It's time to Prune Grapevines
Grapevines should be pruned during winter while they are dormant, preferably in December or very early in the New Year at the latest to avoid bleeding of stems as the sap starts to rise in early spring. Further light pruning can be carried out in summer.
Pruning can seem quite daunting but just a few simple steps will keep your plants in good health and hopefully producing some delicious fruit. The easy method described here is based on one or two permanent stems which carry the fruiting side shoots.
In winter shorten the new growth by half and cut back some side shoots to one bud from the leading stem and others to two buds, these will form the fruiting spurs.
Cut back developing main stems by half their new growth and established stems to a single new bud.
Later in the summer you can shorten non-flowering laterals to four or five leaves and any side shoots growing from these to one leaf.
Laterals carrying flowers should be cut back to two leaves beyond the first truss and remove any extra trusses.
Cut back the side branches to one or two plump buds from the main stem.