when will they really be ripe?

I don't know They are a 6 weeks old. I still have fruits from 1 year ago not quite ripe yet. The orange fruit was quite bitter.

This fruit i 13 months old now

My rinds were slightly sweet with the flesh a little sour.

Is there much juice in a fukushu? Like enough to flavor a drink? Ive never had one of those.

Yes, but mine are about an inch in diameter and it would take a couple fruits. The de-juiced peals should be tasty.

Awesome to see that you finally got some fruit, Steve! I am curious that they are so small and a little bitter though. Mine typically run between 2 and 3 inches, (I got one last year that was 4), and are really sweet and really juicy. (I like to slice them thin and eat them or add them fresh to dishes.) I wonder if it's a climate thing or an age thing.

Calamondindave, not sure about Steve's, but I sometimes grind a few of mine into smoothies. They're really good with banana, passion fruit, and a little sugar.

Smothies, Good idea My 2 Fukushu kumquats are seed grow and were very different growing from the start. This one has sour fruits. The other one I gave to a friend who gave it back, too big. He liked his fruits I do not have any fruits from his tree yet. Rootstock may make a difference. His fruits were the same size. My Meiwa kumquats are less than an inch when ripe. It might be climate. They too are on their own root and produce sweet fruit throughout when totally ripe. I pick mine when there is some green mixed in for some twang in the taste.

They are fabulous in a gin and tonic.