Planting and Care of Young Grapevines
Planting Site: Plant in full sun if possible, or in an area with at least 6 hours of sun exposure. Decreasing the hours of sun can affect grape quality and increase the disease incidence. Construct an arbor or trellis to support the vines. Plant where the soil is at least 2 ft. deep, preferably where there is no compacted soil layer below.
Planting the Potted Grape: Dig a hole twice as wide as the plant's container. However, if the soil is compacted, make the hole up to 3' in diameter. Make the hole about as deep as the grape was growing in the container. Carefully remove the grape plant by squeezing the sides of the pot and then turning the pot upside down with your hand supporting the soil. Plant the grape using the soil that was removed from the original hole. Amendments are not needed in the planting hole. Water the soil thoroughly.
Staking the Vine: Attach the new vine to a stake, post, or arbor as it grows the first year; green plastic tape works well. Tying the new shoot will ensure a straight trunk.
Watering the Vine: Keep the soil around the new vine moist but not constantly saturated. Check for moisture with your finger or dig down into the soil. Once established and growing well, water deeply and less frequently, about weekly if flooding or bi-weekly if drip irrigated. Use mulch to reduce soil moisture loss.
Fertilizer: No fertilizer is needed at planting time, and very little nitrogen if any is needed later. Too much nitrogen promotes excessive vegetative growth, which can cause diseases and poor grape quality.
Pruning: If first year growth is slow, cut back the vines to only two healthy buds in the winter after the first growing season. Train the most vigorous shoot up the stake to form the trunk, and prune out the weaker of the two shoots. The variety of grape determines the type of pruning (spur or cane) to use. Consult The Sunset Western Garden Book to determine the right pruning method.
Pest Management: You can expect to encounter the disease powdery mildew, and sometimes bunch rot. Powdery mildew can show up as a white powdery coating on all parts of the plant. It is often not necessary to control it the first season because there is no fruit. Powdery mildew can be controlled by spraying or dusting with sulfur beginning in the spring when the new growth is about 1 inch long and continuing at 7 to 10 day intervals through June. Bunch rot occurs when a fungus or bacteria gets into a damaged fruit. These rots can be controlled by removing the leaves around the clusters on the north or east sides when the grapes are the size of peas (usually early June). Erineum mites are microscopic pests that cause large, puckered spots on leaves. The underside of the pucker is initially white and furry, and turns brown in the summer. The problem is cosmetic only and does not reduce fruit production or quality. Control with insecticidal soap early in the season. Where early treatments of sulfur are applied to control powdery mildew, erineum mites are seldom seen.
July, 2004. Written May, 2003. Written by UC Master Gardeners Cathy Coulter, Rose Gong, Art Svejda, and Elizabeth Wise. Edited by Chuck Ingels, Farm Advisor and Judy McClure, Master Gardener Program Coordinator, UC Cooperative Extension Sacramento County.
Extensive information about growing grapes from the California Garden Web.