When does flowering actually begin?

I realize you have to go by looks and trichs to know when to harvest. But I have a slight dilemma. I'm at my cabin six hours away from my house and I have a couple plants about ready and one Sativa(Western Winds) that might need a couple more weeks. The problem is that to come back would cost the time to drive and money to drive in two weeks and I don't really know how much it would improve- It's not a big plant.

Western Winds is supposed to be a 70-75 day plant. I waited til I was sure it was a girl and saw quite a few hairs then backed up a few days and called that the start. By that I'm at day 60 now. But when people grow indoors don't they start counting as soon as they go to 12/12, not when they see hairs? If so, I'm wondering if I'm actually technically further along than 60 days right now. It would be great to be able to hold off but to spend $80 on gas and drive 12 hours may not be worth it.

Right now the plant is sticky, green smelling, has "ok" trich coverage, an occasional amber though mostly cloudy and cloudy trichs and a few clear under a scope.

Any opinions would be appreciated.

PS- I posted this in Outdoor Grow section also because I'm looking for opinions before I head home tomorrow night. Thanks all.

Well, depending completely on the strain-dependant maturity time, once you start to see white hairs, the growth spurt that we call Da Stretch is already mostly done. And Da Stretch starts after the plant is induced.

From my experience, a 70 day strain will start to show white hairs around Day 18 of 12/12. That should help your planning.

HTH