If the plants that you are growing are in a go slow mode then you may need to upgrade your lighting system.If the light that you are useing is a 600/1000hps then you have some other problem nutrients or something wrong in the grow room..........................tyke............................
make sure your lights are at the correct distance for the stage in your grow and also keep your nutrient solution at the correct ppm and of course just keeping your plants at proper temp ... best of luck
good enviroment 68-80 humidity% for flower 30-50 for veg 40-70, good consistent feeding schedule, good pot size, topping, tying down (LST), cO2..lots of shit