The color of grow light DOES affect plant growth, but the effect is more noticeable under low light intensity. Red & blue light are most effective for plant growth, while yellow & green have minimal effect. UV light can damage plants, causing leaves to burn. Growers often use supplemental light to optimize plant growth.
What effect does the color of grow light have on plant growth?
When plants are just seeds and are first sprouting, blue light should be used.Blue light is very important to the beginning of plant growth because it increases the amount of chlorophyll that is formed. Some seeds won’t sprout without blue light.Red light and blue light are important when the plants are mature and beginning to flower.This helps them produce more leaves and more crops.Violet light can is used at any point in the plant’s life to enhance the color and taste of a plant.
Ultraviolet Light
Ultraviolet light, also known as UV light, is commonly known as being harmful for humans. If a human is exposed to too much UV light they will get sunburned and can have other negative effects. Just like prolonged exposure to UV light is harmful to humans, high-intensity or long exposure to UV light is harmful to plant growth. The less exposure to UV light, the better your plants will grow.
Violet Light
Violet light is beneficial to plants. Violet light has a higher amount of energy so when plants are exposed to violet light the plant color, fruit and vegetable taste is enhanced, the plants have a better aroma, and increases the amount of antioxidants that the plant produces. So overall, violet light helps plant growth, and can be used to protect the plants from damage.
Blue Light
Plants benefit from blue light primarily during the early stages of growing. Blue light helps with the plant’s production of chlorophyll–the green pigment that traps light energy and is integral to photosynthesis. In other words, blue light is easier for a plant to absorb and use the energy in photosynthesis. So, blue light increases plant growth and makes the plant reach maturity faster. This is why blue light is especially important for seedlings and young plants. Exposure to blue light can help the seeds germinate, and ensure robust growth for roots, stems, and leaves.
Green Light
Plants absorb many types of light but reflect green light. This is why plants typically have green leaves. Mostly green light is used to enhance the production of chlorophyll making the plants greener. While green light isn’t as integral as red or violet light to plant growth & health, green light can make plants appear greener, and therefore is useful in commercial greenhouses where customers are viewing & selecting plants to purchase.
Yellow Light
Yellow light is similar in its effects on plant growth & health as green light.
The major difference yellow light has as opposed to green light is that, while yellow light doesn’t directly help produce chlorophyll, some studies have shown that removing yellow light from greenhouses may produce healthier plants than growing the same plants outside, where they’re exposed to full-spectrum sunlight.
Red Light
Red light carries less energy than the other colors and is not very effective on its own. But when combined with blue light, red wavelengths are very helpful for mature plants. Red light helps flowers bloom. When combining red and blue light, the amount of leaves that a plant grows is greatly increased. Specifically, a study by Expert found that if plants are grown only using red light, they’ll have a stretched, enlongated appearance, and their leaves will become thin and large. Adding 10-20% blue light allowed plants to grow much healthier, with a compact appearance.
There is also far-red light which is has wavelengths that are lower than normal red light–similar to near-infrared wavelengths. Far-red light helps the plants produce greater yields. The far-red light does this by speeding up the process a plant goes through in the night.
