The growth of a plant may seem like a simple and easy process.
Keeping a plant alive can be easy, but helping it thrive requires much more effort. You want your plant to grow well because it will produce higher yields when it is healthy.
Plants need water, certain essential nutrients—not too much and not too little—and they must be placed in an environment with light for a specific period of time.
However, not many people know how the amount of light can influence plant growth… until now.
In this article, we will explain how different light colors affect plant growth, take a closer look at the characteristics of light, and show how you can use different colored LED grow lights or full-spectrum white LED grow lights to change plant traits and help them grow faster and stronger.
What is visible light?
Full-spectrum light
An important component in plant growth, aside from water and oxygen, is light. By receiving light, plants can convert sunlight into nutrients they can use. This process is called photosynthesis. Water, oxygen, and sunlight form the holy trinity for plants.
The process of photosynthesis
Visible light is part of the electromagnetic spectrum. Visible light is only a very small section of that spectrum. The visible light we perceive behaves as a wave. Therefore, it exhibits different properties depending on its wavelength. For example, a light source with a wavelength of about 650 nm will be detected as red.
Cannabis plants are extremely sensitive to light. In addition to needing the right amount of light within the appropriate spectrum, the type of light and spectrum required also differs depending on the plant’s growth stage. For example, during the vegetative stage, blue light is most beneficial because it promotes vegetative growth.
Chlorophyll is the green pigment in plants responsible for carrying out photosynthesis. There are two different types of chlorophyll: chlorophyll A and chlorophyll B. Chlorophyll A is responsible for most of the photosynthesis and absorbs red and orange light. Chlorophyll B increases the amount of light spectrum the plant can use to generate energy and absorbs blue–violet light. UV light is also important for plants.
Many studies have been conducted on how different light colors can have different effects on plant growth.
Natural sunlight provides all visible light spectra. In summer, there are more blue–green wavelengths, helping plants grow large and strong. In late summer and autumn, when the sun sinks closer to the horizon in the evening, there are more orange–red wavelengths. These wavelengths help plants flower and reproduce before winter arrives.
How do light colors affect plant growth?
Light plays a crucial role in the different growth stages of plants. In fact, without light, most of the plant life we see around us wouldn’t even exist!
So, what is the science behind this?
Plants are organisms that create their own food through photosynthesis in their leaves, and one of the key factors for this process is the presence of light.
A green pigment called chlorophyll captures energy from light, and plants undergo several subsequent processes to use that light to create food for themselves.
When plants produce more food, they grow larger and produce more plant material. But do all types and colors of light create the same amount of energy? We will discuss this in the next few sections.
Which light color is best for plant growth?
Before finding the answer, we need to understand how light color affects plant growth. You’ll learn soon.
Although plants absorb a certain amount of energy from all light colors, the absorption rate varies greatly between colors—and plant growth varies accordingly. More absorption means more growth!
The reason for these differences lies in the varying wavelengths of different light colors. Depending on whether the wavelength is long or short, the plant will absorb the corresponding amount of energy.
These wavelengths vary across different color ranges in the spectrum. At one end of the spectrum are deep purple and blue shades; at the other end, we find shades of orange and red.
Let’s take a look at how plants absorb these different colors and how they affect plant growth.
Purple or Violet Light
Light with purple or violet hues has the shortest wavelengths among all light types, and therefore it also has the highest energy.
Plants easily absorb a large amount of this light during photosynthesis, and these shades play an important role in the plant’s growth during the vegetative stage.
Purple light promotes the growth and development of leaf structures, and it also helps produce fruits and vegetables with richer flavor and aroma.
Furthermore, plants produce more antioxidants when exposed to this type of light.
Overall, purple or violet light is a wonderful gift for our green friends if you’re wondering how light affects plant growth!
Blue Light
Blue light is also easily absorbed by plants due to its short wavelength and high energy potential.
These types of light are essential during the early stages of plant growth because they allow plants to produce more chlorophyll in their leaves, helping them absorb more light later on.
During germination, plants need to absorb a large amount of blue light to ensure strong stems and roots, as well as to help the leaves develop more quickly.
In fact, without sufficient blue light, seedlings may never emerge from the soil.
Green Light
Although plants absorb a limited amount of green light, they don’t actually prefer it. Since most parts of a plant are already green due to the presence of chlorophyll, green light is absorbed the least and is therefore one of the least effective light types for plant growth.
Green light is mostly reflected off the plant’s surface, making the plant appear greener than it actually is. In short, it is best not to shine green light on plants because it does not provide significant benefits at any stage.
Red Light
You’ll be surprised to learn how red light affects plant growth!
Red light has the longest wavelength in the color spectrum, and therefore it has the least amount of energy. Shades of red and orange play a crucial role in a plant’s development, and their presence is essential during the flowering and blooming stages.
Moreover, red light helps prevent the breakdown of chlorophyll, allowing plants to absorb more light and retain more energy for further growth.
Although these types of light are not necessary during the early growth stages, when red and blue light are combined, they produce a significant effect in creating larger and healthier leaves. So yes, red light is a big “yes” for plants—but… only if they could talk!
How Does Yellow Light Affect Plant Growth?
Yellow light plays virtually no role in plant development. In fact, scientists suggest that removing yellow light may actually help plants grow healthier compared to those exposed to it.
This type of light is considered the least beneficial for any plant, and there is still no clear evidence of a significant contribution of yellow light to plant growth.
Now that you understand which light colors have the most or least impact on plant growth, it’s important to know how light intensity affects the development and productivity of plants.
All plants have an optimal and peak light intensity at which they thrive and achieve their fastest growth rates.
Although different plant species have different peak intensities, exceeding the optimal light intensity can negatively affect plant growth.
Conclusion
Plants respond differently to different colors of light.
The Color Of Light Affect Plant Growth
Everyone knows that plants are food factories, and most are aware that their energy source is light. The process of converting light into food is called photosynthesis. However, what you may not know is that the color of light significantly affects the amount of energy a plant absorbs. This is because different light colors have different wavelengths, and these wavelengths—such as infrared light—provide different energy levels depending on whether they are long or short.
The highest-energy light is found at the violet or purple end of the visible spectrum. Violet and purple light have short wavelengths and thus high energy. At the other end of the spectrum is red light, which has long wavelengths and emits lower energy.
Regardless of whether the light is red or violet, plants will absorb a certain amount of energy from the light they receive. Green light is the least effective for plants because plants themselves are green due to chlorophyll.
Different colors of light also help plants achieve different goals. For example, blue light promotes vegetative leaf growth. Red light, when combined with blue light, allows plants to flower. Cool fluorescent light is very effective for indoor plant growth.
Understanding how different light colors affect plant activity is critical in a world dependent on crop-based food. Modern LED technology allows precise control over the colors of light provided to plants in controlled environments.
Now, we can design lighting systems to promote flowering or increase fruit yield. Many plant functions can be improved and optimized simply by understanding which light colors they respond to.
For a world facing hunger and the impacts of global warming, this is incredibly important. It enables us to provide environmentally friendly alternatives to improve plant quality and growth without relying on harsh fertilizers or genetically modified foods.
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