pluck out some of the obviously week ones. then you will get some males, that will make some space later. i did this on purpose the last time i grew outdoors so the wouldnt get too tall and be visible. they dont get bushy that way either. from being crowded they were like 2 ft sticks with buds on them. i only got about 3 oz from 12 plants. this yr im going the other direction, single plants with all the room they can handle and tying them down if they get to tall.