[AlaninCarlisle]

Two years ago I planted a Regent grape in my polytunnel. Last year it created two vines each about ten feet long along the roof of the tunnel, both of which bore one bunch of grapes each. This year, it looks as if both branches are going to produce at least ten bunches each. Should I let them develop or thin them out to a lower number on each branch/vine?

[Trikidiki]

What do you want to do with the grapes and how much time do you have?

If you want decent eating grapes you want to be able to spend time thinning the grapes in the bunches so you get a smaller number but bigger/sweeter grapes. It is time consuming so decide how many bunches you can cope with.

If you are making wine I would let as many grow as the vine looks like it will support.

I have an outdoor "Hampton Court" vine. It has two vines about ten feet long. I usually allow a bunch every eight inches. I did try thinning the grapes one year but as they are seeded (which I hate) I don't bother now and just feed them to the chickens.

I planted a Lakemont seedless grape in a greenhouse last year, it is just producing a few bunches which I will try to thin to get some decent grapes. I grafted a couple scions of it onto the "Hampton Court" vine last summer but the muppet that my wife employed to cut the grass decided to prune the vine and cut them off.

[AlaninCarlisle]

Thanks, I think that this year I'll just let them develop as many grapes as they want and see how edible they are. Certainly the  two bunches produced last year were quite edible. Both I and the wasps enjoyed them