Most people flower their photoperiod strains on a 12/12 schedule to trick the plant into thinking the days are getting shorter and it needs to start it’s flowering cycle.
Autoflowering plants don’t rely on a shorter light schedule to start their flowering cycle and normally will start flowering on their own within three weeks to a month after germination occurs. This will even happen under an 18/6 or a 20/4 or a 24/0 lighting schedule.