Promethean: Yes plants absorb red and blue light the most efficiently however the kelvin rating of a bulb has nothing to do with the spectral output it produces. It is simply a *rough* estimate of how the light produced will look to the average human eye. You'd do well to be more concerned with what the spectral distribution of a bulb is and not the kelvin rating. Of course you should choose bulbs with a K rating that suits your eye. This is why people often mix good plant bulbs with eye pleasing bulbs.
