How to Grow Riesling Grapes in Michigan

Dig an 8-inch-deep hole for each grape cane. Space the holes 4 feet apart. Set the roots into the hole and fan them out gently. Fill the soil around the roots and cane to hold them in place. Space the rows 7 feet apart.

Install soaker hose irrigation along each row so the hose is 6 to 8 inches from the canes. Run the irritation one to two times a week when there is no rainfall during the hot Michigan summer months. Soak the soil to a depth of 8 inches deep to assist grape production.

Spread a 10-0-0 fertilizer along the rows each spring at an application rate of 10 pounds for every 100 feet of row. Keep the fertilizer at least 6 inches away from the stem to prevent direct contact that can cause damage. Sprinkle the soil with water to promote absorption.

Spread a 3- to 4-inch layer of organic mulch around the grape stems to prevent weed growth and keep the soil moist during the hot and dry Michigan summer months. Refresh the mulch layer each spring to keep it at an adequate level.

Prune out lateral-growing two-year-old vines and one-year-old vines that appear weak and unable to support fruit growth in spring after the risk of a hard frost is over and before the buds appear on the canes.

Prune the vines after the fall harvest in October to remove about 75 percent of the current fruit producing one-year-old vines. This will stimulate new vine growth in spring.

Monitor the grapevines for scales or mealybugs. Spray the plants with a sharp stream of water to remove the insects. Mix 3 tablespoons of insecticidal soap with 1 gallon of water. Spray the mixture on the vines and foliage to keep the insects off the plants. Verify the concentration mixing rate on the insecticidal soap package. Avoid using a chemical insecticide that isn't food-safe.

Monitor the vines and grape clusters for the presence of powdery mildew, black rot and leaf spot. Control these diseases by remove the infected areas of the grapevine. Spray a liquid sulfur fungicide early in the growing season to control powdery mildew, mixed at a rate of 4 tablespoons per 1 gallon of water. Spray a copper fungicide solution after diluting 1 tablespoon of liquid concentrate in 1 gallon of water, applying up to about two weeks after bloom, to control black rot. Spray a copper or sulfur fungicide solution mixed at the same rates until about two weeks after blooming to control leaf spot. Do not apply either fungicide when the temperature exceeds 85 degrees Fahrenheit.