Man, sorry for all the stupid replies, supertiger, some people just can't resist jumping in every time someone has a new idea, just to remind them they should be doing exactly whatever everyone else is doing. It makes it worse when they clearly don't know what they are talking about.
Bulbs produce light by heating up certain elements, which give off different colors of light depending on which elements are heating up. The combination of these different colors appears as a single color to the human eye, and when a bulb is rated in kelvin temperature this is what is being given. It doesn't actually describe the individual colors of light that are being given off, and this rating is more or less irrelevant to plants.
Obviously these bulbs are ridiculously high in blue light, which is known to veg plants and produce trichomes. Only concern would be too much UV light, I've heard these produce a lot, so do your homework and be very very careful.
Actinic bulbs operate entirely within the blue spectrum, and the word with some of the more experimental growers is that these lights are the shit for vegging, but that you should supplement with another kind of light to fill out the spectrum a bit. Haven't seen it implemented in person, but I'msure we'll be seeing a lot more of them in the future, though the high UV may make them more suitable to UV production than veggings. If you experiment with these would appreciate a heads up, as (I'm sure) would some other members. Don't get cancer!
