There are a handful of grapevines growing out at the Urban Farm and it’s pruning season! Some of them they let ramble, while others they focus on maintaining for good quality fruit. We went to work on the maintained vines and I learned a lot.
Last year I attempted to prune my two grape vines and wasn’t really sure I did it right. With a gardening book in hand and raindrops plunking down, I tried to visual how the illustration in the book related to the gangely vines in front of me. With Tom by my side this year, I learned a lot more about how to prune grapes on the farm.
Tom uses the spur method, rather than the cane method. More specifically, he uses a four arm Kniffen system of spur pruning. It is fairly simple when explained properly (which I hope I can do).
You want the grape vine to have a central “trunk” and four vines coming off of it – two on either side of the trunk. You want to use the strongest, best vines for those four main side branches. You can mark them with a tag in the summer if you realize one branch in particular produced really tasty grapes. Or you can keep using the same four branches every year if they look healthy and perform well. The finished pruning is pictured here.
You cut off any stray shoots coming out of the “trunk”. Marking the four main side branches with colored tape may be a good idea to keep yourself from accidentally snipping off your prized side branches.
You then determine how long you want the grape to reach out. You can cut it way back if you have multiple grapes planted within a few feet of each other, to keep good air circulation and prevent them from becoming too intertwined. You can also let them grow out several feet on either side if you want to cover a fence or something. Be aware that grape experts think the quality can go down though if the side branches get too long, but I think they are talking about ten feet on either side.
We left these side branches about 4′ long on either side of the “trunk”. You then work your way along each of those four side branches and trim down the off-shoots. We can call the off-shoots from these four main side branches “sub shoots” or something. You snip those sub shoots down so just two buds remain on them. Here is a picture of sub-shoots with two buds on them.
You end up doing a LOT of trimming – much more than I thought. You will have the main “trunk” vine, two main side branches on the left and two on the right, and smaller sub-shoots coming off of those side branches that have been trimmed down to just a few inches that hold two buds. You can even decide to fully cut off certain sub-shoots, if they are growing too close to other sub-shoots or look damaged. I am including a sketch to help explain what things should look like.
Grapes can grow significantly over just one season, so these guys will be really full and grow longer branches come summertime. We were leftover with a large pile of grapevines that one could either dip in rooting hormone to try to propagate, or just reuse the bendable vines in a garden project outside.