You need to simulate the sun in nature. you can use 24 hour light when you are rooting clones or sprouting. When your are growing in veg its good to use 18 on 6 off this gives the plants a rest and also time for root growth. Now when you want your budding to start change your light cycle to 12 on 12 off its good if you leave the light off for 24 hours when your switch cycles, this will help the plants hormones switch to flowering stage. For now go to the 18/6 get your light as close as you can with out burning your plant and then kick them to 12/12 to bud.
good luck