also has advantages for you. It makes your terrarium an eye-catcher in your home. It creates a pleasant atmosphere and a good room climate. It brings you joy and relaxation.
So, what are you waiting for? Try it out and create bright indirect light for your plants. Experiment and have fun with your plant arrangements and lighting setups. Share your feedback and questions in the comments or on social media. We look forward to hearing about your experiences!