Why Do Plants Grown Under Blue Light Grow Taller Than Under Red & Green Lights?
- Visible light is vital to the health and growth success of most plants. Plants will take visible light and convert it to energy to power their vegetative and flowering growth activities. Of the seven different colors in visible light, plants use two of them the most: blue and red. However, the two colors aren't used by plants for the same purposes. A plant will use blue light to grow leafier and taller and red light to flower.
- It's a characteristic of plant life that plants take only those colors in visible light they need and then reflect the rest away. Light reflection is the reason why plants appear green to human eyes. Plants rarely make use of the green light contained in visible light, and it's of no use to them in growing taller or stronger. In addition to green, plants tend to use little orange, yellow, indigo and violet light, reflecting all away in varying degrees.
- In a plant, blue light is used to power its vegetative, or leafy, growth. Blue light can help a plant grow strong, in other words, which also means a plant can grow taller. Plants exposed only to red light without any blue light also don't tend to flower as fully. Green light is the least effective light for plants when it comes to growth. A plant that receives at least blue light and some red light will grow more efficiently.
- Blue light sensing in various species of plants is so particular that plants have specific receptors within themselves called phototropins. These phototropins actually help plants actually orient themselves toward a blue light-containing source, which is known as phototropism. Plant phototropins enable a plant to take in as much blue light as it can so that it can grow thicker, taller and stronger. Phototropin presence in plants helps to explain why some plants grow taller than others, too.
- Both natural sunlight and fluorescent light (known as cool white light) contain healthy amounts of blue light. Sunlight also carries a large amount of red light, which is also helpful to a plant. Fluorescent light carries a small amount of red light, too, and plants grown under fluorescent light do quite well. Working to give a plant enough red light, but especially enough blue light, will help it to grow as best as it possibly can.
