The plant is fine... Why do you want to make it taller? The plant will grow quickly enough when you start flowering. If you want the plant taller just wait an extra week in veg' before flower. I made the mistake of stretching a few of my first crop, and the yield off these plants was terrible. I'm on my second crop now and anywhere I see stretching, I top the little bastards. On this second crop we're aiming to keep our plants below 3 foot, we're going for maximum yield on bud, not plant matter.