" But apparently red light is used to bring MJ plants to bud ? "
That is probably the sales pitch. But plants all across the globe manage to come into bud in just plain sunlight. My zinnias do fine indoors in white light.
Clandestine marijuana growers who had grow rooms indoors, and sometimes underground, had to provide all the light artificially and their electric bill was a critical issue. So they could save money by just providing the absolute minimum of spectrum, consisting of just red light and blue light. Apparently blue supported the vegetative phase and red supported the flowering phase. But, in my opinion, home growers don't have to adhere to that red light thing.
ZM
