Awesome photo, awesome grow. You need to check your trichomes, with a hand held microscope, you should not harvest until the trichomes are at least 50% cloudy, 50% clear. With the trichomes at 50/50, depending on the strain your growing, should a head high, wait alittle longer for the trichomes to turn amber, a couchlock high.
Some growers go by the color change of the pistils, but radio shack has the hand held microscopes for about 15 bucks. They are worth every penny, trust me. BTW, my 1st grow I used CFLs all the way, had a sweet yield