Can't imagine there is a problem with insufficient lighting as I have been using a 315 LEC at 22" above canopy. I use Cfl's for the first 7 to 10 days then switch to 315. It isn't part of "finishing" process as browning starts around the same time flowering begins. I have had several successful photo grows and tried my hand at autos after reading all the aculades here but my luck with autos has not been positive. This grow is the last of my auto seeds so I am going back to growing photos to see if that could be the issue. I am out of options if that doesn't work.