How to Care for Existing Grape Vines

Install a wooden two-by-four post at the base of each grapevine after the first year. Pound each stake 12 inches deep in the ground, ensuring 6 feet remain above the ground. Extend two parallel lines of high-tensile wire along the stakes, 36 and 60 inches above the ground.

Train the canes of each grape vine to grow and spread along the lower wire and then the upper one. During the third year, select two sturdy canes for each wire and secure with elastic ties. Trim the buds on each cane, leaving two to three. Remove canes between the selected vines. Each grape vine features two or more canes at each wire in its fourth year. Select the fruiting canes and remove the others, along with suckers or shoots at the base of the plant. Afterwards, prune away shoots that grow between the wires. Collect clippings and discard to prevent fungal diseases.

Provide each grape vine 1 inch of water every week during spring and summer, unless supplemented by rainfall. Reduce irrigation frequency during the winter to only when the soil dries out. Spread 2 to 3 inches of organic mulch around the base of each grape vine to retain soil moisture and prevent competing weeds from growing around the plant. Maintain the level of mulch year round.

Feed the grape vines in spring, when the buds begin to swell. Spread 1/4 lb. well-balanced 10-10-10 fertilizer in a circle around each grape vine during the second year. Space the fertilizer 3 to 4 feet away from each grape vine. Afterwards, spread 1 lb. fertilizer in a circle, 2 to 8 feet away from the base of each plant.

Inspect grape vines for signs of pests that include insects and mites such as Japanese beetle, grape berry moth, European red mite, grape root borer and grape flea beetle. Spray insect infestations with neem oil or follow label directions for applying a fungicide.