Success problem?

[Eoghan]

This year I took the pruning shears to the vive and really hacked it back. Result - lots of fruit developing - reckon over 40 clusters. Will I need to thin them out last year I got one small 4oz cluster with most of the growth going into shoots. Can provide pics if that helps, it is about 20' long along one side of the polytunnel.

[ameno]

You should thin grapes to one bunch on every shoot.
Depending on the variety, it can be beneficial to thin the individual grapes within each bunch, too, removing every other fruit, as it will give you bigger fruit and reduce chances of fungal problems. It's fiddly and time consuming, though.

[starloc]

I dont think its necessary to thin them , Nobody here in Bulgaria seems to thin the fruit or thin individual grapes, i dont either and get loads of them, the important bit seems to be chopping the last years growth back to get new growth as they fruit on new growth grown from last years buds

[ameno]

I dont think its necessary to thin them , Nobody here in Bulgaria seems to thin the fruit or thin individual grapes, i dont either and get loads of them, the important bit seems to be chopping the last years growth back to get new growth as they fruit on new growth grown from last years buds

It's a lot warmer in Bulgaria in the summer than it is here, though. Depending on the variety and the amount of sun they get, a vine can struggle to ripen all of them in this country is they are not thinned.
Also, although wine grapes usually are not thinned (because small grapes with a high skin-to-flesh ratio is actually preferable), eating grapes usually are (whole bunches, at least. Commercial growers don't thin individual fruit, as that's too labour-intensive).

[starloc]

I dont think its necessary to thin them , Nobody here in Bulgaria seems to thin the fruit or thin individual grapes, i dont either and get loads of them, the important bit seems to be chopping the last years growth back to get new growth as they fruit on new growth grown from last years buds

I also grew marachial foch and lakemont in the UK in Liverpool, the foch was very small but the Lakemont was normal size without thinning down, not that they might not have been a bit bigger if thinned but there was no reason, and they ripened fine evenb though it was cold

[Eoghan]

The attached photo shows my vine. There are no leading shoots after pruning and I can see definite development and swelling of the fruit.

[Snoop Puss]

Looking good there, Eoghan. Beautiful green leaves.

[Eoghan]

Yes but there are no leading shoots extending to form a canopy

I used to measure it's health by the number of additional leaves. Now I am endeavouring to thwart that, vine pruning must be a fulltime job in France! You cannot let up or all the growth will go into shoots not fruits

[ameno]

Yes but there are no leading shoots extending to form a canopy

I used to measure it's health by the number of additional leaves. Now I am endeavouring to thwart that, vine pruning must be a fulltime job in France! You cannot let up or all the growth will go into shoots not fruits

All the growth will go to the shoots, anyway. The idea that summer pruning redirects the plants energies into the fruit is a myth. Just as much energy goes into growing shoots whether you cut them or not.
The reason for summer pruning is to allow more light and air flow to the developing fruit, and to simply keep the vine at a manageable size and stop it getting completely out of control.

[Eoghan]

You saying I should let some shoots grow? The vine had four grape clusters on a 20 foot spread and produced one 4oz grape cluster. Loads of greenery but one tiny grape cluster.

[ameno]

You saying I should let some shoots grow? The vine had four grape clusters on a 20 foot spread and produced one 4oz grape cluster. Loads of greenery but one tiny grape cluster.

No, I'm just saying that "redirecting growth" is not the reason for summer pruning.
If you previously had low numbers of flowers being produced then that's usually down to inadequate winter pruning, not summer.

Although in a climate where the sun is weaker, like yours, you should indeed actually go easy on the summer pruning, removing maybe only half as much as usually recommended. This is because the leaves are needed to make sugars to ripen the fruit, and in places where the sun is not as strong more leaves are needed to make the same amount of sugar.