Comparison Between Different Grape Pruning

Master Gardener Chuck Ingels of the UC Co-op Extension talks about grapes at the Fair Oaks Horticulture Center in Fair Oaks, California near Sacramento. Ed Laivo of Dave Wilson Nursery and here we are the Fair Oaks Horticulture Center and the beautiful grape inventory that they have out here. We’re going to talk to an expert on these grapes out here, Chuck Ingels. Hi, I’m Chuck Ingels with UC Cooperative Extension. I’m a Farm and Horticulture Advisor and we’re here at the Fair Oaks Horticulture Center looking at our vineyard. And this is a vineyard of table grapes only and this is an arbor with a Thompson seedless vine on it. It’s very productive. You can see that the chunk wraps around the post and then comes up here to produce the canes that produce the grapes. What we demonstrate here is cane pruning versus spur pruning so Thompson seedless is always cane pruned. We have another one over on the other side that’s a flame seedless which is spur-pruned. We have about 10 to 15 master gardeners who worked on this project and so there’s a lot to do at this time of year and we are demonstrating shoot thinning and cluster thinning and how to produce table grapes for the best and largest fruit. And these are spur-pruned grapes and so we produces in the winter. We produce spurs. We cut these canes down to two buds and then now the new shoots have grown from the spurs and they’re directed up and over these wires which gets some kind of growing upward but then they come out so they stay away from the fruits here and it doesn’t get too dense. You notice how much space and light there is coming through here. That’s what we’re looking for. And right now, we’re removing shoots where there’s too many of them. We really only want about two shoots coming from each spur so we’re just pulling individual shoots that don’t belong that we don’t want. For instance, here’s one that just we don’t need because there’s already another one. You notice here’s the cluster, there are two clusters on this one and when we come along and do our cluster thinning, we’ll remove one of those clusters and just leave one so that the fruit on that one that are left are bigger. So, it’s like fruit thinning in the orchard. As well, we also we remove the bottom of the cluster so that it becomes around a cluster if you buy them in the store, you’ll notice that instead of being nice and long, they’re rounded because in the field they remove the bottom portion and that also helps the fruit to become larger. So, here’s the vine that has not been thinned yet. Notice how dense it is in the canopy and that reduces the amount of air flow that comes to here so later on the season this gets so dense that if there’s rain or anything you can get a lot of rot. By opening up the canopy by removing shoots and by doing leaf removal which we’ll do a little bit later, then we get better air circulation and it’s actually better fruit quality as well as less disease. And if you come down here, this has been thinned and you can notice a big difference. See how much more open it is and so we only have two shoots coming off each spur which we’ve left. We’ve removed all the other shoots. That’s more open canopy but still high production and large fruit. So, these are cane-pruned vines and you could see the cane that we’ve left which is last year’s growth left along cane because the theory is at the base of the cane you don’t get shoots with fruit although you see fruit right here at the base of the cane so it doesn’t always apply. But that’s the theory is that if you spur pruned this then you would only have shoots that have no fruit. So, the fruit generally grow out farther along the cane that’s why some varieties have to be caned from and Thompson seedless is a classic example of that. How do you know whether to cane-prune or spur prune? A lot of people asked that. In the Western Garden Book and various sources, you’ll find under grape, it’ll have a table that had various characteristics of the different varieties and one important characteristic is cane versus spur pruning. And it will say for each of the varieties and so for example, Thompson seedless must be cane pruned. Flame seedless should be spur-pruned. If you don’t know and you have a vine, you don’t know what variety it is, do both spur and cane pruning and if you get fruit form on the shoots they grow up out of the spurs then you should probably be spur pruning. If you don’t get shoot fruit, they grow on the shoots coming from spurs then you should probably cane prune. Spur pruning is generally easiest. Cane pruning can be a little challenging but a lot of people do cane pruning successfully so either way is fine but just try to match it for the variety that you have.