Why Does Blue Light Help Plants Grow?

(Last Updated On: January 16, 2021)

Erik Runkle, the professor and Floriculture Extension specialist, stated that “One might consider the blue light less efficient because of its shorter waveband, but it is considered equally effective as a green or red light at driving photosynthesis.”

The blue light acts as a growth regulator, and so this light becomes entirely desirable by the plants in the growing process, especially in the vegetative stage.

All you need to do is, provide a low intensity of blue light to your plants. It will fasten the growth and magnify the plant’s quality.

The Sum and Substance of Blue Light

Blue Light has a short wavelength of 400-500 nm. Our perception is about a waveband of 400-425 nm, which is even shorter than green light yet affects the plant’s growth equally as a red or green light.

This wavelength is in our visibility though it appears to provide dimmer light. Not only that, even a low intensity of blue light has comparatively a higher energy level and a significant impact on a plant’s vegetative phase.

Now, what if we say it has experimented that “Plants grown with blue light are usually shorter and have smaller, thicker and darker green leaves compared to plants grown without blue light.”

It is only natural to think, why is the blue light so hyped up then, as it suppresses the plant’s growth in many ways.

Agreeing to the fact, the answer to your question is, blue light is conducive in enhancing the overall quality and increasing the vitamins of a plant. Besides, it promotes the thriving phase and massively influences leaf’s coloration.

This is how blue light becomes an inevitable substance for the plant’s growth.

However, engaging blue light with a red light in perfect order somewhat takes care of the flowering phase too.

Plant’s Seasonal Changes Related to Blue Light

If you haven’t noticed, the spectrum that the sun sends to the earth is not always the same. In different seasons the offered spectrum changes. Based on that,  plants depending on the sun shift their life into a new stage and adapt the new arrangements.

In early summer and spring, when the days get longer gradually, more quantity of blue spectrums is offered by the sun. This available amount of blue light triggers the vegetative growth of the plants.

Similarly, in fall or late summer, the days start to get shorter while the surface receives more red and infrared lights from the sun. It initiates the flowering/fruiting stage of any plant.

The Linkage of Color and Temperature

The light’s spectrum can be measured by Kelvin temperature. Generally, the blue light’s Kelvin temperature starts from 4000K and goes till 6500K.

To be more specific, from 4000K-5000K, the light refers to noon daylight where the visible light contains slightly blue color with the beginning of cooler temperature.

The right after range from 5000K-6500K, blue light is often compared to the white daylight, which is considered as natural light or cool white.

However, the latest technologies allow us to work with ultra-daylight of 10,000K. Not only that, more than 20,000K light replicates are used underwater for different types of algae in corals and marine macro algae.

How Does Blue Light Work on Plants?

If you are still confused about the effect of blue light on a plant’s growth, let me take you deeper and explain how a blue light works on plants.

Blue light is absorbed by the plants promptly. It mainly works on the “Stomata” of a plant’s leaf. Now, what is Stomata?

Well, stomata is the stem in a plant and uncountable pores in the leaf’s epidermis. It simplifies the gas exchanging throughout the whole process of photosynthesis. But how?

These pores continuously open and close while receiving Carbon-dioxide and releasing Oxygen. This part exactly is utterly essential to occur if the plants are performing an effectual photosynthesis.

In summary, it can be said that blue lights regulate the leaf’s stomata which in the long process initiates effective photosynthesis and helps the plants immensely to grow healthy.

Balancing with the Red Light

Blue light is unimaginably effective if it is combined with red spectrums. Not to mention, the vegetative phase does not ask for the red light as much as it demands blue light. Still, in the long run, balancing these two spectrums, hands down become the most beneficial light for the plants to grow in its best version.

Being said that, let’s not forget an exception can be seen in a few plants where the plants grow better under red light in the thriving stage.

However, tropical and foliage plants require a minimal amount of light where no strict demand of any spectrum is noticeable. Also, some plants flower all year without being controlled by one specific light color.

Frequently Asked Questions

Why does blue light affect plant growth?

Different lights enhance the plant’s growth with various advantages. Blue light reflects an essential impact on a plant’s growing cycle. This light is promptly absorbed by a plant and also speeds up the photosynthesis process. That is why blue light seems to affect a plant’s growth.

Why is blue light most effective for photosynthesis?

In the vegetative stage, blue light provides the right wavelength and temperature. So the plants effectively perform photosynthesis with the help of blue light. As the plants quickly absorb this light, it is said to be the most effective for photosynthesis.

The Verdict

Blue lights indeed hold the influential spectrums that make the plants comfortable to work with. Different lights have several responsibilities, but the role of blue light is inescapable even if the amount of it in the actual process is minimal.

In the case of growing plants indoors, it is crucial to provide an accurate light spectrum. In this way, you can both see the growth of happy plants and save yourself the unnecessary wastage on other lights while experimenting.

Leave a Comment

Your email address will not be published. Required fields are marked *

6 + 4 =