the weather in my part of germany is really bad for this summer at the moment. it's raining too much. i've put them in a dry place to prevent mould from forming. maybe they're not getting as much fertiliser. they'll get one more week and then they'll be harvested.
@IvyGrows, sure, i could gave it two more weeks, but most of the cola are at the stage i want them to be. i checked the trichomes with a 60x magnifying glass