Growing Grapes Article 5 - Grapevine Pruning
In order for your grape garden and grapevines to obtain the highest yields of maximum quality grapes and allow a decent vegetative growth for the following year's growth, the grapevines must be pruned. You see before pruning, a grapevine may have anywhere from 200 to 300 capable fruit producing buds yet, if left unpruned, the amount of grape clusters become boundless. This causes the unpruned grapevine the inability to ripen the crops nor sustain enough vegetative growth. Therefore, it is important that we verse ourselves a little bit with grapevine pruning.
The best time of the year to beging grapevine pruning is in the early spring or late winter. You will have to estimate the amount of the previous season's growth in order to determine the 'vine vigor', which is what dictate the range of pruning. The act of pruning grapevines based on plant vigor is known by the term 'balanced pruning.'
Now on to the procedures.
First off, you will have to estimate the number of 1 year old wood in pounds and hold the applicable amount of fruiting canes per vine. A grapevine which is trained to a four cane Kniffin system will obviously require four fruiting canes while six fruiting canes will be required when the grapevines are trained using the six cane Kniffin system. (More about Kniffin system in Article 4) Make sure to leave an equal amount of renewal spurs, the ones you pruned back to only 1 or 2 buds, because the buds on these spurs provide shoots and will the sole producers of your grape garden canes next season.
Now, completely remove all the other canes using the weight of the canes, determine the amount of buds to leave on your grapevine. Use the '30 plus 10' formula, also known as the 'balanced pruning formula' which works like this: Leave 30 buds for the first pound of canes removed while leaving an additional 10 buds for each extra pound. Don't forget to include the fruiting cane buds on the renewal spurs when determining the amount of buds retained on your grapevine.
Here is a deeper look at the Balanced Pruning Method:
You are given a grapevine which had 2lbs of canes removed at dormant pruning. Using the 30 plus 10 rule, you would leave 30 buds for the 1st pound of canes plus an extra 10 buds for the 2nd pound. This would give you a total amount of 40 buds. Now, using the four cane Kniffin system, each of the 4 fruiting canes would have about 8 to 9 buds. The 4 renewal spur would have 1 or 2 buds each.
A similar example using a grapevine with 3 pounds removed at dormant pruning would go like this. Leave 30 buds for the 1st pound, 10 for the second, and yet another 10 for the remaining 3rd pound, equalling 50 in total.
Pruning grapevines is highly important during the first growing season and all throughout your grape growing experiences. Although the above guidelines should help you with grapevine pruning, I would advise you to check out some of the advanced tips and diagrams found in this
grape growing website, here.