I don't think this years weather is the problem as it's been a bumper harvest for grapes this year, mine has done very well.

You mentioned that you have lots of grapes, albeit small ones, so I think the problem could be that you didn't prune it right. Correct pruning is probably the most important thing to get right if you want to grow nice grapes and the pruning should be done in the winter when the vine is dormant.

There are lots of web sites with information about how to prune your vine and it's sometimes complicated to get your head around all the jargon used.

It helps if you thin a lot of the grapes out in the early stages to encourage growth of the others that are left. I can't bring myself to do this and I've found that if I take some time pruning it in correctly in December I'm rewarded with luscious grapes every time.

Myron, many thanks for your advice. I now have pruning tips from the web. I'll get the secateurs out in December.
I've also been told that liming the soil might help. Any comments on that from anyone?
james90d.

I wouldn't use lime, grape vines will grow in a relatively poor soil. You could add a balanced NPK fertilizer or dig in some slow release fertilizer such as Growmore in April just before the growing season, but I never feed mine. Is your vine outside or in a greenhouse.

Hello again and thanks for your latest comment.
My vine is outside , the soil is heavy Thames valley clay, and this morning I found a near neighbour with the same problem. Any other suggestions I will pass on to him.

Grapes vines aren't too fussy about the type of soil and will tolerate most soils, but it needs to be free draining. If you have heavy clay soil, then I would add something to break it up.

Maybe you mentioned liming because of the clay soil which would make sense? I wouldn't use lime unless your soil is too acid as this will upset the pH balance. The ideal pH for grapes is 5 -7 which is slightly acid. Gypsum is another improver to add to a clay soil, but I personally I would dig in lots of organic matter and you could also add some grit.

Apart from holding water, clay soil will take longer to warm up in the summer, so this could be detrimental to grape growth as the roots prefer warm soil. For this reason most grape vines for commercial use are grown on soil with lots of stones on the surface. The stones will heat up during the day and release this heat into the soil at night.

Many thanks for the latest advice. I will certainly be guided by that, and look forward to a better outcome next year. (if I've learned anything from gardening, it's that patience is needed.)

You're welcome :o)