Vegetative to flower

[420soul]

Hey, all. I have 3 plants in the vegetative cycle since the last week of September. I have them under T5 fluorescents from 5am to 11pm. I'm going to put them into the flowering cycle under a 400w HPS lamp.
What I'd like to do is change the light cycle from 6pm to 6am. Can I do that? If so how long should I leave them in the dark before I change them to the 12/12 cycle?
Thanks for any help.

 

[Be Irie]

Instead of turning them on @ 5 then turn them on at 6:00AM and turn them off @ 6:00 PM and you are set...

 

[420soul]

Thanks, Irie. How long do I need to put them in the dark for to induce flowering? 12 hours,24 hour,ect?

 

[Hydroguy]

some say leave them in the dark for 24 hours, me i just change the lights to 12 hours, plants know what to do,, nature is smart like that!!

 

[Screwnuts33]

Some don't put them in the dark at all, some do a 24-48 hour dark cycle before going 12/12. I haven't read anything that shows one way is better than another. I do think a little nap before going 12/12 can't hurt though.