We all know plants require light to grow. But there is more to the light we see every day, either from the bulb or other light sources. Read on to learn more about the light spectrum, its different types, and how they interact with the plants to bring about growth.
What Is The Light Spectrum?
We can describe the light spectrum as the range of wavelengths a light source produces. However, the term “light” refers to the wavelengths of the electromagnetic spectrum visible to the human eyes. Imagine the electromagnetic spectrum as a whole and the visible light as a part of a whole.
The visible light comprises specialized particles called photons. A light source, for example, a bulb, will emit photons once you turn it on. Our eyes can detect or read and interpret these photons and ultimately inform the color of light we see. The visible light you and I see comprises electromagnetic radiation in a certain range of wavelengths, i.e., from 380-740 nm (nanometers).
Other parts of the electromagnetic spectrum include Ultraviolet (100-400 nm), far-red (700-850 nm), and infra-red (700 – 106 nm). These other three groups of wavelengths are referred to as radiation.
Next, let’s look at how the light spectrum affects plant development.
How Does The Spectrum Affect Plant Development?
Plants sense or interpret lights differently, unlike humans, who interpret wavelengths to arrive at different colors. Plants do not have eyes, so they rely on specialized cells in their leaves (chlorophyll) to detect and respond to light energy. As a result, they only detect wavelengths that include ultraviolet radiation (260-380nm) and the visible portion of the spectrum (380-740 nm). The visible part of the spectrum – also called the visible light spectrum – comprises photosynthetically active radiation (PAR) (400-700 nm) and far-red radiation (700-850 nm).
Plants absorb this photosynthetically active radiation, serving two major purposes for plants. First, plants depend on this energy to make sugars, which are used for the growth of flowers, leaves, stems, and roots. This process of harvesting light energy for sugar production is called photosynthesis. Plants use light within the PAR wavelength for photosynthesis, including the red, blue, and green wavelengths.
Second, lights also serve as an information source for plants. Plants interpret the various light spectra differently and take these interpretations as indications of their environment. These indications inform how plants survive and reproduce in any environment. This chain of reactions is called photomorphogenesis, which describes how plants change their growth in response to the light spectrum they sense. Plants use light in a wider range of wavelengths – between 260-780 nm – for photomorphogenesis.
The light spectrum is not the only factor controlling plant responses; other factors like light intensity, growth environment, photoperiod, and plant varieties and species influence how plants grow.
Moving forward, let’s look at each light spectrum’s specific effects on plants’ growth.
What Are The Different Effects Of Different Light Spectrums On Plants?
Plants sense or interpret lights differently, unlike humans, who interpret wavelengths to
H2: What Are The Different Effects Of Different Light Spectrums On Plants?
Plant chlorophyll contains photoreceptors, which trigger different growth characteristics when they sense the photons of light of a specific spectrum. Therefore, altering the light spectrum can cause significant changes in how plants grow. For example, different wavelengths within the light spectrum affect fruiting, flowering yield, growth rate, fresh weight, color, flavor, root development, and other plant changes.
There are four different wavebands in full-spectrum light, and they are described below:
The blue light waveband falls within the range of 400-500 nm. The photons of the blue light cause varying degrees of changes in plants, especially in growth and flowering. Blue light can boost overall quality in most ornamental and leafy green plants. Plants require only a minimal amount of blue light to develop normally. In combination with other wavebands, blue light helps produce secondary metabolites, root development, and plant compactness. Growers can increase the intensity of blue light to over 30 μmol·m-2·s-1 to alter the flowering rate in daylength-sensitive plants. It can also help regulate growth, facilitate stomatal opening, and increase chlorophyll accumulation.
The red light waveband falls within the 600-700 nm range. It is most effective at increasing the photosynthesis rate and plant biomass accumulation. The most visible signs of plants grown under only red light include extended length and thin leaves. This pattern of growth is undesirable to most growers. That is why blue light is often introduced to balance the red light, resulting in compact plants with thicker leaves and an overall regular growth pattern. This indicates that light wavebands influence each other, and combining the right wavebands can ensure better and more desirable plant development.
The third light spectrum on the list is the green light, which falls within the 500-600 nm range. Contrary to popular belief, the green waveband is essential to plant growth despite its lower chlorophyll absorption rate. According to studies, green light plays a crucial role in photosynthesis, especially in leaves on the lower parts of the plant. In addition, the presence of green light in your full-spectrum light can make the work environment more pleasing to the eyes. Combining the right amount of green, blue, and red lights can influence the canopy position of a leaf and light absorption. The white light resulting from this combination also makes it easier to monitor plants’ growth and changes.
Ultraviolet (UV) light
The Ultraviolet (UV) waveband is between 280-400nm. It does not contribute directly to plant growth. If present in large quantities, the UV light can damage the internal components of a plant. Plants mitigate tissue damage caused by UV light by secreting protective compounds. That is why some plants become more purple or darker in color. Interestingly, studies have suggested that UV light may help activate the plant’s defense mechanism. For example, it helps produce various proteins that make plants poisonous to pests and resistant to environmental stress and certain diseases. UV light also has a solid potential to increase leaf thickness and coloration.
These four different light spectrums are available naturally and artificially. Outdoor plants can easily access them through the light from the sun. However, indoor plants must be provided with full-spectrum artificial lighting to access these light spectrums.
Spider Farmer Offers Best-In-Class Full Spectrum LED Grow Lights
If we agree that light is crucial to plants’ survival, then indoor growing or gardening requires an artificial light source. Over the last few years, LED grow light technology has been the go-to source of artificial lighting for indoor growers. Full-spectrum LED grow lights are advanced models of LED grow lights designed to provide plants with all the light spectrums a plant requires for optimal growth.
Spider Farmer is one of the most renowned LED grow light manufacturers in the current market. The brand offers a wide range of state-of-the-art full spectrum LED grow lights, all of which guarantee higher yield, lower heat, and longer lifespan. Unlike single-spectrum LED grow lights, these advanced models are designed to ensure your plants get all the required light spectra from a single source. So, instead of buying multiple single spectrum LED grow lights, you get a single, multi-faceted full-spectrum LED grow light. This saves you more money and installation time, and effort.
You can check out the best Spider Farmers full spectrum LED Grow Lights here.
2 thoughts on “How Does The Light Spectrum Affect Plant Growth”
Thank you for an easy to understand description of the four spectrums of light on plants. Jesus bless you. LCRFuller
Great lesson on indoor lighting!