Grapes are among some of the oldest cultivated fruits in the world. Long before people cultivated grapes, the vines grew wild by wrapping their tendrils around the twigs and branches of hardwoods and growing up into the canopies of trees. When people began cultivating grapes, they discovered that the fruit quality improved when the grape vines were pruned.
Archaeologists believe that attempts to grow grapes commercially began along the Black Sea in approximately 6000BC. The ancient Greeks made the first serious efforts at systematically cultivating grapes for wine making. But Greek wines were sour and needed to be watered down and heavily spiced to improve the taste. The Romans improved on Greek winemaking techniques and invented many of the modern practices that vintners use today. The Romans invented the paring knife to make pruning easier.
It is not certain who invented the process of pruning grape vines. The practice stems from the same philosophies of quality over quantity that come from thinning a fruit tree. The idea is that if a grower reduces the number of fruit that a plant must grow, the plant will put more energy into developing each remaining fruit into higher quality. Pruned vines produce fewer grapes, but each grape ripens to the highest quality. Unpruned wild vines typically produce smaller grapes that are sour in flavour.
Grape vines are typically pruned each winter around February after the plants have gone dormant. All of the shoots that grew in the current year are cut back to the first five nodes, which are known as spurs. The grower then weighs the canes and shortens the shoots based on the weight of the canes. This method is known as the 30-10-10 method. In this method, a grower leaves 30 buds on the vine for the first pound of cane removed and another 10 buds for each pound after that. This method ensures that the canes will regrow to the right size and be productive.
In addition to keeping the vine productive, pruning grape vines helps to keep the plant at a manageable size. Managing the size of a grape vine helps the grower be able to better care for it. This care includes keeping it small enough to promote air circulation between the vines and not overtaxing the trellis that it grows on. Properly sized grape vines are also easier to cover with netting to protect them from birds and to harvest.