Modifying current on/off light schedule so plants "wake up" when I go to sleep

Good morning all! I have a question about light schedules that I think I know the answer to, but looking to confirm.

I currently have a group of girls in veg where the lights come on at 5:30am and go out at 11:30pm. Ultimately, the goal for this group and future groups of plants is for the lights to come on at 9pm and turn off at 9am for flower tent or at 3pm for the veg tent.

My initial thought is to just leave the lights on for a 24hr period and shut the lights off at the next “9am” to begin the 12/12 flowering cycle.

For example, lights went on today at 5:30am → on on on on on → OFF @ 9:30am → ON @ 9:30pm —> I’m flowering, pistils, buds, trichs…


When the lights go out at 11:30 PM, let them stay in the dark until the next 9:30 PM comes around (22 hours later.) Your girls won’t know the difference.

What you laid out in your last paragraph (5:30 AM to 9:30 AM on and then off for 12, back on at 9:30 PM) should work fine too.


My understanding is it is better to have an extended dark period before flipping rather than an extended light period :v:
Looks like @MidwestGuy beat me to it


I remembered this right after I hit the reply button. I’ve heard the same. I would go for the extended 22 hr dark period.

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Especially in flower I would think.


Group hug. Thank you so much!!! Glad I asked!


This came up in another thread recently and there it was go for an extended night period.