When to start pre harvest flush

You still have 3-5 weeks of flowering to go, so keep feeding until about 90-95% of pistils are brown, then give plain water for the last 7-10 days before harvest at around 98% brown pistils. At this stage your plant still needs good nutrition for proper flower growth. Whatever they say on the packets/web site regarding maturation times is generally BS and based (probably) on max hydro and max HID lights and has very little to do with reality and an average home cultivator using (usually) a cheap LED light and growing in a cupboard/tent. Hope this helps,............ Organoman.

I checked the strain, it says 8-9 from seed to harvest indeed, but that's bullshits, 8-9 weeks from flowering to harvest maybe according to your pictures... So my opinion is you should wait until the start of week 10-11 to flush and then harvest around week 12,you'll need a microscope at least x60 zoom if toy want to see the trichomes, it's not necessary but it's helpful

Indications I use to start flush is when mass trichromes are just starting to get cloudy. For me it's been around week 10 or 11 on autos. Then 2 to 3 weeks just ph water. 48 hours darkness prior to cutting. Exact cut time i determine as fade goes. Hope this helps and good luck. You look like you have some time to feed still. Budding strong from picture

Flush now and harvest at week 11