Your lights are facing the wrong direction... optimally they're like floro tubes... the series of ridges pointing at the plants. You also have no reflectors... you're losing a 30-40% yield increase with no reflectors! Also side-light them. If you got space put a light or two in the middle of plants, surrounding the light(s). To coin an analogy, make your plants a donut-shape, and your lights the grease(cover uhm!) Or surround the plant; one on each 'side'(pick a number greater than 2, triangle, square, pentagon, etc.). Y-splitters work great for this. As they make hanging CFLS cast a lot of 45 degree light, as your leaves are hanging around that angle, parallel to foliage is best!
Also 6500K supplemental or even 1 to 1 would be ideal. 2700k are 'powerfully weak' in the blue spectrum.