Well above average temperatures are being predicted for the later part of this week. This will tend to hasten bud opening in all plants including grapes.
Pruning grapes involves a lot of untangling, tugging and pulling to get the pruned canes out of the way. All of that pulling on the canes can scrape off the buds you want to keep. Right now the buds on our grape vines are still hard and fully dormant and and as such can handle that kind of treatment.
Later this week the high temperatures will stimulate the buds out of dormancy and they will begin to swell and become very fragile. This will be an unwanted complication to your grapevine pruning. Many of the buds that you intend to keep can be easily broken off. The solution is to prune right now, before the buds swell.
I’m guessing probably 90% of the volume of a grape vine is cut off during pruning. Even though the grapevines shown in the photos are being trained for a decorative use rather than maximum grape production, you can still compare the two photos to get an idea of how much was pruned from the vines.
Typically, the “arms” growing off of the main trunk are the only ones left and contain the buds that will grow into this year’s canes. It is from this growth that the grapes will be produced.
There’s plenty of daylight after work this week to get this job done. Plus you’ll have it all taken care of before Michigan State’s basketball game on Saturday and you won’t have to worry about it until next year!