A few clusters on one of my St Croix Grape Vines are more than twice the size of the other grape clusters. I want to try and grow new vines from these grapes and would like to know how to prepare the seeds and how and when to sow them. An e-mail would be greatly appreciated claude_leohudon@hotmail.com I meant the grapes on these clusters are twice the size of the other grapes. Sorry Lee
That is probably not a heritable trait. Instead try to prune away the smaller fruited vines and leave those that produce large fruit. If they continue to produce larger fruit next season then propagate those vines via cuttings or layering.
You could try doing cuttings from the vine that is producing abnormally large grape clusters, but I agree, the seed is unlikely to breed true. Though once you have some cuttings you could then attempt to cross breed, but it would be a fairly week genetic stock, basically trying to breed clones. http://www.eccevines.com/growing-grapes-from-cuttings.html has instructions on doing cuttings for vine propagation.
