The seed bank your strain is from suggests 5-7 weeks of flowering or 9-10 weeks after sprouting.
You ladies look good, they have a few amber trichomes.
I'm seeing this 5 days later, I would say if you haven't go ahead and start flushing.
Those 1-2 weeks of flushing is NECESSARY if you've been using nutrients.
Flushing isn't to save the cost of Nutes for the last few weeks.
It's for CLEANING the roots of all that build of Nutrients, that way giving a cleaner, better and more natural taste to your buds.
If you don't flush correctly you can end up with nutrients still in your plants and you don't want that.
Flushing too early or too late can be bad.
Too early can damage your yield and quality.
Too late can decrease THC levels and increase CBN.. as trichomes will keep turning amber day by day in those 1-2 weeks..
Which will give a couch lock type of high if theres a lot of CBN.
Hope this helped.
Good luck! 👍