First sign of flower?

Most folks count from flip date. It’s much less subjective.. I’d recommend that

Yes, when you flip to a 12/12 flower light cycle. That is day one of flower. If it says 9 weeks strain let it go 10 weeks and start to scope on day 65 all cloudy to 20% amber and cut her down. In the end the plant is the boss. All breeder info is also subject to your environmentals and style of growing. Cheat code: You can use a forcing agent in the end winter frost or ripen to be sure.

We call that pre flower. No need to start counting til you switch to 12/12. Also purple stems usually means magnesium defc. Dont switch a plant to flower if its in need of Mag. Now not all purple stems mean Mag defc...but damm bro those are some purp stems!! Add some cal mag or just Mag pref if u got it before u switch ok.

Yep pre flower just indication of sex and that there mature enough to flower and clone

@No_Coast_Genetics Hi mate you are sort of correct what they are showing you is that they are now sexually mature and will flower as soon as you change the dark period to 12 hours of uninterupted darkness A lot of us growers refer to them as "preflowers" Good luck mate