Floros and increasing height.

I current have my plants under florescence lights These plants are in their 5th week and are current 5-6 inches tall the lights are approximately 1 inch above them. I am afraid they will not get the other 8-10 inches they need in the next 3-4 weeks so i can flower them. Now my question is will raising the lights to 3-5 inches away from the tops of the plants cause them to stretch enough to get taller without stretching them to much and stressing the plant?

**bump** **bump**