what color of light is best for plant growth

What Color of Light is Best for Plant Growth

All plants need light to grow, but scientists have found out that different colors affect a plant’s growth differently.

And although sunlight seems white because it has all the colors from the light spectrum, white light isn’t the answer to the question – what color light do plants grow best in?

So today we’ll talk more about which types of colors are out there and how do different colors of light affect plant growth. In short, you will learn what color of light is best for plant growth.

Understanding Visible Light and Colors

As humans, we can only see a portion of the electromagnetic spectrum that contains wavelengths of diverse frequencies from Gamma rays to radio waves.

Our eye can only distinguish wavelengths about 380 to 750 nm and this makes up the light spectrum. So every color you’ve ever seen is hidden somewhere in this spectrum.

It’s a widely known fact that by combining natural colors which include white, black, red, blue, and yellow, you get all other colors of the visible light spectrum. 

Now, because the sunlight contains all of these colors, it appears to be bright white, and with the absorption of light, the plants create necessary nutrients that, besides water and oxygen, feed the plant.

Knowing this, you would think that white light is the answer to the best plant growth.

But it’s been known that exposing your plants to different colors of light has different effects, and because indoor plant growing is becoming ever so popular, you can actually set up your own DIY grow light and use a specific color of light that affects your plant differently.

Let’s see what those colors of light are and under what color light do plants grow best.

How Each Color of Light Affects Plant Growth

As we already mentioned, all the colors you can see are somewhere in the 380 to 750 nm wavelength range. However, there are specific colors of light that actually help your plants in diverse ways.

Some affect plants more, some less, and the effects can vary from plant growth, development, to even creating protective properties.

So let’s see how do different colors of light affect plant growth and what is the best grow light (type) color.

Ultra-Violet (UV) Light

UV light is in the 10 to 380 nm range and is considered to be harmful to both humans and plants. And although ironically sunlight contains UV rays, because it’s filtered by the Earth’s atmosphere, the radiation it produces is minuscule compared to man-made UV light sources such as tanning booths.

One of the positive effects UV light brings to plants is that for some plants it can produce a protective resin that plants use to have protection from harmful rays.

This doesn’t mean you should put your plants under UV lights unless you’re planning to grow cannabis as this plant has great benefits from resin production and UV light is considered to be the best light spectrum for clones.

Typical house plants will get damaged and will start to wilt in most cases.

Violet Light

It’s known that violet-colored light can enhance the aroma and taste of certain plants, and can even affect color because it reacts with the plant’s green pigment also known as chlorophyll.

What violet light also does is interacts with the antioxidants in the plants making them richer with nutrients and healthier for consumption.

Although violet light doesn’t affect the plant’s growth as much as some other colors, in combination with colors such as red and blue, it can also have positive effects on growth.

Blue Light

If you’re asking yourself what color of light do plants grow best in, then the simplest answer is the color blue.

Blue light has an amazing effect on plants because chlorophyll absorbs it the easiest which makes the plant convert it to energy through the process of photosynthesis.

Blue Light

This means that the growth of the plant is taking place much faster and increases the maturity rate.

The way blue light does this is that it enhances the formation of chlorophyll with which more energy from the light source is being absorbed and produced.

Blue light also enhances the plant’s oxygen transmission or cellular respiration as it’s often called. Because the plant is getting more energy from the blue color light source, it means that it needs less water so blue light also cuts off water loss.

So if you want the best color light for your home grow lights, blue is definitely the best choice.

Green Light

Green is the color plants reflect but they absorb every single color of the light spectrum. This is because only the green color (produced by chlorophyll) is picked up by our retina and displays the plant’s green.

Now, terms of how much green light is good for plants are debatable.

Some people think that because the green color is already produced by chlorophyll, that the green light won’t do too much. But biologists have found out that green light helps plants produce chlorophyll and thus through photosynthesis makes them vividly greener.

Overall, it’s true that the color green doesn’t have any effects on the growth of the plant so it’s not the best choice for your indoor grow lights.

Yellow Light

Because yellow color lights are quite easy to get a hold of, some people actually prefer to use regular yellow light for their plants.  But how well would a plant grow under pure yellow light?

Well, because yellow light is quite near the green in the light spectrum, this color light will have similar effects on the plant.

However, yellow light won’t be absorbed by chlorophyll, rather it will be bounced back, and even though it can increase some growth compared to no light at all, but the effects are so minuscule that there’s no point in it actually using it as a grow light.

Red Light

It’s been widely known that red color light has a great impact on the plant’s foliage and makes the leaves more vivid and luscious.

Red light is also considered to be quite helpful for the blooming process, but standing on its own, it doesn’t have much effect on the actual growth of the plant.

That’s why red light is often combined with blue light because both colors are beneficial to plant growth.

And no, combining blue and red light won’t get you violet light, even though it might appear that way, so using violet light isn’t a red + blue light substitute.

Far Red Light

Far-red is actually invisible to our eyes because it sits so far at the light spectrum which makes it practically invisible.

Not only that, but because it has a high nanometre wavelength range, plants won’t absorb it as much as they would other light colors.

However, there are still some benefits to using far-red light. For example, if you combine it with red light, you get the enhanced effects of the red light such as better flowering at day, and ripening at night.

