When it comes to light, most of it is white, and practically invisible to the human eye. When you see a rainbow, you are seeing light separated into its different waves of color, that when combined aren’t nearly as pleasing to the eye.
These different rays of light operate at different intensities, from very hot (red), to very cool light (blue).
Light effects humans and plants alike, and is essential to how living organisms take in nutrients and grow. This is why certain plants can only grow at certain times of the year. The sun needs to be in a certain position in order for plants to get the light they need to grow through their life cycle.
Now that growers have the option to move indoors, a lot of lights will try to replicate or mimic outdoor, natural light. Plants that are planted in the spring start with a cooler light from the fading winter sun that is great for their vegetative stages, as they are getting great amounts of blue light.
When summer starts to reach its peak, plants will start to get hit with much more red and yellow light with the sun higher and hotter in the sky. This tells the plants to start flowering as they approach the end of their cycle.
For indoor growing, starting with a more blue light can be beneficial for early stages, and transitioning to a yellow light will help round your plants off at the end. An additional option -and potentially simpler- is using one light whether a hotter blue or a more cool yellow throughout the entire process.
More blue will encourage plants to grow more leaves and stay short, while using yellow light at the beginning can create more space for the plant as it sprouts out more quickly. Knowing which light can provide you with the right spectrum is essential to growing your plants the way you want.