What is the best fertilizer for grapevines

Question

I have 3 different seedless grapevine plants growing in Illinois. They get browning on the leaves and don’t produce grapes like they should, In fact, very little. They are three years old now. What do I fertilize them with and get rid of the browning?

Answer 1

When you say your leaves are browning, are they getting brown spots, or are they brown on the edges, or are they overall brown? Is there any curling to the leaves? Have you noticed any signs of pests/insects? What condition are the vines in? Is it possible the grape vines are sustaining winter injury? Browning leaves could certainly be a nutrient deficiency but I wanted to be sure all options have been considered.

If we are to pursue nutrient deficiency as the cause then I would highly recommend getting a soil test through your local extension office. Depending on the variety, a soil pH of 5.5 to 7.0 is required for proper growth and the best fertilizer will depend on your available soil nutrients as well the age of your vines. The link below will help you find the extension office closest to you:
https://www.gardeningknowhow.com/extension-search/

After you get your soil test results, you might find the following article useful:
http://www.soiltest.uconn.edu/factsheets/FertPracGrapes.pdf