Grapevine Pruning Time and Pruning Standards Explained in Detail

Pruning grapevines is very important, as it can regulate the vine's water and nutrients. It must be pruned in all four seasons, so when should grapevines be pruned? What pruning standards are there?

1. When to prune grapevines

Pruning is generally carried out one month after leaf fall, when the nutrients have already flowed back into place. However, you need to check whether the variety has strong resistance and can overwinter safely, such as Red Globe grape, Crimson Seedless, Golden Finger, White Chicken Heart, and others. All of these need to be buried in soil for cold protection, so the pruning time must be moved earlier or the vines pruned while still in leaf, at the end of November or the beginning of December; after pruning, bury the vines in soil to prevent winter damage. Other varieties can generally be pruned from December to January.

Long ago, because people did not have enough mastery of grape pruning techniques, they generally used winter pruning and neglected pruning in the four seasons. Now the old concept has changed, and new pruning techniques are used, carrying out pruning in all four seasons to solve the problems of light and canopy crowding. Reasonably controlling, saving, using, supplementing and consuming nutrients allows the vine to reach a state of balanced nutrition.

1. Spring pruning. This is the spring bud removal method, removing multiple buds, thin and weak buds, and sprouting buds, which saves nutrients so that all nutrients are supplied to the buds that are kept, commonly known as saving nutrients.

2. Summer pruning. Pinching of fruiting canes and vegetative canes, handling of secondary shoots, removal of tendrils, and then cluster shaping, straightening clusters, thinning clusters, thinning berries, and so on.

3. Autumn pruning. The task in autumn is pinching the second round of secondary shoots, removing crowded branches, thin and weak branches, and branches with a low degree of lignification, regulating branch quantity, letting every branch see light, improving light conditions, and making the canopy well ventilated.

4. Winter pruning. Winter pruning of grapes has the largest pruning amount and removes the most branches. Winter pruning is an effective method for determining the next year's yield.

2. Pruning standards

These are determined by variety characteristics, vine vigour, vine age, trellis type and yield. There are thinning pruning, short-cane pruning, medium-cane pruning, long-cane pruning, extra-long-cane pruning, two-cane renewal and one-cane renewal.

1. Thinning method: this means removing thin and weak branches and useless branches.

2. Short-cane pruning method: this is pruning to 2—3 buds, carried out as stumping pruning for newly planted young vines.

3. Medium-cane pruning method: pruning to 3—5 buds, used for gaps where plants are missing, in order to fill the space and increase the amount of branches and leaves.

4. Long-cane pruning and extra-long-cane pruning, 6—12 buds, are generally used on extension main canes, for example when the main cane of a small trellis cultivation needs to extend up onto the trellis.

5. Two-cane renewal: on the basis of the previous year's pruning, each of two canes is pruned leaving 1—2 buds. However, two-cane renewal needs to be carried out when the main cane has space; otherwise the canopy becomes crowded, ineffective leaves increase, and nutrients are consumed.

6. One-cane renewal: this means cutting off one of the original two canes, keeping one cane, and then cutting the kept cane back short; this is called one-cane renewal.

7. Major renewal and minor renewal: major renewal is cutting off an old cane from the base, keeping one sprouting shoot and training it into a fruiting mother cane. Minor renewal is replacing a weaker cane with a strong one. This keeps the vine forever young and prolongs the fruiting years.

When pruning grapevines, take care that the cut surface is smooth, and be sure to protect the wounds.