Lights with higher blue spectrums are best for vegging. The ideal range to shoot for is between 14000K - 20000K as they contains more blue which is the most important light spectrum for vegetative growth .
Color temperature, or
degrees Kelvin (°K), is a number assigned to a bulb to describe the
color of light it emits. The lower the number the warmer or more to the
orange/yellow side of the light spectrum is its appearance. The higher
the number the cooler or more to the blue side of the light spectrum.
The bellow diagram shows some °K examples and their corresponding colors:
Tutorial written by Oz Stoner for cannanation.com/ozstoners.com