Valient purple grapes leaves yellowing

Asked July 13, 2020, 5:31 PM EDT

My valient grape vine is quite old and has always been vigorous. This year the leaves are turning a bright yellow when they should be medium green. Is this a disease or a nutrient problem? Please help me identify this problem.

Gallatin County Montana

6 Responses

Looks like its a sulphur problem, since only on new leaves. How do I supplement with sulphur? What can I use?

I would get a soil test done, online guessing is not a good option.

Thank you for your advice. However, it seems far too brief. "Get a soil test done" doesn't really help me because I have no idea who does this, or how much it will cost. Are you able to fill me in on the details?

I gave you this link before here it is again
I don't like guessing when it comes to plant health, symptoms can be very similar.
At the end of this publication it gives a list of labs I use Midwest Laboratories, Inc. 13611 B Street Omaha, NE 68144 402-334-7770 Note: There are likely other but this one is $13.20 per sample with recommendations. take 3-4 samples with a spade down to 8" and mix them together and send off to them around the base of the grape- not under but 1-2' out trying not to cut roots.It takes about 2 cups per sample

Thank you!