flowering

Ok all, quick question. When I decide it's time to flower, do I need to give the plant 24 hrs of dark time before I hit the switch for 12/12? I am currently on Day 32 of veg. I am doing 18/6. But I seem to have read somewhere about a dark period before flowering? Is that true? Any info would be helpful! Thanks!

it's not needed, but if you do have a 24-36 hour dark period prior to switching cycles, it helps the plant transition from vegetative to flowering quicker, and can reduce overall flowering time by up to a week