How to force flower after 12/12 from seed?

I started two Northern lights from seed at 12/12 and they are doing wonderful, around 12 inches tall at a month+ old. the only problem i have is that they are growing straight up and getting rather big. in normal situations to start the flowering stage one switches the lights to 12/12 but how do i induce flowering on seedlings started on 12/12?


should i give them an extended period of darkness?

they do not show any sign of flowering aside from pre-flowers. they are beginning to branch out so my guess is it still wants to grow a bit more....


tanks

I think that you are doing the correct thing. Just keep it under 12/12...it should start flowering soon. I've never personally grown from 12/12 but i believ the plants have to grow enough foliage and a strong root system before hand, and then it should start to flower...

Current grow
https://www.rollitup.org/indoor-growing/442573-1600watt-feminized-cheisel-vanilla-kush.html

Last grow - finished 1.5LBS
https://www.rollitup.org/indoor-growing/406006-1000watt-feminized-barneys-farm-violator.html

Shutting off the lights for 24 hours should do the trick. But if it doesn't or you are looking to veg it another week anyway, you might try switching over to a 18/6 cycle for the next week, then reducing to 12/12 after 24 hours in the dark.

Sorry but seems like something like that ^^^may cause hermies to me(JMO)...Just leave her be bro shes just getting as big as she needs to she will start within a week would be my guess...GL

ones the plant gets big enough it will go into flower like dopeedog said so dont chance anything...its gotta get strong enough to support the weight of the buds