I would toss a few more bulbs in there if you can to spread your light out a little bit more evenly. If you analyze the pictures and what the plants are telling you, you can see they are each reaching for a centrally located light source. Kind of think about a room full of moths with one light VS a room full of moths with multiple lights. Drop a few more bulbs in there or make a box and line it with some sort of reflective material (careful as tinfoil can burn plants)
Also when it comes time to transplant them, transplant them deeper into the soil so that stretch doesn't become to much of an issue. I had the same problem and that seemed to fix it right up.