auto not flowering

I honestly don't have a good answer for you. I know the depends on the genetics and unless you've got a few grows with one batch of seed of one variety it's really hard to tell if you need to switch the light or just wait a bit longer. I have switched one at 60 days to 12/12 light and it did flower and produce well. To offset for the shortened light period I cranked the light up as high as I dared which was a risk but I feel it worked out. Overall the overall grow period was a bit long and approaching photo's. Still I love auto's. I can turn them more quickly and have greater variety and I get good yield from them.

Some autos can take 9 weeks plus before they start. That and needing 18 hours light for all the flower time cost to much money when your running good lights, ac, fans, humidifiers, dehumidifiers, the little bit of money saved in ferts isn't justified to me. I stick with photos and save time and money. Cheers