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Color Spectrums and Growing Cannabis: Mixed Spectrums

Updated: Jul 1, 2021

When it comes to growing cannabis, there’s a lot you have to know. One of the biggest contributing factors to a successful cannabis yield is a proper lighting setup, as well as a good understanding of the relationship between growing cannabis and the light spectrum. Today, that’s exactly what we’re talking about.

Below, we’re covering the basics of the light color spectrum and how it can help a cannabis plant flourish. From the specific colors you’ll find to when you’ll want to utilize them, Luna Cultivation is giving you an inside look into the world of cannabis and color spectrums. Let’s get started.

What is the Light Color Spectrum?

First thing’s first: what even is the light color spectrum? To understand how the light color spectrum impacts your cannabis plants, it’s crucial to know what it is and how it works in general.

You can think of light as a wave: it peaks at some points and dips low at others. The main way scientists measure light is through its frequency and wavelengths, though only a few frequencies/wavelengths are visible to the human eye. The lights that we can see from the light color spectrum are considered a part of the (aptly named) “visible light spectrum.”

The visible light spectrum contains light wavelengths that are between 380 and 700 nanometers, with colors ranging from reds to purples, greens, blues, and yellows. As atmospheric changes occur—particularly raising or lowering temperatures or cloud coverage—the amount of light we are exposed to is going to change.

All of this also applies to plants. However, plants can see other colors on the light spectrum that the human eye cannot, and they also highly benefit from these light waves in ways we’re just beginning to fully understand. Specifically, the light spectrum and cannabis have a very interesting symbiotic relationship that’s more than worth exploring to help perfect your cultivation.

The Impact of Different Color Spectrums on Cannabis

Each color on the color spectrum is going to create a different reaction in your cannabis plants. If utilized correctly, different colored lighting can seriously help to enhance your yield. However, this all depends on when your cannabis is used to being exposed to each wavelength, and how much.

Let’s get right into the different colors on the color spectrum and how they can influence your cultivation.


Red light, or far-red light, is the type of light that humans feel the most. Of course, we can pick up red light with our eyes, but our eyes cannot detect infrared lighting. (But, our skin sure does— this type of lighting translates as high heat.) Plants, however, can pick up red lights of varying strengths, and it is easily one of the most beneficial colors on the light spectrum for your cannabis plants.

Red light helps plants activate photosynthesis, the process of turning light into energy. When this is signaled in a plant, your cannabis will want to start flowering or growing the precious potent flowers you seek most from cultivation. Plants that are grown under the right amount of red light tend to produce a much bigger flower yield than those that aren’t.

Timing is crucial with red lights. While it is possible to grow your plants under purely red lighting, your plants are going to benefit the most when this red light is accurately measured and distributed during the right times. Typically, most growers turn to red lights during the flowering stage of the cannabis plant, as this is when the plant will need the most support and nourishment to grow as you please.

Far-red lighting is wonderful for helping to signal to a plant that it’s almost nighttime, as well. If your plant was grown under natural sunlight, as the sun goes down or up, your plant’s red-light exposure will move to far-red light exposure. Replicating this kind of lighting is a perfect way to get your plants on a regulated schedule, helping your plants flower at appropriate times every day.


Green lighting, on the other hand, is a much more versatile lighting color for cannabis plants. Green light can be used during various stages of a cannabis plant’s life cycle, helping to promote healthy growth and composition every step of the way.

In general, cultivators and scientists alike are still discovering the full potential of green lighting and all the ways it can benefit your cannabis. Currently, studies have demonstrated that, in both the seedling and flowering stage of cannabis, green light utilization can help promote healthy root and stem growth, creating bigger, stronger cannabis plants overall.

Other studies have shown that small amounts of green light can also help boost a plant’s ability to absorb CO2 and water, though this is just beginning to be looked into.

Thankfully, green lighting is found in most other colored lights, like blue and red, so you don’t necessarily have to buy purely green lights to get the benefits. However, purely green lights are wonderful for checking on your plants as they sleep: this gentle form of light doesn’t disturb sleep and allows you to examine your plant effectively and non-invasively.


Blue and red lights are some of the most important colors on the color spectrum for cannabis plants. Blue lights help to signal cannabis growth: as plants detect blue light, they will start to grow towards it in a healthy, strong fashion. But, if there isn’t any blue light for plants to grow towards, they will start to think that they are shaded by other plants. Thus, your cannabis will begin to grow sporadically, completely ruining your crop.

During the vegetative stage of your cannabis plant—where all that your plant is doing is growing—being exposed to blue light is integral. This will help ensure that your cannabis plants grow to be not only strong and potent, but uniform and attractive, too. These qualities are crucial in producing a successful yield. Thanks, blue light.

Similar to far-red lighting, blue also helps to indicate to a plant that the day is coming to an end. Blue light typically indicates cooler temperatures and lack of sunlight, so using these can help to manipulate your plant’s sleep cycle into one that’s healthy and works for your schedule.


Finally, let’s talk about UVA and UVB lighting. Most people are familiar with UVA/UVB lighting because of its effect on the human skin. For us, we use things like sunscreen to protect our bodies from natural UV rays. Plants act similarly: as they’re exposed to UV rays, they create chemicals, enzymes, and compounds to help protect themselves from this form of lighting. While the science is still new, it appears as though this kind of reaction can help produce higher levels of THC and terpenes.

Of course, this must be a delicate balance. The harsh levels of UV can easily damage a plant if not careful. However, in small doses and during the right stage of the growth cycle, this lighting can spur the proper reaction. Growers who properly utilize UVA/UVB lighting have been known to test for higher levels of THC and terpenes, though other cannabinoids levels may also be affected. This kind of risk is entirely up to you!

The Best Colors For Every Stage of the Cannabis Plant

At the end of the day, if you’re hoping to achieve a successful cannabis yield, understanding how the color spectrum impacts the cannabis plant can make a world of difference. From increasing THC percentages to growing bigger, stronger plants and more potent flowers, colored lighting can do it all.

Luna Cultivation understands both the importance of proper cannabis lighting, as well as how confusing it can be at times. That’s why we’re here to make the process as straightforward and easy to understand as possible. For help with lighting, cultivation, and all things cannabis, Luna Cultivation can help.


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