Buy a cheap light meter to see what your receiving, but my educated guess would be that your not getting enough. I would bet that the window is your supplemental lighting.

I've seen some nice buds grown with just the 90w ufo. But I would just build your tent now, when flowering comes around your going to have to board or black out the windows somehow anyway.

You might want to reduce that room down to 4x4 or so. But I'm not a LED lighting expert. :rasta: