Help: Grape leaves turning yellow?

brumer0May 6, 2012

Hello everybody!

This is my second year growing grapes and am hoping to get an actual harvest this year (3yr old vines). I live in NC and have a drip system on my grapes, so there isnt a bunch of water getting on the leaves/fruit. I also spray every 2 weeks with Sevin and this other anti-mold/fungus stuff.

Below are 2 links to the pictures of some grape leaves I have (one is the top and the other picture is the bottom). Can you help me identify whats wrong? Am I over/under watering, soil deficiency, or disease? I dont see any mold or fungi, but I honestly might not be able to recognize such things bc I am a newb. Or, is it just time for these leaves to die. Id say 5-10% of the leaves are turning this color.

Thank you!!!

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luis_pr(7b/8a Hurst, TX)

I would check for Magnesium deficiency, Potassium excess and soil pH problems. You will need to make a soil test for Mg deficiency though. There are some cheap soil test kit that will check for Pottasium and soil pH levels. There could also be pests involved as well as growing the vine close to a black walnut tree (the juglone in the roots is toxic to many plants).

    Bookmark   May 6, 2012 at 5:49PM
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jean001a(Portland OR 7b)

Could be water related.

What's the output of your drip system for the grape?
How long do you run the system.
How often do you water?

Please post an image of the vine overall.

    Bookmark   May 7, 2012 at 12:44AM
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That's funny I just planted one from one of the big box stores 3 weeks ago at the end of the first week that's how my leaves looked, I just kept on watering on a normal routine of any newly planted plant checking the soil for moisture the leaves never wilted or fell off, now they are almost completely greened back up.

    Bookmark   May 7, 2012 at 7:27AM
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Thanks everybody for your continued help.

luis_pr: Thanks for the mg idea. I did a lot of research and noticed that mg deficiency makes the area between the leaf veins turn yellow first. It appears that the veins in my leaves are turning yellow first (opposite). Not sure it it actually matters. Ill keep the mg as a possibility.

jean001a: I have one dripper per vine, doing 2 gallons per hour, and watering 1 hour every morning. If anything, I feel that this is too little water. Am I wrong? I have about 12 inches of sand on top of the soil, followed by probably 60% clay under that. Prior to planting last year I rented a trencher and dug 36" deep over the planting rows, which mixed stuff up a bit.

    Bookmark   May 7, 2012 at 8:11AM
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fruitnut Z7 4500ft SW TX


Watering every day on soil with 60% clay could be your issue. In NC with decent soil you shouldn't need to water a grape except during long dry spells. If you do find a need to water no more than once a week.

    Bookmark   May 7, 2012 at 9:35AM
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Scott F Smith(6B/7A MD)

I would put overwatering as your #1 potential problem, mineral deficiency as #2, and Pierce's Disease as #3. Your damage looks something like Pierces Disease but seems to symmetrical.

12" of sand is something I never heard of on grapes, that could also be an issue. Where are the roots if you have 12" of sand on top? 100% sand is a really bad growing medium if the roots are in the sand layer. In general you seem to be over-thinking the whole thing here, unless there is some significant problem with your location that you have not mentioned. I just take my grapes and stick them in the ground. They get fertilizer, mulch, and compost once per year.


    Bookmark   May 7, 2012 at 9:53AM
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    Bookmark   May 7, 2012 at 1:55PM
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