Grape Vine

On our white grape vine in our greenhouse, the grapes (not yet ripe) are starting shrinking, rotting and going black. This has started in the last 2 weeks, they have been watered twice a day.

 

There is a problem called shanking that grape vines are sometimes prone to, I don't think there is anything you can do for it...i'll see if I can find a link

 

http://www.rhs.org.uk/advice/profiles0802/grape_shanking.asp

there you go