I live in New York. For us apple harvest goes from late August to October. We often go on apple picking trips to the orchards. When the apples turn red or rosy, you will know intuitively when it's ready.

Kay is about ready now, or at least ours is. Easy enough to tell, gently lift a fruit up and if it comes away in your hand it is ready. Katy do not keep so you need to eat them, or juice them, or purée and freeze for winter use.

As for the unknown, if there are enough fruit, you could do as we do here for oranges: pick and try one, and maybe try another 2 weeks to a month later, if too green.

Don't forget to make apple-cranberry pie. The two taste great together.

Yea - if only we could get fresh cranberries here any time other than Christmas, Bathgate, which we can't. I buy tons of 'em in December and freeze... but its not the same as fresh. Cranberry and apple sauce is fantastic with pork...

Maybe the 'raggedy old one' is a Bramley (cooking) apple?

There he is again! uggh!

Who?

I was always told to cut one up and check the pips. If they're brown the apples are ready to come off. ( but I'm an amateur compared to these other guys.)

...and if they aren't brown, jolly well put the apple back on the tree to ripen properly!

My Katys aren't ready yet.