One thing I learned from screwing with leds, is that adding or subtracting different parts of the visible(as well as invisible-ie-infrared)spectrum, you really can control the will of the plant.Adding alot of red-630-660nm-will stretch the hell out of your plants.Alternately, adding blue-440-470nm-will stop the stretch, dead in it's tracks if enough is applied.But dont get me wrong, I was not impressed with current led tek's ability to flower cannabis.I actually wish I kept at least one all red, and one all blue ufo-just to see what happens if applied in certain situations.