Plants thrive best under a mixture of blue and red lights. The perfect ratio being around 1:5, blue to red. However, it varies depending on the plant and the growth stage. As plants absorb a certain amount of energy from all light colors, the absorption rate can vary with different colors, so will the plants’ growth.
The cause of this variation is due to the different wavelengths of various light colors. Depending on wavelength height, the plants will absorb the energy accordingly.
A proper light spectrum is necessary for photosynthesis, which supports plant growth. Before you buy a fixture, be sure to look into the available spectrum. Switches featuring a full spectrum are ideal options for your growing room.
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Does The Color Of Light Affect Plant Growth?
Under low light intensity, light maintains a significant impact on plant growth. The effect is most evident at a relatively low or moderate light intensity, while red and blue light works best. UV light is especially detrimental to plants, causing leaves to burn. Growers often use fluorescent lighting to enhance plant growth.
- Violet light in the 400 – 520 nanometer range stimulates chlorophyll absorption and photosynthesis, and promotes growth.
- The 610 to 720 nanometer red light range promotes blooming and budding.
Plant Growth Under Different Colors of Light
1. Purple or Violet Light
Purple or violet light shades have the shortest wavelength than all the others, and thus they have the highest energy.
During photosynthesis, plants readily take in a high amount of these lights, and their shades play a big role in plant growth during the vegetative phase.
Violet lights enhance the plants’ leafy parts’ development and growth and produce vegetables and fruits of good taste and smell. Moreover, plants produce more antioxidants in their body in the presence of purple or violet lights.
2. Blue Light
Plants happily absorb blue lights due to their short wavelength and high energy potential. These lights are the most essential during the initial stages of plant growth since they help the plants to generate more chlorophyll in their leaves, which helps them absorb more light afterward.
During seeding, plants need to absorb a huge blue light to enhance healthy roots and stems and ensure rapid leafy vegetation growth. Without sufficient or a healthy dose of blue light, the seedlings may fail to sprout out together from the ground.
3. Red light
Red lights give the longest wavelength in the color spectrum, and thus they have the least energy. Red and orange shades play a major role in plant growth, and their presence is essential during the blooming and flowering phases of plants. Furthermore, these lights prevent the chlorophyll breakdown, which allows the plants to absorb additional light and retain energy for further growth.
While these lights are not needed in the initial stages of plants’ growth cycle, when blue and red lights are combined, they significantly impact the production of large and healthy leaves.
4. Green Light
Most of the plants have a green color. They absorb all the colors in the light spectrum (red, blue, violet, yellow) while reflecting the green one. Thus, only the green light is reflected in your eyes.
Even with the low amount absorbed compared to the other lights, green light facilitates chlorophyll production, which helps with photosynthesis while providing the plant with a greener color.
The green light has one significant advantage when it comes to cannabis plants. Since cannabis plants cannot absorb green light, it does not interrupt the necessary dark periods. Utilizing green light lets you work on your plant when it is supposed to be getting no light.
5. Far-red Light
While only little absorption occurs with this kind of light, it plays a significant part during plant germination and flowering. Far-red and red lights concur in regards to the effects they have on plants.
A normal plant has a phytochrome system that regulates its growth, changing itself depending on the kind of light it is exposed to.
There are two main forms of protein in this system; biologically inactive (Pr) and biologically active (Pfr). When a plant receives the red light, Pr changes into Pfr, and when a plant perceives the far-red light, its Pfr transforms back to Pr. Pfr is essential because it fosters plant growth, though it slowly changes back to PR over time if the plant is placed in the darkness. However, a plant’s vegetative growth and flowering are highly influenced by the Pr to Pfr ratio.
An instance of how the far-red light properties may benefit you to have optimal yields can be seen in cannabis growth. In the day, these plants show the most flowering, while during the night, they ripen. Being a short-day plant, it often requires 12 hours light exposure and 12 hours darkness exposure.
6. Yellow Light
Yellow light rarely has any part to play in plant growth. Eliminating yellow light can produce healthier plants compared to plants that are exposed to it.
7. Natural Sunlight
Natural light comes with a whole spectrum of colors, giving all light varieties from violet to red shades. It is free and limitless, making it the most feasible option for plants to absorb more energy and thrive rapidly.
Unluckily, not all plants nor regions around the globe have the same access to sunlight due to geographical, seasonal, and climate change. Therefore, the plant growth rate becomes limited or stunted in such cases.
But luckily, because of technological advancements, you can now give rich spectrum of light to all parts of the globe through artificial lighting. Here you can learn more about all types of grow light.
Signs of Poor Lighting in Your Plants
Although different plants’ species have different peaks, losing that optimal intensity can impact your plant growth.
Excess Light
While plants tend to thrive better with an increase in light intensity, several issues may arise when the light becomes excessive:
- The leaves folds and the edges turn brown or brown spots appear.
- The plant loses vigor during the hottest hours of the day.
- Small leaves lose the green color and become whitish.
- The plant turns its leaves toward the opposite direction of the light source.
Insufficient Light
While excess light can cause harmful impacts on plant growth, lack of light can also hamper the healthy activities in plants.
Low light intensity lower plant metabolism, limiting chemical and physical activities within the plant body, which can lead to several problems:
- Leaves turn yellow and fall.
- Plants rarely bloom, and if they do, the flowers are partially developed.
- Plants develop colorless, long, and thin stems with little vitality and a huge distance between the inter-nodes, extending in search of a light source.
- Plant development is slow and weak.
What color light is best for flowering?
Red lights of 2000K to 3000 kelvin and deliver radiation in the range 640 – 680 nanometers are most important during the flowering stage. This light source promotes stem growth and overall plant height because red light indicates that there are no other plants above it that provide for unobstructed growth.
What color light is best for seedlings?
Blue light with a Kelvin temperature of 5000K to 6500K or wavelength in the 400-500 nanometer range should be applied during the vegetative stage of the growing cycle and when beginning seeds indoors.
What color light helps germination?
Thompson & Morgan reports that the color in the red-green spectrum helps the seeds to germinate, whereas the blue spectrum inhibits it. Since red light causes a plant pigment, phytochrome, it contains, while blue light only inhibits its effect. Light that is shaded has similar results.
What color light is best for photosynthesis?
A combination of blue and red light is what helps the most for photosynthesis. This is what led to fluorescent lights being used in greenhouses; they are really energy-efficient and use less electricity than regular light bulbs!
What color light is best for succulents?
Red and blue lights are what succulents need the most. If you live in a cold, wintery area, then your succulent plants will want to be under red lights for most of the winter.
Summing It Up
The color of light needed during different growth cycle stages is crucial to address to obtain optimal yields. While violet, red, and blue lights are a must for the plants, yellow and green shades are ineffective.
Light intensity and the kind of light used can also lead to variable harvest. So, it is important to find the ideal balance in all these factors if you want to achieve optimal growth from your plants.