In this blog, we explore how green light affects cannabis and other plants, and how you can select lighting to maximize your growth.
Green Light and LED Technology
Many fixtures on the market favor a blue-red spectrum. Those fixtures exclude the middle wavelengths from the spectrum and rely on blue and red LEDs alone, creating an unnatural “purple” light. The design philosophy behind blue-red fixtures asserts that a heavily tuned “purple” spectrum is better for several reasons, as noted below. However, such a sharp departure from the natural spectrum of sunlight doesn’t yield the best results for cannabis.
Full-Spectrum LEDs or Blue-Red?
Greenlight also signals plant morphology. It plays an important role in mediating a plant’s responses to blue light, and it influences leaf growth and early stem elongation. By sensing the ratio of light colors, plants can tell if they’re in shade or if they’re receiving direct light, and how to position their leaves to maximize light absorption throughout the day. That’s because green light penetrates leaves more easily than other colors. When plants sense a higher green-to-blue ratio, they assume they’re shaded by other plants, and they’re more likely to elongate their stems to compete.
Far-red light is the last thing a plant “sees” at sunset, so when there are high far-red levels followed by a period of darkness the plant “knows” that it’s nighttime.
As just one example, during the spring and summer, more of the blue spectrum of light makes it to earth because the sun takes a more direct path through the sky.
(Make sure to get a light made for this purpose, not just any green light will do!)
What to focus on for best results when it comes to quality of light:
Red & Far Red / Infrared Light (660 nm & 730nm)
In this section we’re only talking about how the plant uses hidden information contained in the spectrum of light to grow better!
A germinated seed moves towards red light
However, keep in mind that different strains are affected differently by the color spectrum of the light. Some plants are barely affected at all while others might react much more strongly. It’s important to remember that the changes caused by light spectrum are relatively small (such as stems tending to grow longer) and many other factors drive some of the same changes.