Four Arm Kniffin System for Growing Grapes
David Handley: I'm David Handley, vegetableand small fruit specialist with the University of Maine Cooperative Extension. Today we'regoing to be talking about a simple system for pruning hardy grapes here in Maine. The pruning system I like to use is very simple.It keeps the plant open, so it gets light in the summer time, but it also protects theplant a little bit in the winter. This system works best with concord type or labrusca typegrapes, which are the grapes that tend to grow best in Maine. There's really a couple of systems that willwork well for labrusca type grapes. The first
one I want to talk about is the four arm kniffin,and that's what we're going to prune first. The four arm kniffin consists of a perennialtrunk, which goes from the ground right up to a top wire, which is set at about fivefeet. Coming off of this trunk, we will have four arms, or canes, oneyear old growth.Two on the top wire, running each side of the top wire, and two on a lower wire. Thislower wire should be set at about two and a half feet off the ground. Every year, we're going to come in and pruneit so we continue to have a perennial trunk, but only four one yearold trunks to producethe fruit.
Here is our permanent trunk. You can see here,this is a cane from last year. Two yearold cane, this was our fruiting cane last summer,and you can see the difference. Here's this year's cane, that nice chocolate brown colorand smooth bark, and here we go with the older cane, the two yearold cane. The bark is startingto peel, and has more of a gray look to it, so we know that this particular shoot isn'tgoing to fruit again. It's the one yearold shoots that come off it that will fruit. This is going to get pruned out, so that wecan keep our fruiting wood closer to the trunk. We'll just take that back to a good fruitingshoot, and we'll start to cut it out. This
is where it gets fun. We need to wrestle thisout of the trellis, and of course, all these little tendrils have tied it up and aroundmost of the growth that's there. It takes a little bit of cutting, but be careful notto break the fruiting canes that you want to leave behind. Pull it off, and that will open the plantingup so we can see what we have left for good fruiting wood for this year. We've taken offthe four fruiting canes that we left last year, and you can see pretty much all that'sleft, at this point, is the green shoots from last year, that will provide us with goodfruit for this year.
Now we need to choose which four we want toput up. We're going to have four canes. One, two, three, four. Two for the lower wire,two for the upper wire, each heading off in different directions. What I want to look for in this case is canethat's got this nice chocolate brown color, and is about 38 of an inch in diameter. Aboutthe width of your little finger. If it's thinner than that, if it's very weak, it won't producegood fruit. Thin stuff like this, less than 38 of an inch in diameter, we'll just cutthat right out. Here we've got one that's going to go in thisdirection, that looks very nice. I'm going
to count, remember we want about 10 buds onit, so we'll count our buds. One, two, three, four, five, six, seven, eight, nine, 10. ThenI just cut out beyond that, because the weaker stuff at the very end isn't going to producevery good fruit. I have my four arms, but you can see I stillhave some leftover canes. What I'm going to use these for are what we call quot;renewal spurs.quot;I'm going to cut these back so that they just have one or two buds on them. What I'm goingto use these buds for, the green shoots that will emerge from these buds and grow out,will be the canes that I'll be putting on the wire next year for fruiting. We call thesequot;renewal spurs.quot;