Mimicking daylight hours

so growing photoperiod cbd kush destined for outdoors after hardening off - seedlings right now are indoors under lights. i want to mimick actual daylight length so when they do go outside the change of light wont affect them, last time i did that they were on a 16/8 cycle, and the shorter 14 hour day sent them to flower early.

question is - the 14 hour day at my latitude is sunup to sundown, of course it gradually gets light and gradually gwets dark later, so actually bright period is somewhat less - like 13 hours. hereas under lights its an immediate on/off and full brightness. so do go with more like 13 hour light or even shorter to account for the gradual light/dark that happens outside?

@surfgeo If you start them under lights at 13 hours a day, they might start to flower on you.
I started a couple of seedlings and a bunch of clones under a T5 light in a dome. Lights on at 5am, off at 11pm. During nice days (not torrential downpours like we get), I put them outside during the day if I can. After a week or two, they outgrow the dome and then they stay out to fight the elements.
I’d start hardening them as soon as you can…the days won’t be getting any longer after next weekend (altho they get hotter and more intense sunlight).
I’m probably more North than you are…Great White North! 49th parallel on the wet west coast.

With them being seedlings, a light schedule of 15/9 should be fine. By the time you get them outside the little bit of difference in the sun shouldn’t be a problem

Hey @surfgeo I saw on another thread you have 5 autoflowers starting…same ones? give them 20/4, autoflowers don’t go into flower based on light schedule, they go into flower whenever they feel like they are mature enough. Don’t worry about matching light schedules.

Edit…crap, just re-read your post…doing photos as well! Ya, 15/9 or 16/8 is good, altho I would still do 18/6 to get them a bit bigger sooner. How long is your season outside? I have to plan for early October harvest before the rains, maybe even end of September, so for me an early turning would be a blessing! My neighbour last year got squat off his 2 outdoor plants as they didn’t finish.