Ready for Spring
February 16, 2011 by Mike Monnin, CSW (Certified Specialist of Wine) Corporate Wine Educator, Cincinnati
As I sit here in the dead of winter, snow and ice all around, I can't help thinking forward to my favorite time of year-SPRING! Since my life is pretty wine-centric, I also think about grapevines, dormant now, and wonder what 2011 will bring in the way of a wine crop. In the southern hemisphere harvest is only a few months away. In the north, the winter pruning should be finished, and the vines resting until bud break in another month or 6 weeks.
As for pruning the grapevines, it is not question of IF you should prune the grape vines or not; it is a question of WHEN you will prune the grape vines. As we all know (so I hope); pruning is one of the most important manipulations a grape grower needs to do. Without pruning the grape vines the correct way, you simply cannot expect them to produce healthy, good-looking grapes; or even any grapes at all!
One of the main reasons so many grape growers fail to have a proper grape crop is their inability to prune the grape vines the correct way. Now, a common question is: "What will happen if the grapevines are NOT pruned?"
Without pruning the grape vine, a huge amount of buds will sprout in spring - having up to 300 buds on a single grape vine is not impossible. As you can imagine, for a grape vine to produce enough energy or carbohydrates to feed all of these buds, it will put the grape vine under a huge amount of stress. This brings us to what I want to share with you in this article.
A grape vine under stress is much more susceptible to cold damage than a well structured and previously pruned grape vine. The grape vine will come out of dormancy once the average temperature outside rise to about 50 to 53 ºF, or if you prune the grape vine, or if you use a "rest-breaking" agent like Dormex (a chemical used by commercial grape growers to force the grape vine out of dormancy).
In the northern hemisphere, and where spring frost is a problem, cold damage after pruning the grape vine or after the first signs of new shoot development (bud break) can ruin the upcoming grape crop and therefore you need to protect these buds at all cost.
One of the best ways to protect your grape vines from spring frost is the timing of when you will prune your grape vines and how you will prune your grape vines.
Pruning too early will result in the grape vines coming out of dormancy earlier, and therefore increasing the chances of spring frost damage. On the other hand, as mentioned earlier, you don't want the grape vine to go into bud break with too many buds! Correct pruning methods, and the timing of them, is an art handed down through generations of grape growers, from father to son, from teacher to student. This subject can fill books with information, but for here, let's assume the pruning has been done properly. Then, once spring is on hand, buds on the fruiting canes will start to swell and drop their scale leaves from the end of the cane (bud break will start from the tip of the canes). After bud break is flowering, and the season starts again.