One of the most misunderstood concepts in houseplant care is “bright indirect light.” The confusion surrounding bright, indirect light is a huge problem because the vast majority of the houseplants we keep need bright, indirect light.

Without more info, we often judge what seems like bright, indirect light by what we see with our eyes which perceive light very differently than plants do.

This blog post’s goal is to help you understand what qualifies as bright, indirect light and how to know when you’ve found it.

Table of Contents

Why do most houseplants require bright indirect light?

What is bright, indirect light?

Why does the amount of light your plant gets matter?

Can bright, indirect light be right on a windowsill?

Can bright, indirect light be 15 feet back from a window?

Does having huge windows or many windows in a room change how bright the light can be for your plants?

Do all of your houseplants need to be near a window?

Is there a way to place plants farther away from windows?

Is there a way to definitely measure or know how much light you are providing your plant with?

Conclusion

Why do most houseplants require bright indirect light?

Many of the plants we bring into our home are from the forest floor or are climbing among the trees. These plants are used to receiving lots of sunlight filtered through the tree canopy.

What is bright, indirect light?

Bright indirect light is diffuse or filtered light. It is light that is replicating the sun shining between the branches of trees on the plants below.

It does not mean that the sun never shines on your plant, despite the name implying it.

What bright, indirect light really means: WHEN sun shines on your plant, it only does so for a couple of hours or it shines most of the day through blinds or sheer curtains that reduce the intensity of the light a little.

Here is an analogy to compare the difference between bright indirect sunlight and direct sunlight:

Direct sunlight is dumping water on your head.

Bright, indirect light is slowly dumping water into a giant-sized colander being held over your head.

In both scenarios you get wet, but not in the same way or intensity. Dumping water on your head ensures that all of the water is dumped on you immediately.

Whereas dumping the water through a colander first lessens the amount being dumped on you by filtering it through something first. The colander might even splash some water over the sides preventing some of the water from ever reaching your head.

It is also somewhat similar to the difference between taking a bath (direct sun) and taking a shower (indirect or filtered sun).

Why does the amount of light your plant gets matter?

Leslie Halleck, a professional horticulturalist, describes the goal of indoor gardeners as ensuring a plant has everything it needs for photosynthesis.

Photosynthesis is the process by which plants use light to convert water and carbon dioxide into sugar (food) that can be used for growth and vigor.

Because light is what is powering the process that allows a plant to live and grow, sufficient light is vital to the health of your plant.

Can bright, indirect light be right on a windowsill?

Yes, especially if it is an Eastern or Western exposure. Both get a few hours of direct sun, with indirect sun for the rest of the day.

The afternoon direct sun is more intense than the morning sun, so plants with tender, burn-prone foliage often do better in windows with morning sun exposure.

Can bright, indirect light be 15 feet back from a window?

Most likely no. 15 feet from a window would probably be very low to no light. I have one plant that is about 6 feet from a medium-sized window and I know that I’m pushing my limits having it so far away.

For example: The middle of my living room, which has multiple large windows, appears brightly lit during the day, but not directly sunny. If you had asked me years ago whether this seemed like bright, indirect light, I would have told you, “Yes!”

In reality, the middle of my living room receives almost no useable light for plants. I was wrong. Very wrong.

I will rotate a couple of low light tolerant plants in and out of low light spaces in my home so one plant isn’t subjected to low light for long periods of time. All of my plants, barring the plant mentioned above, are right in or within 3 feet of a window.

Does having huge windows or many windows in a room change how much light is available for your plants?

Absolutely. Just like we perceive a room with huge windows to be brighter so does a plant. You may be able to (or even need to) place plants a little farther away to prevent burn if the windows are floor-to-ceiling. Or you could diffuse the light using blinds or a sheer curtain.

Do all of your houseplants need to be near a window?

Yes, that is exactly what it means 99% of the time.

I would only recommend that someone could keep a plant farther away from the window if they use grow lights or if they have floor to ceiling windows with an unobstructed view of the sky (no balconies, trees, porches, or other objects blocking sunlight from entering the window).

Darryl Cheng, from @HouseplantJournal on Instagram, recommends getting down to the level of your plant and seeing if that plant has a good view of the sky. The more daytime sky your plant can see, the more light it will receive.

Is there a way to place plants farther away from windows?

Yes! As mentioned above, you can use grow lights to successfully keep plants in any location of your home.

How to choose a grow light is a very complicated topic that will require its own post (or two), but I can HIGHLY recommend a book by Leslie Halleck called Gardening Under Lights – The Complete Guide for Indoor Growers (linked to Amazon through their affiliate program).

This books goes through all of the information you need to choose a grow light fit for your home and plants.

She covers everything from the science behind why light matters to all of the different ways to measure light and what the measurements are that you should know when trying to choose a grow light.

Is there a way to definitely measure or know how much light you are providing your plant with?

Yes!! There are both free and paid apps available for your phone and inexpensive equipment that you can use to measure the light in a given area.

The apps available on a smartphone are not as accurate as a light meter, but they can still provide an estimation of the light available relative to other places in your home. To find an app on your device, just search your app store for “light meter” and all of the options will come up!

If you are interested in having a more accurate reading of the light in your home, I cannot recommend a light meter highly enough.

The light meter I use is pictured and linked below from Amazon. It was eye-opening to see how much (or how little) light was available in some of the areas of my home.

I have a huge window in my bathroom that I thought would provide more than enough light for a low light tolerant plant on the counters in my bathroom. Once I had my light meter, I checked that area and realized that it barely hit 50 footcandles on the corner closest to the window. What a bummer!

When I use my light meter, I set the meter to measure light in footcandles and use the guide below to determine what kinds of plants I can put in each area.

Low Light: 75 to 200 footcandles
Medium Light: 200 – 500 footcandles
High Light: 500-1000 footcandles
Very High Light: at least 1000 footcandles

Light fluctuates throughout the day, from day to day, and from season to season. To get a more accurate idea of how much light is in a given area, it is best to take multiple measurements over a few days.

Conclusion

Bright, indirect light is a misleading term that makes it seem like no direct sunlight should ever hit your plant. This is not true at all.

Bright, indirect light is trying to describe the type of light plants receive when living in or beneath trees. The sun hits the plants, but is reduced in intensity because it is filtered through the branches of trees first.

When keeping plants indoors: bright, indirect light is available in East or West-facing windows, where the plants will receive a couple of hours of direct sun with the rest of the day being indirect sun. Bright, indirect light can also be manufactured by using blinds or sheer curtains on South-facing windows that receive direct sun all day so the light is filtered upon entrance.

I truly hope this post helps to demystify bright, indirect light. If there is anything that I missed or needs more clarification, let me know in the comments below or by emailing me at colleen(at)anaturalcuriosity.org

Happy growing!

Click to read last week’s article: Spotlighting Alocasia: Everything you want to know!

A Natural Curiosity
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