Wondering how to prune grape vines on a trellis? Pruning grapes in fall can help maximize harvests and overwinter the plants successfully.11
In the Southern Colorado River Plateau region of Arizona, fruit production is iffy at best. Peaches produce about once every ten years or so, and apples average every fourth year. One fruit that is dang-near 100% reliable in this area, though, is grapes. And one particularly amazing variety here is the Himrod grape. But even though grapes will produce nearly every year with very little variance, the key to good quantities of grapes each year often comes down to pruning.
While it is appropriate to prune your grapes, and any other fruiting bush, tree, or vine any time there is damage, the best time to heavily prune grapes in our area is very early spring, around the first part of March.
In fall, your grape vines will look a bit like this (below), provided they had good water and grew well.

If you have relatively mild winters, it doesn’t hurt to do some rough pruning at this stage. However, the best time to prune here is springtime, after winter has killed back a lot of the sprouts from last year, leaving you being very sure about what is alive and what is dead. When I say “rough pruning,” I mean taking off large dangling branches that grow out of the main stalk, like here:

These need to come off, as grapes need good airflow and good light penetration to all the leaves. Branches like this, coming right out of the main stem, can tangle, serve as home for critters, make your grape vines look raggedy, and aren’t usually all that productive. I trim them very close to the main trunk.
In spring, your goal is to just have a short piece of last year’s wood from each of the side-branches. Most vineyards and home gardeners want to use the “Double-Arm Kniffen” style of growing grapes. In this system, the grape vine is trimmed to one main stem the first year. If there are arms coming off the stem, they are all trimmed away except possible one-four branches, if they are in the right point to grow arms out to the side like this:
Because grapes grow from new shoots coming from old wood, these four branches are the really productive wood, but only if you trim all the stragglers and keep the main trunk trimmed to only these four side branches.

The picture below shows how short I cut the shoots from last year. Each one of those nodes has the potential to make a fruiting sprout, so I limit the nodes to 2 to 3.

Double-arm Kniffin system
After pruning all branches coming off the main trunk, and trimming down all the old wood on the four arms, all that’s left is to cut off anything that’s obviously dead from the cold.
You can usually tell pretty easily which wood is dead and which wood is alive. Living wood will have a rich, brown color, and dead wood will be brittle and gray. The wood that is completely gray will not grow new shoots and thus will not be productive ever again, so it should come off as close to the arm of the vine as you can get. Sometimes these side shoots have been productive for a couple years and you’ll need large pruners or even a saw to cut them once they die completely.
After all this pruning, you’ll have a grape vine that looks similar to this. All the side branches should be completely free of old leaf litter and long, dangly vines.

Grapes pruned in this manner will be easier to take care of, harbor fewer pests, and be more productive for years to come.
More grape-growing tips:
Old Fashioned Grape Juice Recipe
How to Build a Grape Trellis Backyard System
Regina Hitchock is a high school biology teacher in St. Johns, Arizona, where she co-founded the Gardeners with Altitude organic garden club and brings gardening, aquaponics, aeroponics, hydroponics, and seed starting into her classrooms. She serves as Secretary for White Mountain Community Cooperative to promote food- and economically secure self-sufficiency in Arizona.
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