How to prune a grape vine?
November 23, 2012
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 to a heavy grape production. 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 be producing 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 not have much energy left when it comes to the end of the branch, hence the fruit yield will be very low. Pruning your vine is essential, because it limits the amount of useless branches to feed. (read: 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?
A well sharpened pruning shear is essential for pruning. Some flagging tape could be helpful to help visualize the cuttings that have to be made.
And now, how to prune the vines?
The technique presented below is a technique for a northern climate. If you are growing your vines on a high trellis, use the same technique, but chose your branches higher on the main stem.
Chose 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 chose 4 branches. You will have to chose two from the left side and two from the right side, the strongest from each side. If you are supporting your vines with two parallel wires (like shown in the image below) choose your branches so that each of them will easily be hanged on the wire. To help yourself visualize before you cut the branches to eliminate, attach a piece of flagging tape to the 4 branches you want to keep. It will also help you to not make a mistake and cut the good branches!
Just cut all the branches, except for the 4 chosen, to 1 cm from the main stem.
Finally you will need to cut each of the 4 branches between the second and the third bud.
(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 1 cm from the stem. That way, if the wood dries, only the 1 cm part left will dry instead of the main stem. The aim of all this is that the main stem be intact in spring.
Do the grape vines need any protection for winter?
Althought some varieties are extremely hardy to cold temperatures (Valiant, Hogan) it is always preferable to lay them 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 you are growing you vine on a high trellis, you will not be able to make it to lay down for winter. In that case, simply make sure you choose a vine hardy to your area.
Pruning grape vines is not more complicated than this! Do not be afraid to hurt your vine by pruning it. Opposingly, pruning helps the plant to not tire itself for no reason!
You have the opportunity to watch a 3 minute video below that demonstrates the technique explained above.
Enjoy pruning !