Hi Isoh,
What kind of Blueberries?Some flavor is better if left on longer and it could depend on variety.Where is your location? Brady

I think there's some rule of thumb for how many days/weeks after turning blue. Don't know what it is though.

Of course, the surest way is to regularly sample. You'll become an expert.

This variety is Duke. I live in Northern Ohio, zone 5.

EAT ONE

I have some young Duke's.From what I've read they are fairly mild flavored but are suppose to be the most popular planted variety in the area where I live,the Pacific Northwest. Brady

It usually takes a few days after they turn blue to fully expand and ripen. And you can't expect to harvest in one session as blueberries ripen in succession.

One way to tell if they are ripe is how easily they fall off. Most varieties will allow ripe blueberries to come off by a slight tickle of the berry. If you have to pull or twist them off, they aren't ready, even if they are blue.

Don't know if this is true, but based on my (first) harvest this year, it seems to be. I read somewhere that the berries are ripe after they turn from light blue to dark blue.

In other words look for a darker shade of blue and pick those berries. The light blue ones will soon turn dark blue, and the "white" ones will soon turn light blue.

Some varieties though take on a deeper blue when fully ripe.Usually the taste will be better if left on the bush after the last color change.Experience will be your best helper. Brady

I always look under the berry at where the stem attach to see if there is any reddish shade. If no reddish color and easily fall of then I will pick them; if it still has little red shade , them I will let it stay for few days.

BTW, I think calliope's answer hits the target.

Hold the berry and tell it to turn its head and cough...Lol

When the bottom of the berry turns to the same color/shade of blue as the top of the berry. Makes them difficult to pick. :)

Some articles I have read say only pick once a week and 2 times at the most, if it is hot. My question is: If I pick on a Monday and not again until, say Sunday, each day of the week more berries will have changed color so that by Sunday I don't know which ones turned blue on Tuesday, or just turned blue on Saturday. I guess it is a percentage where I will at least get a small amount that are truly ripe and a lot will be the same as if I picked every other day. I guess I was happier when I didn't think about it!!

I wait till half the berries on a given bush are ripe before picking them then pick all that are solid blue. The next picking I wait till half what is left is solid blue and pick and third pick is the last pick. Doing that you will get about 60% that are dead ripe and the remaining berries will be not quite to not very ripe. I rather like eating the not so ripe ones and dead ripe together as it gives a nice balance.

If you pick every day or two you will get more berries and the birds less but there is no quality.

I consider mine ripe when they are sweetest. I leave them on as long as possible. They seem to continue swelling and get sweeter the longer they are left on. I'm willing to sacrifice firmness for sweetness.

I pick when they are fully blue (no purple) but some turn almost black, others keep a blue frosted look so also feel. If it "gives" a little it's ready, if hard it's not, and if it squishes you waited too long :-) But have to get them before the birds do.

Keep in mind, each blueberry variety has it's own taste/sweetness and it can change somewhat each year, depending on the heat/moisture.