The growth of a plant might seem like a simple and straightforward process.
While keeping the plant alive can be easy, getting it to thrive can take a bit more work. You want your plant to thrive as it will yield more cannabis if it is healthy.
The plant needs water, the plant needs certain nutrients- not too much or too little, and it needs to be in an environment where it receives light for a certain amount of time.
However, not many know how much light can have an impact on the development of a plant… until now.
In this post, We will explain how different color lights affect plant growth, jumping into detail on the characteristics that light possesses, and how you can use different colored LED grow lights to change the properties of plants and make plants grow faster and stronger.
What Exactly Is Visible Light?
A crucial component in the growth of a plant besides water and oxygen, is light. By receiving it, a plant is able to convert sunlight into nutrients that it can use. This process is called photosynthesis. Water, oxygen, and sunlight make the holy trinity for plants.
Visible light is part of the electromagnetic spectrum. Visible light is a tiny portion of that spectrum. Visible light as we perceive it behaves as a wave. As such, it displays different properties depending on its wavelength. For example, a source of light with a wavelength of around 650 nm will be detected as having a red color.
Cannabis plants are very sensitive to light. Beyond needing the right amount of the right spectrum of light, the type of light and spectrum vary depending on the stage of growth your plant is in. For example, when your plant is in its vegetative stage of growth, blue light is the most beneficial as it promotes vegetative growth.
Chlorophyll is the green pigment in plants responsible for conducting photosynthesis. There are two different types of chlorophyll, chlorophyll A and chlorophyll B. Chlorophyll A is responsible for the majority of photosynthesis and absorbs red and orange light. Chlorophyll B is responsible for increasing the amount of light spectrums a plant can use for energy and absorbs blue- violet light.
Multiple studies have been conducted on how different colors of lights can have varying effects on the growth of a plant.
Natural sunlight provides all spectrums of visible light. In summer, there are more blue-green wavelengths, which help plants grow big. In the late summer and fall, when the sun is lower on the horizon in the evening, there are more orange-red wavelengths. These wavelengths help plants grow flowers and reproduce before its winter.
So.. How do your grow lights mimic sunlight?
Thanks to the recent developments in LED (light emitting diode) grow light technology, specific light wavelengths can now be isolated in order to control the different physical properties that a plant displays as it develops throughout its life cycle. These properties include but are not limited to, height, weight, color, and texture, as well as the chemical composure of the plant itself.
As a plant grows, you can use LED grow lights to manipulate these physical properties depending on the plant characteristics that you desire. Grobo uses high-quality LED lights that change color depending on the stage of growth your plant is in.. basically, our grow lights mimic the perfect spectrum of light for your plant its entire life!
The Effects of Each Color of Light
In the following paragraphs, we will explain what each light color does, and the effects that adding or removing them will have. But first, here is a quick summary, with extended information following:
Ultraviolet - No exposure produces better growth
Violet - Enhances the color, taste, and aroma of plants
Blue - Increases the growth rate of plants
Green - Enhances chlorophyll production and is used as a pigment for proper plant viewing
Yellow - Plants exhibit less growth compared to blue and red light
Red - When combined with blue light it yields more leaves and crops, depending on what is being grown
Far Red - Speeds up the Phytochrome conversion which reduces the time a plant takes to go into a night-time state. This allows the plant to produce a greater yield
The reason why items are the color that they are is because some objects will absorb the wavelengths, and others will be reflected. For example, a leaf is green because it absorbs all visible light wavelengths except for green- green is reflected.
Black and white are not considered colors because black absorbs all visible light wavelengths, while white reflects them all. This is why black objects get hot in the sun faster than white items.
Fun Fact: Rainbows occur when white light is dispersed through water vapor. This is why it’s common to see rainbows after it rains!
Ultraviolet (10nm to 380 nm)
Ultraviolet is not part of the visible light spectrum, we humans cannot see it. Some animals can however.
Being exposed to UV light for a long period of time has harmful effects on humans. When exposed to it, your skin reacts by developing a tan.
Likewise, exposure for a long time to this type of light will damage the plants that you are growing. A study conducted demonstrated that plants raised without exposure to UV light exhibited enhanced growth. If growing outdoors, it is impossible to protect your plants from all UV light.
Crazy enough, there are different types of UV light. UV-A is a type of UV light especially harmful to cannabis plants, and they have adapted to defend themselves against this wavelength in the form of enzymes, chemicals, and antioxidants. In high concentrations, the plant cannot defend itself and will experience damage.
UV-B is another type of ultraviolet light, and it is actually beneficial in small amounts. In larger quantities, it can cause damage. The image below is of leaves that were exposed to a small amount of UV-B, and on the far right: too much UV-B light.
