[AlaninCarlisle]

A couple of years ago I planted a black grapevine (Hamburg from memory) in the polytunnel and tended it lovingly. It grew about six bunches last year which were discarded in accordance with best advice. This year it developed over 50 bunches which I trimmed back to about thirty and eagerly watched them turn colour and swell. I even bought one of those dummy wasp-nests to deter the little horrors and it worked well. I picked the first few bunches this last weekend. What a total disappointment. Fairly tasteless and every one with quite a large pip. Not just me but my small grandchildren dislike them too

Is this the best I can expect in these cool northern climes?

[Goneterseed]

I have something similar in one of my greenhouses which I inherited from the previous tennant. It's too deeprooted to digout and I've hit it with glyphosate twice but it still keeps coming back.

[AlaninCarlisle]

Before I dig it up, I'll give the grapes a few more days to see if they get more taste although seem quite ripe already, but so far a bitter disappointment. Anyone else growing grapes so far north?

[snowdrops]

You could make grape jelly

[AlaninCarlisle]

The whole purpose of growing them was as dessert grapes, mainly for my young grandchildren

[Ivor Backache]

I am on the N Wales coast and have grown a Black Hamburg for 3 years and this is the best crop so far but nowhere near 50 bunches. It is rooted in a large pot with the vine in a cold frame facing SW. (gets afternoon and evening sun)
Some are black others are still green and in my view nowhere ready for eating. Have tasted two and found them tasty. (Much better than the tasteless seedless grapes from the supermarket)
By the way never give children whole grapes, because they can choke on them. Always cut them in halve which will solve the seed issue.
We have not had a good summer for fruit. My outdoor toms are just turning yellow. Cherries were rubbish (again)
Apples and plums Ok.
Feed your grapes and cut back the excess foliage. Mine still need another 2-3 weeks.

[AlaninCarlisle]

If I'm understanding you correctly, your vine is mainly outdoor but with roots in a cold frame. Mine is totally contained within a large polytunnel with vine trained along wires close to roof. Daytime temperature gets up to 40C so this might explain why it's a couple of weeks ahead of yours. What I find so disappointing is the lack of sweetness. Maybe, despite the appearance of maturity, they need another week or so

[Hampshire Hog]

Sorry to hear your grapes aren't fit to eat. Given that you are at least getting a crop could you consider turning them into wine? We are knee deep in vineyards here in Hampshire these days so that would be my first thought for inedible grapes.

Cheers HH

[snowdrops]

Victorian gardeners used to pick the bunches with a handle left on & insert this in to water & they would keep for quite a while without Spoiling, which makes me think that maybe you have got a few weeks more before they spoil, it might be that the sweetness develops later. Have a look on YouTube for Harry Dodson I think it was The Victorian gardener from the tv programme or Heligan

[mumofstig]

Did you trim individual grapes out, so the grapes were well spaced in the bunch? It effects size so could effect taste 

[Ivor Backache]

If I'm understanding you correctly, your vine is mainly outdoor but with roots in a cold frame. Mine is totally contained within a large polytunnel with vine trained along wires close to roof. Daytime temperature gets up to 40C so this might explain why it's a couple of weeks ahead of yours. What I find so disappointing is the lack of sweetness. Maybe, despite the appearance of maturity, they need another week or so

No. The root is outside and the vine is in the cold frame. This is the RHS site for growing grapes. (site and soil preparation)
https://www.rhs.org.uk/advice/profile?PID=287
Nothing wrong with your way but there needs to be more irrigation.

[al78]

Is sweetness related to summer sunshine quantity? In my part of the SE June was terribly dull, with light levels comparable to mid December at times (required headlights on whatever the time of day). What has the summer been like up until now in Cumbria? If it has been dull and unsettled maybe the grapes have been a bit sun starved.

[AlaninCarlisle]

June was a great sunny month, July and August have been average. Other greenhouse and polytunnel crops have been fantastic (tomatoes, cucumbers and sweetcorn in particular). Decided that I did two things wrong: Didn't prune as per recommendations and didn't thin them out enough. I'll give them another week to see if they sweeten up a little before throwing in the towel

[ilan]

I would think that they need a lot more thinning out perhaps down to 10 or so bunches, this should get the size up , for table use each bunch should be thinned out as well and I would think you should wait a few more weeks so they start to rasin concentrating the flavours .