How to prune a grape vine?
Whether you are growing your grape vines in a row or over a trellis, your grape vines must be pruned each year. Learning how to prune your grape vine is the first step inreaping a bountiful supply of grapes. Grape vines need a heavy pruning that often scares gardeners as they have to remove 90% of the branches!
Is it really necessary to prune the grape vines?
If you would like to collect more than one cluster of grapes, yes! Here is why: the vine will only produce fruit on the new branches of the year. If you let the vine make five meters of branches every year, after 3 years your vine will have to feed 15 meters of branches to reach the branch's extremity where the fruit are! The vine will have little energy left when it comes to the end of the branch, hence the fruit yield will be low. Pruning your vine is essential, as it limits the amount of branches not producing fruit.
When to prune a grape vine?
Some people prune grape vines in spring, but this has a big drawback: the sap will be flowing and the vine will have difficulty repairing its wound. The ideal time to prune grape vines is in late fall or early winter. The latest it can be done is before the first snow.
What tools are needed for grape vine pruning?
Sharp pruning shears are essential for pruning. Flagging tape could be useful to help visualize the cuttings that have to be made.
And now, how to prune the vines?
The technique presented below is for northern climate. If you are growing your vines on a high trellis, use the same technique, but choose your branches higher on the main stem.
Choose the main stem : it is the strongest stem that comes out of the ground. Then cut all the other stems coming out of the ground.
On the main stem, you will have to choose 4 branches. Choose the two strongest branches from both the left and right sides. If supporting your vines with two parallel wires (like shown in the image below) choose your branches so that each of them will easily hang on the wire. Using flagging tape is a great help in identifying the branches to keep. It will also help you to avoid cutting the good branches.
Cut all the branches, except for the 4 chosen, to 1cm from the main stem.
Finally, cut each of the 4 branches between the second and third buds.
(Click on the image to enlarge it.)
Is there any special technique to use when cutting a branch?
When pruning in fall, the wood of the vine dries a little during winter. As a precaution, we always cut the branches 1cm from the main stem. That way, if the wood dries, only the 1cm part left will dry. The aim is ensuring the main stem be intact in spring.
Do the grape vines need any protection for winter?
Althought varieties such as Valiant and Hogan are extremely hardy to cold temperatures, ideally, lay all grape vines on the ground for winter. That way, the snow will cover them and insulate them from the very cold nights of winter. In spring, you simply hang the stem back on its support.
If growing your vines on a high trellis, you will be unable to lay it on the ground for winter. In that case, simply choose a vine hardy to your area.
Pruning grape vines is as simple as this! Do not be afraid to hurt your vine by pruning it. Furthermore, pruning helps the plant to gather more energy and thrive within its environment.
Watching the 3 minute video below demonstrates the technique explained above.
Enjoy pruning !