What Is Bright Indirect Light For Plants? - Mr.Houseplant (2024)

There aren’t many things that confuse plant parents as much as the notion of bright indirect light. One of the reasons is that although it might be easy to define bright indirect light in general terms, when it comes to its practical use, many variables need to be taken into account.

The questions I usually get from indoor gardening lovers range from what exactly bright indirect light is to how it differs from direct light. Read on to find out what are the proper lighting conditions for your indoor garden. Learn everything about bright indirect light and its importance for your plants and indoor garden.

What Is Direct Light?

Direct light is when the sun is shining directly onto the leaves of a plant. If you’re in the position of a plant, the plant can see the sun from it’s location.

What Is Indirect Sunlight?

Indirect sunlight has the same meaning as indirect light, however indirect sunlight is a bit of a misleading term. The word “sunlight” can be the cause of confusion as the word “sunlight” alone refers to direct sun. It’s more clear to use the term indirect light instead of the term indirect sunlight.

There are two ways to measure bright indirect light. Bright indirect light can be measured with:

• a light meter or
• a light meter app.

How to Measure Light with a Light Meter

The best way to measure natural light is with a light meter. Light meters are inexpensive tools that cost between $20-30. They are very user-friendly. You just need to position them above a plant and point them towards the window/light source. The meter will show the amount of light your plant is getting at that particular moment.

For most plants the goal is to have bright indirect light (light over 3,000 lux), but the more indirect light you can provide the better. If you can provide 10,000-15,000 lux your plant will grow even faster and be much happier. The amount of light in your home will depend on the time of day. A light meter will show different light levels at different times of day.

I would always choose light meters over apps. Why? The reason is simple. These apps are imprecise because they aren’t calibrated for different mobile phone types. And to calibrate them, you need to use a light meter. This makes the apps entirely redundant (and futile).

However, there is always an exception to the rule. There is an app that I do recommend, and it is called Photone. What sets it apart from other apps is that it is already calibrated for different mobile phone types. In my experience, it shows the correct measures 9 out of 10 times.

Can I See a Bright Indirect Light Example?

What Is Medium Indirect Light?

Medium indirect light means indirect light (light where the sun isn’t shining directly on the plant’s leaves) between 750 lux (75 foot candles) and 3,000 lux (300 foot candles).

Full-sun means that your plant is exposed to direct sun for most of the day. It will depend a lot on your plant type, but this type of overexposure can damage or even kill your plant. As a general rule of thumb, keeping your plant in direct sun in the early morning or late afternoon is okay, for 1-2 hours.

Filtered light is pretty much a synonym for indirect light. Filtered light means that your plant is getting direct sun, but it is shielded from sun rays by a sheer curtain. The curtain acts like a buffer that softens the sun’s ray and prevents your plant from being sunburnt.

Yes, light through a window is considered direct sunlight. If the sun directly falls on your plant’s leaves (even through a window), that is direct sunlight. The intensity of direct sun through a window is lower compared to direct sun outdoors. But it is still considered direct sunlight. Note that too much exposure even through a window can cause sunburns.

If there is a white curtain on the window in front of your plant, it is no longer direct sunlight but indirect, filtered light.

There are two ways to tell if your indoor plant is getting enough light:

1. By measuring the intensity of light with a light meter and comparing it to the values in the table I am sharing with you at the end of this article and
2. by observing the growth of the plant

When it comes to measuring light for plants, the values I provided in the table are based on different resources such are agricultural extensions and books, adjusted based on my personal observations in the last 10 years of working with houseplants.

These aren’t strict requirements but rather recommendations. The values represent the minimal amount of light that low-light tolerant, medium-light tolerant, or bright light plants will be able to survive and thrive.

If we speak about observing the plant’s growth, a few indicators can tell if your plant is getting enough light. If your plant puts out new growth, leaves have their expected size, and are healthy, it usually means your plant is getting enough light. If internodes (spaces between leaved/nodes) are of the same size and are not increasing, this is usually a sign your plant is getting sufficient light. However, if the stems are long and spindly and internodes are get bigger, that isn’t a good sign. It implies that your plant isn’t getting enough light.

