I'm in my 11th week and have stopped adding n...

Hi @Jlbgrow! Pistils can be a clue, if you noticed that new pistils have stopped appearing and old pistils have almost all turned red and curly, but the best way to ensure it's the right time is to look at the trichomes with a magnifier/microscope. Clear/Transparent/Skinny trichomes mean it's too soon, Milky/Cloudy/Fat trichomes mean the harvest window is open, Amber trichomes mean the harvest window is ending, and THC is degrading but CBD/CBN components are exploding. If you don't want a couchlocking effect, you should harvest once the first amber trichomes appear (5~10%), most of the trichomes should be milky/cloudy but not clear. Flushing for 2 weeks is a good thing if you're confident you gave enough P+K earlier to ensure the maximum growth for your buds. You can still give some sugar/molasses during the last days. Hope this will help, let me know in the comments section if you need any further information. Enjoy your harvest! 👊