I bought some seedless grape vines and planted them. I’m thinking ahead to when they will need to be pruned.
In Northern Italy where I live, they prune grape vines differently than what I’ve seen pictured on the internet for how it’s done in the U.S.
The first pic is near my home and the other is an example of spur pruning.
What do you think? Which should I go with?
The best pruning style in grapes is a combination of personal choice and the vigour of the site. In general, cane pruning systems are a little less prone to trunk diseases because there are fewer pruning wounds for pathogens to enter, but they aren’t easily mechanized and require more hand labour if that’s a concern. Cordon pruning styles tend to be better for mechanized systems. Some systems like head training are really only useful on low vigour sites or they turn into a tangled, shaded mess. Other systems like Geneva double curtain are only useful at high vigour locations.
If you’re not sure, probably the safest thing to do is to go with what is common in your area. It’s highly likely that will work at least reasonably well. If you’re more individualistic, study the strengths and weaknesses of some of the common systems and pick one you think would be best suited to you and your location.
Since your grapes are seedless, they have ancestry from Thompson Seedless and may need to be cane pruned to be productive. Many Italian wine grapes have low basal bud fertility and are cane pruned as well.
Which varieties do you have?
Supernova, Crimson seedless and Argentina. I assume Crimson seedless is a U.S. variety but not sure about the others…
Supernova
Supernova is half Thompson and will most likely need cane pruning. The one in the photo you found is cane pruned.
Thompson ancestry is a little further back in Argentina and Crimson Seedless, so they may or may not need it. That photo of Argentina also looks cane pruned. Crimson Seedless is more productive with cane pruning but can produce an acceptable crop when spur pruned. For ease of management you may just want to cane prune all three.
As far as I know all varieties tolerate cane pruning but not all varieties tolerate spur pruning. If you could get quality fruit with only spur pruning then cane pruning wouldn’t exist. Cane pruning is labor and expertise intensive and prone to mistakes. People only do it if it’s the only option for their variety.
Some nurseries list how each variety likes to be pruned in the description. If you’re not sure you can leave canes the first year and if most of the growth is from the first two buds then the variety is probably fine for spur pruning.
I’m not familiar with any of the varieties you list so I can’t tell you what they prefer. Table grapes tend to prefer cane pruning and using a spur-based system will give you low quality fruit.
That won’t tell you whether or not a variety is fine with spur pruning. You need to count the number of clusters on the shoots growing from those buds to find out, provided the vines are old enough to flower and the buds received enough sun to initiate clusters in the previous year.
I found this page about Supernova. They said it originates in Moldavia…Grape variety and grafted vine plant Supernova Seedless: all the secrets - Vivai Rauscedo
This is much more accurate than what I wrote.
I love this site. I write something I think almost nobody knows about grapes and a grape nut from Napa shows up right away and writes something better. Awesome.
Growing my Shine Muscat, Ruby Roman and Queen Nina goblet style.
So basically make sure most of the fruit on the canes originate from the first 2 buds? Then it would be ok to spur prune because you won’t lose much fruit?
I know from harvesting the wine grapes here in Italy that most of the fruit is actually way down the cane near the ends but who knows if it’ll be the same for these seedless varieties
Once your vines reach the fruiting wire on your trellis, usually the end of the second growing season, you’ll be tying a cane or two down. These will be your fruiting canes for the following season if you are cane pruning, or the future cordon if you are spur pruning. When the buds on those canes start growing the next spring, count the number of clusters on each shoot. There should be 1-2. If it’s less than 2 on the shoots arising from the first two or three buds, that variety probably isn’t well suited for spur pruning. You may want to observe for a few years before committing to a pruning style since vines can take a couple years to start flowering. It’s easy to switch to spur pruning from cane but not the other way around.
A lot of Italian wine varieties have low basal bud fertility and need to be cane pruned. Same goes for a lot of table grapes. Commercial table grape growers are usually trying to maximize yield, so they typically cane prune even if the variety can be spur pruned since yields will be higher.
Just checking if i understand correctly. (if learned grape pruning in a different language so not sure if i got all the terms correctly)
Spur pruning, is what you do with cordon trained grapes right? Where the horizontal structure where canes grow from is permanent.
cane training (like guyot training?) is where you only have a vertical permanent structure and use new 1y old shoots (canes) to bend horizontal each year.
From the horizontal parts you grow vertical shoots those shoots contain the fruit.
Some grape cultivars (like Italian wine grapes) have low fertility on the first few buds on the cane. And buds more towards the middle or end have better flower fertility? that’s why you cane prune them. (cane prune like Guyot?)
I must admit if not been diligent on grape pruning for my vines. But if always cane pruned them. Since the internode spacing from cane pruning and bending those left over cane(es) horizontal gave good sunlight/fruit combo. I try to remove every second cluster from the shoots that arise from the cane. (most of my grapes produce 2 (3) clusters of fruit from each shoot that grew from a cane internode.
i know a hobby wine grape grower. He always counts the number of buds when cane pruning (guyot pruning). Do you have any advice on that?
Not everyone agrees on the English terms either, and some pruning/training styles are highly specific to certain regions.
Yes, although you can spur prune vertical/head trained vines (gobelet in France, alberello in Italy, bush vines in Australia).
Correct, but in a high vigor site with table grapes there’s no reason why you can’t train out canes from multiple permanent branches.
Correct. The first 2-3 buds on a given cane of these varieties will produce shoots with no or very few clusters, so spur pruning would remove the most fertile buds.
That sounds right. One thing to keep in mind though is that the clusters for next year are formed in late spring/early summer of the current year, so light exposure during flowering is more important than later in the season. Grapes don’t need full sun on their buds to initiate clusters though. Dappled light from removing lateral shoots and suckers is enough unless your vines are very vigorous.
The vast majority of grapes produce 2 full-size clusters per shoot. Some will produce a smaller 3rd cluster. With table grapes, since many of them have large clusters, thinning to one per shoot is fine, or alternatively, removing half or more of both clusters so the vine doesn’t overbear and to improve airflow.
You can control vigor and production by leaving more or fewer buds. For example, if you pruned to a 10 bud cane last winter and the vine grew poorly (new canes less than 3ft/1m long), you can prune to 6 or 7 buds instead. If you know from experience that your winters are cold enough to kill some of the buds, you can leave longer canes to compensate.