Sometimes, small leaves can indicate insufficient light, but I would like to point out that you shouldn’t base your opinion on this factor. There could be multiple reasons for leaves being small. So don’t immediately jump to the conclusion that it is the lack of light.

The placement/location of your houseplant considerably affects the level of light it will get. Light intensity drops significantly with distance. The further your plant is from the window, the less light it gets. In other words, light intensity decreases exponentially with distance. Putting your plant 3 feet away from a window, instead of near a window, will greatly reduce the amount of light your plant gets. What also plays a role is the unobstructed view of the sky. The larger the unobstructed view of the sky a plant has, the more light it’s getting.

And it isn’t only the placement of the plant that affects the light intensity. It is also the window position.

A south facing window will provide the most light for indoor plants if you live in the northern hemisphere. It will also provide the biggest amount of direct sunlight, especially in winter months when the sun is lower in the sky.

They are followed by the east facing windows. East facing windows get a somewhat lower amount of indirect light for plants, and a shorter amount of direct sunlight as well, early in the morning.

North Facing Window

The worst option for indoor plants are the north facing windows, as they get the least amount of indirect light, and no direct sun.

If you live in the Southern hemisphere, the situation is reversed. The north facing windows get the most light, followed by west facing windows, then east facing windows, whereas the south facing windows get the least amount of light.

To provide bright indirect light for your plants, place your plant on the window ledge or in front of the brightest window. If you can’t put it right in front of the window, put it as near as possible. The closer to the window, the better (each foot away from a window makes a big difference). If you do have more than one window to choose from, choose the southern one (in the northern hemisphere), or the northern one (in the southern hemisphere). The window where you put your plant should have a clear, unobstructed view of the sky, with no trees, buildings or awnings blocking the view.

If you can’t provide your plants bright indirect light, consider getting grow lights or getting plants that are low light tolerant. Of course, in an optimal situation, you’ll be living in a flat with large windows, a clear view of the sky, and windows facing just the right direction. Unfortunately, this is often not possible. But fortunately, the rescue comes in the form of artificial lights (grow lights). If you choose a good, tested artificial light, you can achieve the equivalent of bright indirect light. Even direct sunlight.

There are some important things you need to take into account when using a grow light:

• Choosing a good grow light, the one which produces sufficient intensity. Usually, people tend to buy very weak ones that only work at very close distances, 2-4 inches away.
• Setting it up properly: remember that the light intensity drops with distance. Keep this in mind when positioning your grow light.
• Adjusting the duration, that is, how long the light will be on. I keep my lights on from 8-16 hours per day. The duration depends on whether you are just supplementing natural light or replacing it.

If you want to know more about this topic, check out my post on the best and affordable LED grow lights for your houseplants.

To determine how much light your plant needs, check out the values in the table below.

The amount of light listed in the minimal amount column is the bare minimum that the plant needs in order to look ok.

The optimal amount is the minimum you should be aiming for. But the more light you can provide the better. Low light tolerant and medium indirect light plants will love receiving bright indirect light!

Commercial light levels are the levels used by nurseries in commercial production of houseplants. I added them as a demonstration of just how high light levels are being used in commercial production. Since we can’t provide even close to those amounts of light at home, we shouldn’t expect our plants to look as great or grow as fast as plants in nurseries.

Direct and Indirect Light Requirements By Plant

The main reason I decided to write this blog was to shed more light on lighting conditions (no pun intended), on the topic many plant parents, even gardening experts, find confusing. Another wish of mine was to show that you don’t need perfect natural light to grow healthy plants. You can come a long way with grow lights and regularly measuring the light intensity.

Light is one of the most crucial factors for plants. They thrive when they get sufficient light. The right amount boosts photosynthesis. As a result, plants grow faster, are happier and healthier and care of houseplants is easier. By providing your plant with sufficient light, you help it remain healthy, strong, and live longer.