Posted: 04/09/2016 at 12:58
The most common way to grow grape vines is the rod and spur method. With this method there is one main stem which is permanent and the side shoots which grow from it each year produce the fruit. All of the side shoots are cut back hard each winter when the vine is dormant and I do mine in November or over the Christmas holiday period if I forget to do it earler. Starting where the side shoots come from the main stem (which will probably be quite old and gnarled), count two buds along each side shoot and cut it just beyond the 2nd bud. You will and up with just the main stem with very short side shoots. It is vital to do this before growth starts in the spring otherwise the vine will bleed from the cuts.
Vines can be very vigorous and the side shoots on mine will grow 6ft+ in a season if I let them! To control growth and produce larger fruit, cut the shoots back to two or three leaves past the forming bunch of grapes which will appear in late spring or early summer. Only let the vine produce one bunch from each side shoot and snip off and others. Further pruning may be required as more shoots are produced from the joints of the remaining leaves - you can just pinch those shoots out leaving one new leaf on each.
There are other pruning methods depending on how the vine has been grown, the Guyot system being the other main one.