12/12 puts them into flowering, so I'm assuming that if you're controlling 12/12 then the plants are indoors.
I grow indoors in a tent, and I found when I closed it up for the night with lights off, the humidity in the test rose astronomically. To 95% R.H. It became really obvious very quickly that as soon as the bud starting packing on size, it was a perfect grow medium for mold. I immediately bought a dehumidifier, which was expensive to me because I had paid so much for all my equipment I didn't want to be dropping $150 on a dehumidifier. But I'm really glad I did. I had spent two months growing two males, started again and got two females, but this "project" had now taken 6 months of my life with nothing to show for it if I had allowed mold to enter the picture.
Every night that dehumidifier pulled out 5 or 6 cups of water from my tent! And it ran hot, too, so I had to position it at the door and seal up around it with towels -- that way the dehumidifier vent could pull from the tent while the heat exhaust from the unit exhausted in my room. It was a pain, but totally worth it as I never had a problem with the dreaded mold.
So watching your nighttime humidity level is pretty important. Don't over nute. Don't try too much manipulation at this point. Don't cut fan leaves. That's about it if you're indoors. If you're outdoors, watch for garden pests and have a plan of action that doesn't involve spraying your grow with chemicals.
Oh, and don't pull too early or leave them going too late. Good luck!
