" do you use white leds? "

Yes.
For flashlights.
They are jus' peachy for illumination.
As grow lights, they leave much to be desired.

The ones that use phosphors are almost useless as grow lights. (A look at the spectral curve may prove illuminating.)

And the R.G.B. kine, grow just as well with just the R. n B. and no G., see?
So, If I put the power that is wasted on G. into producing more R. right around 652 - 657 nm., I am a-head by several centimeters and a ninth of a furlong..

Seriously, you are better off with CFLs if you wish to use "white" light.
They are actually more cost effective than white leds, all costs tallied.
Unless, of course, I'm completely wrong about that.:stoned:


Aloha
Weezard