There's alot of red in that panel, hence the stretch. Sorta what happens if you used HPS at that stage, plants "go to the light".

If you had a LED light that used mostly blue it would be a different story. But like I said earlier, cost wise I don't think it pays. One simple T5 either 6500K or like I promote super actinic white, so blue it looks like a blue neon tube compared to 6500k even.

Blue light stimulates the hormones that cause the plant to root.
Here's a couple of pics of my clonner/seedling light, the blue one is the actinic and usually run that one by itself for the first week or two.