How Does The Spectrum of LED Cannabis Light Affect The Growing Industrial Cannabis Plants?

How does the spectrum of led Cannabis light affect the growing industrial Cannabis plants

Legal cannabis cultivation is basically indoor cultivation. In an indoor closed environment where sunlight is scarce, LED cannabis light lighting is an indispensable growing condition for cannabis. There are many types of grow lights on the market with different functions. To find suitable cannabis grow lights, we must have a deep understanding of the effects of LED grow lights on cannabis growth. Hence, we have to study the effect of different spectra on cannabis growth.

What is spectrum?

Natural light consists of a variety of different colors of light. The superposition of various light causes the natural light we see to appear white. The wavelengths of different colors of light are different and the refraction angles entering the medium are also different. According to this characteristic of light, the rays of natural light pass through the prism. We can see that white light is divided into a continuous spectrum of different colors, which is the visible light component of white light.

After years of research, plant growth is closely related to the changes in the external environment. Sunlight is one of the most important factors. Sunlight not only brings energy and signals to plant growth, but also regulates the growth state of plants. It is difficult for people to control natural light conditions. Therefore, growers cannot control the growth state of outdoor plants. With the development of agricultural technology, many crops now grow in indoor environments. Growers can adjust nutrients, carbon dioxide concentration and spectrum, so that crops can grow in the direction desired by growers.

What is the “best” spectrum for growing cannabis?


This is a very interesting question. Different spectra have different effects on the growth of cannabis. Each spectrum has its own unique effect. The requirements for spectrum at different stages of cannabis growth are also different. There is no optimal spectrum for cannabis growth. But at different stages of cannabis growth, growers can choose the best spectrum for cannabis growth according to their needs and the growing environment of cannabis.

Why can cannabis plants respond to the spectrum?

When cannabis plants are grown outdoors in the sun, the received spectrum actually provides cannabis plants with a lot of information about what is happening in the world around it. In spring and summer, more blue spectrum reaches the surface of the plant.

With the arrival of summer, the sunlight becomes more intense, and the spectrum of sunlight changes. Cannabis and other related plants are affected by the signal of spectral change, and their own growth status has also changed. The leaves will grow more rapidly. Plants grow to absorb more sunlight and grow better in the bright summer sunshine. According to the research, the signal of sunlight change from spring to summer is that blue light in sunlight spreads to plants.

Blue light-Blue light can promote the growth of cannabis leaves, inhibit the growth of cannabis stems, and allow cannabis to use as many nutrients as possible for leaf growth. The proportion of blue light can be adjusted at the growth stage of cannabis. Cannabis plants grown under such conditions are short but with large, healthy leaves.

When autumn comes, the sun changes from direct to oblique. The sun is refracted through the atmosphere, and more red light passes through the atmosphere and reaches the earth. Plants receive the signal of intensified red light when summer is over and autumn is coming, and are ready to bear fruit to prepare for the arrival of winter. When exposed to red light, cannabis accelerates the growth of stems. After the growth, the distance between cannabis leaves can better receive light and accumulate more nutrients for the fruit. In addition, the growth height is also conducive to the flowers of plants to contact the pollen in the flowing air and complete the pollination.

Yellow/red light-Red light is conducive to the growth of plant stems. During flowering, cannabis increases the proportion of red light in LED cannabis light, which is conducive to the growth, height and germination of cannabis. Plants growing under red light will enter the flowering cycle more quickly than plants growing under blue light.

Spectrum not only brings energy to plant growth, but also provides signals for plant growth. In order to better adapt to the environment and grow better, cannabis will change its growth state according to different spectra. Growers can use this characteristic of plants to regulate their growth. For example, if you want cannabis to blossom and sprout early, turn up the proportion of red light in the cannabis plant light; if you want the leaves of cannabis plants to be low and long, you can increase the proportion of blue light in the cannabis LED light. Make good use of different colors of light to send different signals for plant growth, so as to make plant growth move in a favorable direction.

How much does the spectrum affect plant growth?

The light intensity required for cannabis growth is relatively high. Light generally incorporates at least red light and blue light. Cannabis can grow normally under these light conditions. It is not difficult to get cannabis LED lights. There are plenty of LED grow lights that meet these conditions. Some reputable businesses (such as MOKOLight) can sell the right cannabis LED lights. Although plants can grow healthily without changing the spectrum, we should make good use of tools to properly adjust the spectrum of plants in different growth periods, which is more conducive to plant growth.

