Was there a particular reason you decided to flower them so soon? Also, should have really been no nutes until the plants were asking for them (usually the leaves will start to become a lighter green as an indicator)- let alone a 3oz. dose to a gallon. You will for sure get some repercussions from the OD. I've never used anything but Foxfarm nutes and I've never given anything over the recommended directions (3-4 t)- usually always less than the directions. marijuana usually for the most part is not a heavy feeding plant, some indicas can take some heavy feedings though..

A flush can cause more problems than it would fix- though I think you might make a right choice here, def. nute and salt build up in the soil with the plants so young.. eck. but the flush will take everything good out of the soil. How many times have you nuted the plants thus far total? What color/ how murky is the water coming out the bottom when you water?

Btw, I've seen more people hurt plants with fertilizer then help plants- easy does it...