Light cycle

Just planted my babies and wired up the light (400W HPS), the lights about 2 feet away from the plant in my wardrobe. Anyway, I heard that when you 1st plant them its a good idea to keep the lights on 24 hours to start with, but how do I know when to change the light cycle? I dont want to over/under do it for fear of screwing them up.

Any tips/advice would be appreciated and thanks in advance!

18 hrs on 6 off for the veg state. switch to 12/12 to induce flowering.

you can change to 18/6 whenever you want to, some people even keep theyre plants in 24 hour light until flowering which is 12/12 12hours light 12hours dark.

i grow 12/12 from seed under HPS all the tyme... u dont have to go 24 or 18 12/12 is jus as good.