The Best Fertilizer for Concord Grape Plants

Animal Manure

• If you decide to use organic fertilizer such as animal manure, make sure it is well composted or "rotted" to avoid potential burning of your Concord grape's roots. Steer, chicken and other animal manures are available commercially in large bags at all garden supply stores. Do not over fertilize your grape vine: Oregon State University recommends fertilizing grapes once sparingly during Spring. You can make compost tea from animal manure or scatter it on the soil surface about 8 inches from the trunk, avoiding touching the trunk with the manure.

Compost and Worm Castings

• Other organic fertilizers that work well for grapevines include compost and worm castings. You can make your own compost from chopped up plant parts, lawn clippings, fallen leaves, rotten food and other organic materials. It is also available in bagged form at garden supply stores. Spread a 2 to 3 inch layer of compost several inches from the base of your grapevine in a doughnut shaped. Repeat this application at least once each year. To use worm castings, dissolve 1 cup of castings in 1 gallon of water and pour the mixture into the soil around your Concord grapevine once a year.

Commercial Plant Food

• You can select a balanced plant food that has an N-P-K ratio of 10-10-10 or an N-P-K ratio of 10-20-20, according to Ohio State University and Oregon State University. If you use a 10-10-10 plant food, apply 8 oz of this product one week after you first plant your Concord grape. One year later, give your grape 1 lb of fertilizer and in its second year, give it 1-1/2 lbs, following label instructions for mixing and applying it. It's best to fertilize early in the Spring before new growth begins to emerge. If you use a 10-20-20 fertilizer, apply 10 oz of the product in early in the Spring. It is important to avoid over fertilizing your Concord grape vine.