If you’ve been around the plant community for a while, you’ve surely heard the phrase “bright, indirect light.” It’s mentioned in almost every resource across the web.
But what is bright, indirect sunlight, anyways, and how can you be sure your plants are getting that level of brightness?
Giving your plants the right amount of light is one of the most important factors for your plants. Still, plant care should not be overcomplicated because it can take away the fun.
Below we will explain how light works, how it affects your plants, and how to ensure that your plants receive the best light possible!
Table of Contents
What Do Indoor Plants Utilize Sunlight For?
Let’s get technical for a minute. Because understanding how plants use light can help you grasp the importance of bright, indirect light for houseplants!
Plants need light for energy production. This is a process called photosynthesis.
Apart from sunlight, plants also use carbon dioxide from the air and the water in the soil. The sunlight triggers a chemical reaction that converts carbon dioxide and water into glucose – the plant’s leading food and energy source!
The plant stores glucose (energy) in its cells. Inside these cells, you find chlorophyll. This pigment helps the plant absorb vast amounts of sunlight.
Did you know chlorophyll is the pigment that causes plants to appear green? This is because chlorophyll absorbs red and blue light from the sun and reflects green, making it appear green to our eyes!
Without sufficient sunlight, plants would not be able to create energy, and they would slowly wither away, so plants must have access to enough light to fuel their needs.
Why Does Sunlight Intensity Matter?
You may think that all light is equal, and as long as your plant is seeing some sun, it should be fine – but that’s not always the case. And to make that even more complicated, each plant has a different light requirement.
Some plants, like Calatheas, naturally grow underneath the canopy of large trees in a semi-shaded area. Others grow in open spaces and in the middle of the desert where there is full sun exposure, like eggplants and most cacti varieties!
Generally speaking, most plants cannot handle too much direct sunlight, and chlorophyll in their leaves may get destroyed by the heat and intensity of the sun.
The majority of houseplants will thrive when given bright, indirect sunlight. But how do you know if your plant is getting this type of light?
Light intensity is measured in footcandles (FC). Full exposure to summer sunlight generally has an intensity of 10,000 FC – regardless of latitude. Light intensity, or footcandles, decreases with distance from the light source.
It can be hard to determine what type of light your plants are getting, but luckily, there are ways to measure this using tools such as light meters, which measure light intensity with footcandles.
What Affects Light Intensity?
There is a seemingly endless of things that can affect natural light intensity. Everything from latitude and time of day plays a role, and if you want to give your plants the best chance to thrive, there are a few key things to know.
Time of Day
As the sun moves across the sky during the day, the intensity of the light changes. Sunlight will be the brightest when the sun is at the highest point in the sky, typically around noon.
Morning and late evening sun are much gentler, and most plants can handle this soft sun exposure.
The Current Season
It’s no secret that sunlight is more intense in summer than in winter. During the colder months, the sun hides behind clouds and shines for fewer hours daily. This can lead to changes in the light your plants receive!
Locations that used to get bright, indirect light during the summer may suddenly get much lower light exposure. As a result, plants tend to grow a lot slower in the winter or stop growing at all and enter a period of dormancy.
Curtains And Objects In Your Windows
Of course, using a window shade or placing objects on your windowsill will block the sunlight entering your room. What was once direct light can become indirect when the plant is behind a curtain.
This can help plants that can’t handle too much light living in a southern window or protect them from the sun during the warmest part of the day.
Potted Exotics Pro Tip: Consider using indoor hanging baskets if you have limited window options and need to shelter your plants from direct afternoon sunlight. Hanging baskets can make a great weekend DIY project too!
Southern vs. Northern Hemisphere
The way the light hits your windows depends on where you live. The sun travels straight across the equator, which means that people who live in tropical regions on the equator will see the sun travel across the sky in a straight line.
Those living in the southern hemisphere will see it angled slightly north and vice versa.
This means south-facing windows get more sun if you live in the northern hemisphere, which includes the United States.
Remember this when reading about northern and southern facing windows because it will significantly depend on where you are in the world.
The Different Light Levels For Plants
Whether you’re a new plant parent or a veteran gardener, light levels can be confusing. To give your plants the best shot to thrive, we suggest knowing about the following.
Direct sunlight occurs when the sun’s rays hit your plant directly, without any obstacles or objects between the plant and the sun.
Plants in south facing windows will receive the most direct sunlight. This type of sunlight is the most intense and bright light that plants can get and can be harsh, especially during the hottest parts of the day.
Where your lawn grass and lawn weeds can easily tolerate direct sunlight intensity, many delicate-leafed plants will burn when exposed to it!
Light indoors is much less intense than light outdoors because the sun gets filtered through the window. Outdoor sunlight has an intensity that can reach up to 10,000 footcandles during hot summer days, while indoor direct sunlight will be between 2,000 and 5,000.
Bright, Indirect Sunlight
Bright indirect light is filtered sunlight, meaning something either is between the sun and the plant or the light bounces off something before hitting your plant. This is the second brightest light exposure you can give a plant.
A west or east facing window will supply bright, indirect light exposure. Here, your houseplants will see some early morning or late afternoon sun and get indirect light for the rest of the day.
But, even if you only have north-facing windows, your plant can get a lot of light from this window during the warmer months.
In nature, bright, indirect sunlight is perfect for certain plants, including fungi like morel mushrooms, which only grow in this type of light and grow during a very limited time of year.
The majority of tropical plants are going to love this kind of light! It is not harsh enough to burn the leaves but bright enough to help this type of plant photosynthesize efficiently. Bright, indirect light will measure at about 1k footcandles.
Medium light falls right between bright, indirect light, and low light. Medium indirect light means there is still adequate light for plants to grow. Still, for many varieties, more sunlight is needed to thrive. Most plants with low light requirements will thrive in medium light!