Different plants may respond differently to the spectrum. Some plants are almost unaffected after spectral adjustment, while some may have great changes in their growth state. Light is not the only factor affecting plant growth. Changes in other conditions can also affect plant growth. For example, increasing the proportion of red light in the spectrum will accelerate plant growth. Sometimes, reasonable nutrients and carbon dioxide concentration can also accelerate plant growth.

If the light intensity hitting the plant is too weak, even with a lot of blue light, the plant will not grow leaves, but will grow as tall as possible, because when the light is insufficient, the plant will grow as high as possible to obtain more sunlight; If the plant receives yellow light with high light intensity, the height of the plant is limited and plenty of leaves will grow, because at this time the plant obtains enough light and does not need to grow taller to obtain more.

Most grow lights on the market are full spectrum grow lights or red and blue spectrum grow lights. The light they emit basically contains the spectrum required for cannabis growth. Therefore, when selecting cannabis grow lights, the light intensity of the lamp is often much greater than that of the spectrum.

The best way to increase the yield is to increase the light intensity

In other words, giving plants more light than simply changing the spectrum can give you a greater yield return. Therefore, if it is possible for your plants to get more light (the highest), even if you add light in the “wrong” spectrum, this will increase your yield. Even adding the green spectrum to bright white fluorescent light can promote plant growth, if you don’t care about energy consumption.

Delve into how the spectrum changes the way cannabis plants grow

Light is part of the electromagnetic spectrum, including not only the visible spectrum, but also X-rays, gamma rays and infrared light. Plants respond to the spectrum through a process completely separate from photosynthesis (called photomorphogenesis).

Unlike animals, plants cannot change where they grow. If their roots are born there, they are destined to grow only in this place, but plants can get maximum light by changing their growth direction and height. For example, sunflower leaves will grow in the direction of sunlight to ensure that they receive more sunlight, and put down the leaves at night to save energy. Like other plants, the growth of cannabis is also regulated by different spectra. According to the information provided by the spectrum, it provides the best growth mode for cannabis.

The “smell” spectrum of plants

Like animals, plants will feel the changes in the environment and make corresponding changes according to the changes in the environment. For example, animals can capture information in the air through their noses. Animals can track the smell to the outdoor direction and position according to the information captured by their nose. Although the nose can lead animals to track the smell for information, animals need their mouths to taste food, and their noses can only smell but not eat. Plants are almost the same. There is a photosensitive system in plants. This system acts like the “nose” of plants, which can capture information in the spectrum. Animals use their noses to find the direction and location of food. Plants use the spectral information captured by their noses to adjust their growth state and obtain the maximum amount of light.

Similar to animals, the “nose” of plants only captures the information in the spectrum, and can not obtain energy from the spectrum. A system similar to the “mouth” of plants are used to obtain or remove energy from the spectrum.

Plants get energy from the spectrum

Plants can obtain energy from the spectrum. They rely on chlorophyll and carotene in plants, which can produce photosynthetic elements. These elements are equivalent to the “mouth” of the plant. Chlorophyll absorbs sunlight through photosynthesis and converts light energy into bioenergy, providing material and energy for plant growth and development.

Like animals, plants are picky eaters. Not all colors of light can produce photosynthesis. Only a small amount of visible light can produce photosynthesis in plants. Most light has little effect on plant growth, among which blue light and red light are the most easily absorbed by plants. If you want LED cannabis lights to be more efficient, you’d better use red and blue spectrum grow lights.

To get the best effect of cannabis, what should we pay attention to for LED cannabis light:

  • The power of LED cannabis light is more important than the spectrum. Increasing the light intensity is more important to cannabis growth than improving the spectrum. And the effect is more obvious and direct.
  • If you want to grow cannabis leaves, you should increase the proportion of blue light in LED cannabis lights. Blue light can effectively promote the growth of cannabis leaves.
  • LED cannabis lights can promote the growth, germination and flowering of cannabis by increasing the proportion of red light.
  • Cannabis grow lights are available in a small number of other colors. Although red and blue light can meet the light needs of plant growth, proper other shades can make the plant grow healthier.
  • As long as you use high-quality LED cannabis lights (such as MOKOLight led grow lights), there is no need to worry about the spectrum. If the growth of cannabis does not achieve the expected effect, please increase the light.

I hope this article can help you grow cannabis, and I hope your cannabis can thrive!


Written by ——
Scott Hughes
Scott Hughes
Double Bachelor's degrees in Architecture and Electrical Engineering, 5+ years of experience with LED lighting, intelligent moving lights, and conventional fixtures. Reach Me Now>>
Scott Hughes
Scott Hughes
Double Bachelor's degrees in Architecture and Electrical Engineering, 5+ years of experience with LED lighting, intelligent moving lights, and conventional fixtures. Reach Me Now>>
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