Hello. I'm a grade 12 student working on a lab and my teacher doesn't really know how to answer this question. I was wondering why blue light cause plants to grow more than red light when red light, I thought, has the ideal wave length for plant growth? Everything I've read suggest blue light is best for plant growth but my research also seems to point to the wave length of red light (between 625-740 nm) as being best. Thanks!

Just a thought, if photosynthesis can only occur in the physical light spectrum, and IR is not enough and UV is too much, I would think that blue or violet light, having a higher energy density, would accelerate the photosynthesis process the most.

Photosynthesis is really a process of breaking chemical bonds and moving ions from one element to another. This energy comes from the available light. The higher frequency lights have a higher potential energy.

I cannot promise this is 100% correct or all inclusive, but my theory anyway.

Plants look green because they reflect green, so green would be a bad idea. A very soft blueish light works best. This type of plant gowth bulb has some blue and some white. Plants do better under high frequency lights, ROYGBIV is the spectrum, eberything to the right of Green is best.