When should I start to flush these girls?

They have been flowering for about six week, I'm pretty sure they are Northern Lights but bought the seeds over a year ago before i discovered Attitude Seedbank and they weren't marked.

Thank you for all of your help in advance and for your previous help
zz

Elevendy weeks or so

marijuanaganja said:

Elevendy weeks or so

Click to expand...

This calls for a second opinion

They are in sn ebb snd flow hydro set up btw

flush 1 week before cut down,
that's what i do

you got some sativas there, and they go for months before flowering, id be more worried about the height.

From what i can tell from the pics you have a little while, still have lots of green leaves and its making fresh pistails,right?

Yeah looks like another 3-4 weeks minimum. I can't tell for sure but i see all white pistils(hairs)...

yeah, they are getting too tall. I need to start tying them down this week.
Thanks for the advice, I'll start the flush at the end of the month.