It also has great effects on cannabis and stimulates better yielding.

Still, you don’t want to use this light color on its own, but rather combine it with blue or red.

White Light

Contrary to popular belief, white light which is mostly found on LED lights isn’t white at all. It’s actually a combination of red, green, and blue colors which when mixed together seem white.

Of course, there are different types of white light and they include:

  • Cool white light – this light has a temperature of 6500K and has more blue than red and green.
  • Yellow white light – this light has a temperature of 3000K and has more red color light.
  • Normal white light – this light has a temperature around 4000K and has a perfect balance between the red, green, and blue color lights.

White light is actually the perfect light for your plants as it has all the necessary light colors we’ve already talked about that enhance the growth and blooming of your plant.

What Color of Light is Best for Plant Growth - white light

What’s great is that you can find white LED lights practically anywhere, and you can even use streaming lights, LED lamps, and so on.

Of course, using separate red, green, and blue color lights might slightly enhance the growth effect of your plant, but because you get all of them in the white light, it all comes down to personal preference.

“Burple” Light

Because out of all these light colors we’ve mentioned, red and blue have the most benefits for plant growth so that’s why many manufacturers of grow lights make “burple” lights, which don’t have anything to do with purple lights even though they are the exact same color.

“Burple” color lights only contain red and blue color lights and don’t even have the same wavelength as violet lights. This means that “burple” light will be mostly absorbed by the plant and it’ll stimulate both growth and maturity.

Overall, these lights are good for plants such as cabbage, or other leafy greens which have lots of leaves because the combination of blue and red will work like magic for foliage growth.

How to Choose the Right Type of Light?

Now that you are familiar with what color lights do plants grow best in, let’s talk about how to choose the right type of light for your plants.

There are 4 different light types that you can use for your plants if you want to grow them indoors.

Each type has a different application, but some light types can be used for most plant species.

Let’s see what these types are.

High-Intensity Discharge Lights

HID lights have an amazing light output and they’re regarded as lights with the best brightness. They are also used to cover larger areas of crops and are mainly used in grow tents.

Now, HID lights use special gas-filled bulbs that primarily come in white or yellow color, and as we’ve already said, white-color lights are perfect for growing most plant types as they contain red, green, and blue.

However, you can also find HID lights in different colors such as violet, blue, red, and so on.

So you want to use HID lights if you have a larger indoor plantation, or a grow tent, or a grow room where you need lots of lighting coverage, then they’re your safest bet.

Fluorescent Lights

Fluorescent lights are also a great choice for most gardeners as they last a very long time and they also produce a lot of blue light, which is beneficial for plant growth.

Apart from blue, they also produce other colors of the color spectrum, but not all, so they’re best for leafy plants which have a lot of foliage.

Some gardeners prefer fluorescent lights because they last long, don’t emit much heat and they also save a lot of energy, not to mention that they can cover a lot of space.

LED Lights

Most LED lights can produce white, red, or blue color and they’re quite popular among gardeners because they’re cheap, easy to find and provide the plants all the necessary light colors.

This means that they’re suitable for most plants, and what’s great is that you can determine how much light you need and simply add or remove the LED light bulbs as you wish.

You can use any LED lights you can find, and even make your own DIY LED lights at home for just a few bucks.

Incandescent Lights

As a gardener, you want to stay away from incandescent lights as they’re mostly used for looks rather than function. There’s a reason no one uses them anymore even for house lighting.

This is because incandescent lights mainly use yellow, or warm white light which doesn’t really provide your plants the best lighting and they’re also quite dimmer than other light types.

Some gardeners use them because they’re quite inexpensive, but in the end, they won’t make your plants grow any faster or better.

Frequently Asked Questions

How Does Blue Light Affect Plant Growth?

Blue light has the best absorption by the plant due to the green pigment every plant has, also known as chlorophyll. This chlorophyll absorbs the blue light and transfers it into energy through photosynthesis making the plant grow faster because it’s able to get more nutrients.

Why Are Grow Lights Purple?

Not all grow lights are purple, but for some plants such as cannabis, they are just perfect because they stimulate the production of protective resin which makes the plant more resistant to radiation. Purple light isn’t suitable for every plant type so it’s better to use a different color light after all.

What Type Of Light Is Best For Growing Plants Indoors?

Because plant growth under different colors of light is not only a matter of the plant species but also the environment the plant is in, the best type of light is blue light as it is best absorbed by the plant’s chlorophyll.

Why Do Plants Absorb Red and Blue Light?

Because chlorophyll reacts to different color lights and absorbs green the least, red and blue are so dissimilar to green that they are absorbed the best. One reason being also is because they are natural colors found in the plant’s surroundings.

Which Light is Better Yellow or White?

Yellow color has similar wavelengths as green and won’t be absorbed by the plant as much. While white color is comprised of red, green, and blue and has better absorption and thus is a better light color to have for your grow light.


So now you know everything about what color light do plants grow best in, you can easily pick the right color light for your indoor garden.

We hope that this article was helpful for you to expand your knowledge about plant care and hope that you choose the right light for your little green friends.

Good luck and happy gardening!