Violet (380 nm to 450 nm)
Studies have shown that when a plant receives visible violet light, the color, taste, and aroma of the plant are enhanced. Additionally, the plant’s antioxidants are able to perform their functions more efficiently, which prevents the cells in the plant from being damaged. Generally speaking, violet light is much less important than red and blue light.
Blue (450 nm to 495 nm)
Blue light has one of the largest effects on the development of a plant. Multiple studies have shown that exposing a plant to this color influences the formation of chlorophyll, which enables the plant to intake more energy from the sun. It also controls a plant’s cellular respiration and lessens water loss through evaporation during hot and dry conditions.
Blue light also has an effect on photosynthesis, and more exposure to this light can increase a plant’s growth and maturity rates. This process is called photomorphogenesis.
Blue light is most abundant during the spring. This helps promote dormant plants to start growing again as the weather warms up in temperate regions.
Overall, blue light has an influence over multiple functions in a plant’s life, and is a crucial color to have in your own grow room or grow box in order to ensure the most optimal growth.
Green (495 nm to 570 nm)
Most of the plants that we see around us possess a green color. This is due to the fact that they absorb all of the colors in the light spectrum (blue, red, violet, etc) but reflect the green one. As such, only the green light is bounced back to our eyes.
Even with the relatively low amount absorbed compared to the other colors, a study found that green light enhances the production of chlorophyll which helps with photosynthesis while giving the plants a greener color.
Overall, adding the green color to your plants does not have much effect in their life process compared to other light wavelengths.
Green light does have one major benefit when it comes to cannabis plants… since they cannot “see” green light, it does not interrupt the necessary dark periods. Using green light allows you to work on (defoliate, topping) your plant when it is supposed to be receiving no light.
Yellow (570 nm to 590 nm)
Since yellow has a similar wavelength to green they both show similar properties in plants. A source from NASA indicates that yellow light does not contribute to photosynthesis since the wavelength of the light is often reflected by the plant and is not absorbed.
Additionally, just like with green light, a study showed that when a plant was exposed to yellow light compared to blue and red, the growth of the plant tested was reduced. Basically, yellow is not that effective of a wavelength for plants.
Red (620 nm to 720 nm)
Exposure to red light is another crucial factor that contributes to the optimal development of a plant.
Individually, red light won’t have a major effect on a plant, but when combined with blue light, it makes the plant yield better results when flowering.
A study that compared red light, blue light, and a mixture of both indicated that even though plants that grew under red light yielded more leaves than the ones grown under blue lights, the combination of both produced a number of leaves which surpassed the plants who grew strictly under red light. A similar case occurred during the growth of wheat where the crop yielded far better results when grown under a mixture of red and blue light, compared to strictly red light.
Far Red (720 nm to 1000 nm)
Reminder: far-red light is not part of the visible light spectrum, which means we cannot see it.
Even though little absorption occurs with this type of light, it plays an important role during plant germination and flowering. Red light and far-red light go hand-in-hand in regards to the effects that they have on plants.
A regular plant has a phytochrome system which regulates its growth, adjusting itself depending on the type of light that it is exposed to.
In this system, there are two predominant forms of this protein, its biologically inactive form (Pr), and its biologically active form (Pfr). When a plant perceives the red light, Pr transforms into Pfr, and if a plant receives the far-red light, it's Pfr goes back to Pr. Pfr is important because it triggers plant growth, but it slowly reverts back to Pr over time when the plant is located in the dark. At the end of the day, a plant’s flowering and vegetative growth is directly influenced by the Pr to Pfr ratio.
An example on how the Far Red light properties can be used to your advantage to have a higher yield is seen in cannabis growth. During the day this plant exhibits the most flowering, and during the night it ripens. Being a short-day plant, in normally requires 12 hours of exposure to light, and 12 hours of darkness. Yet thanks to far-red light, it’s phytochrome conversion is sped up, making it go into a night state quicker and requiring less time in the darkness. This way, flowering can occur under a longer daylight period, which in turn produces a greater yield.
What is a Burple Light?
Out of all the colors mentioned above, the most crucial ones in the development of your plant are red and blue. Because of this, grow light manufacturers make grow lights that appear purple. However, these lights are not providing much, if any, violet wavelengths. The grow light contains both red and blue light, as they are the most crucial wavelengths needed for successful plant growth.
Adding or removing the other light colours will vary the appearance and texture of the plant you are growing and will cause your plant to grow with the characteristics that you seek.
At Grobo, we’ve been developing this LED technology for a proprietary blend of the wavelengths best suited for plant growth. As a Grobo user, you will be able to mix the light settings to the environment which best matches your needs and interests. Additionally, through the use of the far-red light incorporated in the product your plants grown will produce a higher yield compared to being just grown under plain light.
Are you ready to start growing cannabis stress-free? Check out Grobo.io today!