need a little advice...

so i started a little later than most for outdoors, i planted them in early may, and now my five outdoor plants are about 3 feet high, but haven't started to sex. i just added some 16-16-16 fertilizer today to them, and i was curious when the days are going to get short enough so the sexes will start to show... i live on the west coast, if that is any help. thanks.

 

It depends on the strain. They'll start flowering between now and mid-Aug.
I have my legal limit of 12 plants and one just started to indicate flowering. The other 11 (different strains) are still in full veg.
When flowering begins plants put on a "growth spurt". They start getting tall FAST. That's the first thing you notice. Then a few days later the males will start growing balls. At the beginning of week 3 of flowering the females start to grow buds.
Continue to use veg nutes until week 3 then switch to flowering nutes.