turning the lights off for 24 hours isn't going to show you anything. It takes a little more time (about 1-2 weeks in 12/12 cycle) to show signs of sex. Maybe your friend meant when you are ready to flower your plants (when they are at the height you desire) that you should cut the lights for 24-72 hours. This is supposed to help induce flowering...

It's also been recommended to do this same process at the end of your flower cycle right before you harvest. Turn the lights off and let the plants sit in the dark for 24-72 hours. This is supposed to push out resin and make the buds denser. I've tried both methods...can't say I've seen a big difference, but then again, it didn't hurt.....

You gotta find what techniques work for you....good luck! :jointsmile: