high yields, when is high too high?

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Obbnw

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My pruning method is controlled chaos, with the main goal of having a green wall and keeping the vines out of the driveway and the neighbors yard.

I've mostly been letting my vines produce as much as they want. Last year a few of the vines produced over 40lbs of grapes. Quality seemed fine, and all ripened. This year the number of potential clusters is huge - trying to decide if I should just let them go or thin them out.

Anyone have experience with high yields? For reference the spacing is about 4' and driveway to top wire is about 10', no true "fruiting zones" although I tried to develop a bottom, middle and high zone. I bet I'm looking at 30 to 40 lbs for the 4' spacing vines and 50 - 60 lbs for the ones over the garage. Half are Malbec's, half are Tempranillos.


I also selectively harvest, IE I don't always pick all the grapes off a plant at once, clusters that appear behind I leave on. Last year harvest started on 9/10 ended on 10/1. Brix on all the pickings was pretty consistent 24 to 25, ph varied from 3.65 to 4.1. The climate and soil here are conducive to high PH.

I haven't noticed a quality difference between low yield vines (as low as 10lbs) and the high yield plants. The plus 40 lb vines are over the garage and have much more room to spread out. Tip to tip is close to 25'.

Right now I think I'll let them go, monitor progress and if the appear to be lagging thin in August.

I am curious on opinions though.

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Obbnw

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Did some vine control work over the past few weeks. There are definitely tons of clusters. Plus so far this year we've been a little cooler than normal, fruit set seems delayed.

I was going to wait to thin until after fruit set, but I read an article about thinning and it said that for highly vigorous vines berry size compensation wasn't as big a concern.

I'm going to thin some now, thin some in about 4 weeks and leave some "as is", see how they all do. "As is" means mostly unthinned but when I find some clusters back against the wall/fence with the shoot struggling to find sun I'll remove the whole shoot.

If you zoom in you see all the clusters/flowers. I'll trim the right leave the left alone (2 plants overlap at the support post).

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VinesnBines

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I need to 1. Do my homework on which of my varieties MUST be cluster thinned; 2. Wait for the clusters to form completely and 3. Determine which clusters to drop. I'm planning to get the thinning done early because we will be netting early. I think most of my vines will need cluster thinning this year. Everything is early and heavy bloom.

I know some commercial vineyards don't drop fruit until late in the season.
 

Obbnw

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you will probably want to at least thin some leaves so you can spray the clusters and help everything dry out.
I usually trim them and leaf pull a little every day. This year I've had a bunch or other stuff intruding into my gardening time so they are a little thick. Maybe today ; )

That said, I only spray once a year in May for powdery mildew. The spray is a mix of "Cease" and "Milstop". It is so hot and dry here I don't have much disease pressure. Its 82 degrees right now and the 30% RH feels humid for here...
 

VinesnBines

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That said, I only spray once a year in May for powdery mildew. The spray is a mix of "Cease" and "Milstop". It is so hot and dry here I don't have much disease pressure. Its 82 degrees right now and the 30% RH feels humid for here...
Wow. Even my most disease resistant hybrids need spray - I'm worrying about a two week gap between sprays.
 
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Spray regimes depend on the region/climate. In a west coast dry climate, one or two sulphur applications may be enough. In areas with more humidity/rain, it is likely very different.

The vines look good to me. As for thinning, as long as your source-sink is in balance you are fine with heavy loads of grapes. If you worry about overcropping, you can measure using the Ravaz index, where you compare pruned shoot weight at the end of the year to the cluster yield. Generally 5 ~ 8 is healthy (cluster weight is 5 ~ 8 times the pruning weight), more than that can stress the vines (although in the San Joaquin Valley they sometimes go above 10). Not sure if you want to get that into it or not.

You do want to do leaf thinning to open up the canopy. It is good for the clusters will improve next year's shoots. You can control growth through deficit irrigation if you want. I believe Salt Lake City is pretty dry in Summer, correct? Deficit irrigation up to verasion will also lead to lower IBMP levels (bell pepper taste) in your final product.
 

Obbnw

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Spray regimes depend on the region/climate. In a west coast dry climate, one or two sulphur applications may be enough. In areas with more humidity/rain, it is likely very different.

The vines look good to me. As for thinning, as long as your source-sink is in balance you are fine with heavy loads of grapes. If you worry about overcropping, you can measure using the Ravaz index, where you compare pruned shoot weight at the end of the year to the cluster yield. Generally 5 ~ 8 is healthy (cluster weight is 5 ~ 8 times the pruning weight), more than that can stress the vines (although in the San Joaquin Valley they sometimes go above 10). Not sure if you want to get that into it or not.

You do want to do leaf thinning to open up the canopy. It is good for the clusters will improve next year's shoots. You can control growth through deficit irrigation if you want. I believe Salt Lake City is pretty dry in Summer, correct? Deficit irrigation up to verasion will also lead to lower IBMP levels (bell pepper taste) in your final product.
Thanks for the input. Just got in from trimming/thinning about 2/3 of the grape plants, will finish the rest this weekend. Pulling leaves and removing buried shoots, etc.

It is quite dry here, average rainfall in June, July, and August is probably less than 1/2" per month. Soil is a lake bed clays with gravel seams. It really seems to hold a fair amount of water. I've been surprised how well the grapes do without water.

Last year I had about 500 lbs of grapes, I never weighed the pruned material but I would be shocked if it was less than 50 lbs. I'll have to weigh my green waste bin tomorrow, and after it is emptied. I bet I fill it 5 times a year.
 
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Clay holds an incredible amount of water if the roots can penetrate the soil. Ravaz Index is the most precise way to measure vigor, but I have had trouble using it. IMO it is a good way to track vigor over time in an established vineyard where the manager wants to try adjusting irrigation effects. You are growing vitis vinifera. What I would do is drop all fruit off canes less than 18" long or have not reached pencil thickness, 1 cluster for canes between 18" and 24", two clusters for canes longer than that. If you have very vigorous vines, tie a "kicker cane" pointing down to the trunk or irrigation line which will slow the auxin flow to the shoot tips. Then cut it off around the end of July. The vine growth is a bit random compared to a trellis, and shaded on one side, so you will have to use judgment.
 
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Obbnw

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Clay holds an incredible amount of water if the roots can penetrate the soil. Ravaz Index is the most precise way to measure vigor, but I have had trouble using it. IMO it is a good way to track vigor over time in an established vineyard where the manager wants to try adjusting irrigation effects. You are growing vitis vinifera. What I would do is drop all fruit off canes less than 18" long or have not reached pencil thickness, 1 cluster for canes between 18" and 24", two clusters for canes longer than that. If you have very vigorous vines, tie a "kicker cane" pointing down to the trunk or irrigation line which will slow the auxin flow to the shoot tips. Then cut it off around the end of July. The vine growth is a bit random compared to a trellis, and shaded on one side, so you will have to use judgment.
As I've been trimming the vines, I have been removing the short shoots, weak shoots, crowded shoots and the late bloomers.

I googled the Ravaz index, I misunderstood at first and thought it was summer pruning weight not winter pruning weight. I'll pay more attention to winter pruning this year. Previous years I haven't done a lot of winter pruning since I've been letting the vines spread out. This year all the vines have gone about as far as I want so I expect this years winter pruning to be more volume. Previous years Ravaz index is probably close to 20.

It's tough to compare "vineyard" systems and yields to my plants since mine are more like a pergola trained system.

I appreciate the input.
 

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