Medium light will be between 500 and 1k FC when measured in footcandles.
Potted Exotics Pro Tip: A great way to creatively display medium-light plants is by using a moss pole to decorate a darker corner area of your room. Build a moss pole as a fun DIY project for you and the family, or run out and grab one from your local nursery.
Low light means the plant is far from the light source – or the sun, in this case. Think dark corners of the room a few feet away from the window sill and bathrooms with small windows. This is the least amount of light you can give a plant. Any less than low light would be no light at all!
While a few plants can tolerate little light, such as Snake Plants, Calathea, and ZZ Plants, they will not thrive in low light conditions. Many different plants will stop growing when they are in low-light conditions.
When this happens, it’s because they cannot produce enough energy to grow and sustain themselves.
Low light measures at 500 FC or below.
What Kind Of Light Do You Have?
Now that you know the different types of light, how can you figure out what kind of light your plants are getting? There are multiple ways to measure this.
You can measure the light your plants are getting by using only your hands, using the shadow technique. The kind of shadow you see determines the intensity of the light.
A sharp, defined shadow means direct light, a visible but less sharp shadow means indirect light, and little to no shadow means low light.
Of course, there are more precise ways of measuring light. However, it can be a valuable tool to ensure you give your plant the right conditions without purchasing a light intensity meter.
A light meter is a tool that measures foot candles. While this is a more detailed measurement, you must be clever when using it. Light intensity differs depending on the time of day and year. It’s best to measure in the afternoon when the sun is at its brightest around noon.
Plants That Thrive In Bright, Indirect Light
Any plant in the Philodendron genus will thrive when given bright, indirect light. The best spots for Philodendrons are in eastern or western windows, where they receive two to four hours of sunlight in the morning or late afternoon.
They do not tolerate hot afternoon sunlight, so protect them if you keep them in a southern window.
Being one of the most popular houseplants on the market, Monstera Deliciosa is an impressive plant that can grow up to 15 feet tall indoors. But getting your plant to this size means giving it optimal growing conditions!
Monstera Deliciosa loves bright indirect sunlight. The perfect spot for a Monstera would be a few feet from a south or west-facing window.
Looking for a bit of variation? Take a look at the different Monstera Adansonii varieties available to you!
The best place for this beautiful, bushy succulent is in bright but indirect light. You may think all succulents need direct sunlight to thrive, but that’s not true!
The majority of succulent plants will be able to grow very well in indirect light situations.
Jade Plants love getting hours of direct sunlight in the morning, so an east-facing window is ideal! If you plan to propagate new succulents, the right light conditions will be crucial.
Don’t be fooled by online plant care guides that advertise these tropical houseplants as low-light plants! In the wild, Calatheas grow underneath the canopy of giant trees, where they get partial shade.
Providing your Calathea with bright, indirect light in your home will promote healthy plant growth by allowing your plant to photosynthesize optimally.
How To Provide Bright, Indirect Light For Your Plants
Using Your Windows
The light your plants get will significantly depend on the direction your windows face. A south-facing window will catch much more sun than north facing windows.
South-facing windows can provide direct and indirect light, depending on what is in front. If you have a large tree in front of your south-facing window, the plant on your windowsill will get bright indirect sunlight.
If the sun hits your window directly, your plant will get direct sunlight, which may be too harsh on its foliage. You can use a sheer curtain to filter the light and protect your plant.
West or east-facing windows catch early morning sun or late evening sun, making them both excellent options. This light exposure is less intense than the sun during midday. East and west-facing windows provide indirect sunlight for the rest of the day.
Using Artificial Grow Lights
If you live in an apartment with small windows or don’t have room for your plants near the windows, the best way to provide bright, indirect light is by using supplemental lighting with artificial grow lights (LED lights or fluorescent bulbs).
There are wide varieties on the market available, but remember that fluorescent lights emit heat, which can increase the risk of burning your precious plants!
Opt for a full-spectrum, all-around grow light. Make sure not to place it too close to your plant’s leaves, or it will simulate the direct sun, and you risk burning them. Keep around 20 inches of space between the plant and the grow light for the best results.
During the cold, dark winter months, artificial lighting can be a great way to supplement natural light when insufficient. Leave your grow lights on for 6-8 hours daily, and always turn them off at night. Your plants will thank you!
Alternatively, vegetables like sugar snap peas need full sun conditions for optimal growth, so using grow lights for indoor pea plants is pretty much a non-negotiable.
FAQ About Light Intensity for Plants
How Far Away From A Window Is Bright Indirect Light?
The light intensity coming from your window will depend on the direction your window is facing. Different directions will provide different kinds of light. South-facing windows will give your plant bright, indirect light about 4-5 feet from the window.
A north-facing window will give your plant indirect light all day. The sun never directly hits the window, so you can place your plant directly in front of a northern window if you like. If you moved the plant a few feet back, it would receive medium light.
How Do I Know If My Room Has Bright Indirect Light?
The shadow test is an easy way to measure how much sunlight your plants are getting. Hold your hand up in front of a wall and check the shadow; if you see a shadow without a distinct, sharp edge, you have bright, indirect light.
You are dealing with direct light (bright sunlight) if your shadow has a sharp edge. No shadow or a very faint shadow means medium to low light.
Does Indirect Sunlight Give Vitamin D?
Yes. Indirect sunlight, which you can receive while sitting under the shade of an umbrella, can still provide us as humans with enough vitamin D to satisfy our daily needs. In the shade, our bodies absorb scattered UVB rays, which are just less concentrated with the vitamin than direct rays.
However, plants have little to no use for vitamin D, and it is rarely found in natural food sources.