When grown outdoors in the sun, the light spectrum received actually provides the cannabis plant with a wealth of information about what is going on in the world around it. During spring and summer, more of the blue spectrum reaches the surface. In summer, the plant responds to this bright, direct light (with a lot of blue light components), prompting it to grow vegetatively with lots of large leaves and short stems. The plant tries to spread as much as it can and increase the mass of its leaves.
Blue Light - Grow lights with a higher ratio of blue light are often used in the plant growth stage as they tend to keep cannabis plants short and strong with large, healthy leaves.
As autumn approaches, the sun begins to drop in the sky. As a result, more of the light reaching the plant falls within the red spectrum. More light in the red part of the spectrum indicates that the plant is coming to the end of summer and it's time to acclimate before winter. When a cannabis plant is exposed to a higher percentage of red light, it responds by growing a longer stem with more space between the leaves, and grows as high as possible to its best to begin with Germinate and pollinate by the wind!
Yellow/Red Lights - Grow lights with lots of red are often used during flowering to encourage plants to grow taller (stretch) and help encourage budding. Under red light, plants may enter flowering more quickly than under blue light.
By tracking the ratios of colors in the spectrum, the cannabis plant is able to "learn" what's going on around it, helping the plant grow in the best way possible!
with more blue spectrum components are recommended if you want to keep plants short and leafy. Switching the plant to bloom can switch the lights to the parts where cannabis likes more reds and oranges during bloom.