Planting Grape Vines - Sour Grapes?

by mr robert howes

Hi,

I have two grape vines one black and one green, 5 years
old facing south in heavy clay soil.I have fruit on the
two vines which i have left on, but the fruit is small
and sour how can i improve the fruit for next season.


Hi Robert,

the quality of the fruit depends on several factors.
First is the variety or type of grape vine that you chose. Some varieties just don't have sweet flavor and if that is the case there is not much you can do about it. Do you still know the name of the varieties?
The other reason for sour grapes could be that the plant simply set too much fruit. The grape vine plant produces the sugar through the photosynthesis process. If there is too much fruit the plant won't be able to produce enough sugar and the grapes reamain sour.
Thinning out the fruit will solve this problem. Just remove about half to a third of the fruits.
Sometimes removing some foliage that shades the grapes can also help.