12/12 light from seed?

I am doing a pc grow and I have heard that doing light cycle from to 12/12 is not bad. And that the plant will think fall is already here and what not. So is it a good idea to do that light cycle??

This is the way to cut veg time down to just what the plant needs to go into flower. You should start seeing "pre-flowering" as early day 20. It will not hurt the plant and it will stay as short as it can. You still have to think about the characteristics of the strain you select. Most plants will grow about three times their height from flower to harvest time.