help im a noob

hi im new to this site, and new to growing, i have 6 black jack (ladies), which i vegged for 6 weeks till they were about 12inches under 4 55watt sonlite flo's, and they are in week 4 flowering, under a 400 watt hps. i have a extractor fan and a carbon filter. temps are good down there too, 26 degrees. this might sound really dumb, but how long left now? about 2 weeks or longer? they dont look 2 weeks from finish? do i stop feeding them nutrients now? and about how much yield? or cant you say. ill get some pics up soon. thanx

flowering takes 8-10 weeks and dont feed any nutes for the last 2 weeks to flush them.
so stop nuting at 8 weeks.
check your thricomes and pistil colours for your harvesting requirements.
(heavy stone or heavy high).