Flowering Stage

Plants will not switch to flower immediately when on 12/12, they need to be mature first. and even then it takes them a good 2 weeks to build up enough flowering hormones to do it before we see signs of it happening. Its why when you grow photoperiod seeds on 12/12 seed to harvest, they do not bloom once they sprout as they have to hit their maturity first. think of it like plant puberty, babies cant have kids till they hit puberty and sexually mature. Autoflowers are different and do what ever they want. kinda freaky mutants. they can bloom from a week of being alive. Good Luck!

Hello taikonaut, the plant is stretching already (pre flowering). But the only reason for a cannabis plant not flowering after switching to 12/1 could be a disrupted night cycle. So check any light leaks, but also the timers on your lamp for example. If it turns on for a short amount of time during the night it will keep the plant from flowering.

You need to check if there are some others lights during her night, including tent's light leaks. She needs a complet darkness cycle of at least 10h to go blooming. Good Luck !

some takes longer, make sure you have no light leaks and plant has 12 hours of full darkness. by look its in transition mode. be patient. all should start soon