The pistils of my plant have turned brownish at their tips at only the start of 5th flower week. There have been harsh winds, rains and some hail here so that could be the case. Google says Brown pistils means almost ready for harvest but i doubt that's possible at 4 weeks of flower (not counting the stretch weeks). She's a Skywalker Kush from Reserva Privada that normaly has an 8-9w flower period