[RabidRabbit]

From what i have read and observed from a few years of steady extracurricular research is that marijuana plants are best able to utilize red and blue light (i cannot recall the specific frequency ranges). Blue light has been shown to result in shorter inter-nodal lengths (possibly because of triggering the plant to produce higher amounts of giberillic(sp?) acid) and red light has been shown to trigger/quicken the onset of fruit production (BUDS!!!). Most all frequency's of green light are useless and are reflected - this is why we see most plant matter, in this case marijuana, as being green.

A simple experiment could validate any of this. For example, try growing one set of plants from seed/clone to maturity with only a metal halide (more blue), one set of plants with only high pressure sodium (more red), and one set under metal halide for the vegetative cycle and high pressure sodium for the flowering cycle. As has been proven time and again by growers around the world, the latter of the three is the method of choice for experience growers who have tried it all - I am inclined to believe that there may be something to this!

to each his own, and to all a good grow,
cheers