Typically, 6500K is about the max you'll find. Getting much higher than that will get you in the UV range, and area you don't want to go. This article I published on NGA/ATP might be helpful, Lindsey.
http://garden.org/ideas/view/d...
You can also use the (more standard) 4500K fluorescent tubes or a mix of the two spectrums in a 2-tube, shop light. The 4500K will help more with flowering whereas the 6500K will help more with plant growth. But this is not an exact science. Plants will grow under 4500K lamps and will flower under 6500K lamps. Have I confused you enough?
