A grape vine consists of the rod which is the main central stem of the vine, from which spurs occur.
These spurs generally form at intervals of 200-300mm (8”-12”) up the rod, it is from these spurs that the fruiting laterals will develop.
Pruning is dependant upon how the grapes are grown, i.e. cordons, espaliers or fans.
Once the young laterals have started to flower, they should be thinned to one lateral per spur.
Choose the lateral with the strongest flowers and pinch out the shoot two leaves beyond the flower cluster.
If a lateral has not flowered, pinch it out after five sets of leaves.
If any other laterals are produced from the spur, prune these back to one leaf, similarly if side shoots are produced, pinch these back to one leaf also.
Aim for one bunch of grapes per 300mm (12”) of rod, to produce more will only affect size and quality.
Plus the fact over-cropping can affect cropping in subsequent years.
Pinch and tie in laterals on a regular basis during the season.
This system is generally used on vines grown in a Vineyard, and is used to create the annual replacement of fruited wood with new shoots.
The vines are also trained to produce a low trunk from which three replacement shoots will develop from the central arm.
In winter train in two new shoots horizontally, and a third shoot in the centre, these should be cut back to three buds.
In spring the shoots emerging from the two horizontal arms are trained vertically at 150mm (6”) intervals, and tied into a two wire framework.
Pinch out these shoots to two or three leaves above the top wire, remove any side shoots that may form.
Similarly, allow three strong shoots to develop from the central arm, and pinch back any side shoots that may form to one leaf.