Unfortunately this is another false assumption made by almost everyone, and that is exactly why the comment challenges everything you've read on the subject. What you have read was not written by folks who investigated the specific function of plant pigments. They were told what to think and what to write, so they thought it and then wrote it.
The light harvesting mechanism of plants, algae and some bacteria, such as BGA consists of a central Chlorophyll complex. The complex, has, among many other components, a series of auxiliary pigments which respond to wavelengths of light other than blue and red. The energy captured by these pigments are then passed on to the Chlorophyll and therefore act as a spectral extension of the main Chlorophyll response curve. The leaf analyzes the spectral distribution and fabricates a variety of pigments to perform tasks, such as to reflect wavelengths that have too much energy, to absorb wavelengths that are not primary wavelengths and some pigments are even capable of changing the incident light to another color and reflecting it on to pigments that can then absorb the new color and pass it's energy on to the Chlorophyll.
It's a very sophisticated system and it doesn't need your help. Whatever spectral distribution you provide, the plant will determine how to best use that energy. In this hobby, it actually the opposite of what folks think. There is actually far too much light, that more often than not overwhelms the plants ability to quench the excessive energy.
So there is no demonstration that plants "...absorb light mostly in the blue and red..." It's simply that the Chlorophyll pigment itself has a higher response to blue and red but it depends on the other pigments to absorb the remaining wavelengths and to process those wavelengths. On the contrary, it is specifically because the Chlorophyll pigment has such a high response to blue and red that is is easily overwhelmed by blue and red. So if anything, what the photosynthetic spectrum shows is that you should be using LESS amounts of blue and red to reduce photo-inhibition. This fact has been completely misinterpreted for far too long.
Spectrum loving Klingons are a plague, a pestilence of misinformation on this planet.
We are the cure.....
Cheers,
