Transition....24hrs darkness??

So what is the best way to transition from grow cycle to 12-12? I have heard several views. Just throw em' in. Gradually reduce the light over a few days. OR 24 hours of darkness....thanks for your help

I personally give mine 24 hrs darkness in a closet. I do this cause my ballast is a switchable one, so therefore when i put them in darkness for 24 hrs that gives me time to setup the hps and get it running and adjust temps and humidity. I'm sure you'll here alot of different ways to introduce the 12/12, but whatever works for you is what is good.