Grapes are sold as rooted cuttings (referred to as "own-rooted" plants) or grafted plants. Both usually are sold as bare-root dormant plants. Only the European grapes require grafting since they are susceptible to the root louse phylloxera, which is ubiquitous in our soils. Grafting onto a resistant rootstock takes care of this problem.
Most grape plants will be rooted cuttings, but note that grapes are also propagated easily from dormant cane cuttings. Collect dormant wood (pencil thickness, exposed to full sun) in December and store it in a cold, but not freezing, place until spring, making sure to note which end of the cuttings is "up." The plants will not root if put in the soil upside down. In the spring, put two nodes of the cutting into friable, moist, well-drained soil, and keep the cuttings watered. Rooting generally will occur in 4 weeks or so. Transplant the following spring to the desired site.
Regardless of whether you buy or propagate your own plants, plant them in a large hole with the roots 4 to 6 inches below the soil surface, pruning off damaged roots and spreading the remainder. Prune back to one cane, and leave only two to three nodes on each cane. After shoot growth begins and the danger of spring frost is past, remove all but the two strongest shoots (Figure 6.1). Be sure to keep the new vines watered and weeded, and remove all flower clusters in this first year. Remember that your first goal is to establish the plant. A well-established grapevine that is well adapted to its climate will produce fruit for 50 years or more! Vines can be staked as needed, and the desired trellis system can be erected during the summer or the fall. How the plants are supported is up to the individual, of course; the grape plant adapts graciously to most forms. A standard trellis used in commercial vineyards is about 6 feet tall, with wires at 3 and 6 feet to support the grapes. Be sure to monitor and control insect and disease pests.
Test and amend the soil according to the soil test directions a year before planting.
Two to three weeks after planting, apply 2 ounces of 33-0-0 to the plants, taking care to keep the fertilizer 1 foot away from the vine. In subsequent years, apply 4, 6, or 8 ounces of 33-0-0 per plant or 1 to 2 pounds of 10-10-10 per plant before the buds start to swell in the spring. If vines are too vigorous, omit nitrogen for 1 to 2 years. Test the soil periodically (every 3 to 5 years) and maintain a soil pH between 5.6 and 6.4.
Herbicides currently registered for use in commercial vineyards are not recommended for home gardeners. Physical control of weeds under the trellis by mowing, cultivation, hand hoeing, and pulling is suggested. Growth in row middles should be controlled by mowing.
General Insect and Disease Control Suggestions
- Use varieties and rootstocks resistant to root louse (Phylloxera).
- Prune to keep the vines vigorous.
- Prune off and dispose of all dead, diseased, and broken parts.
- Rake the soil clean under the vine and remove old and shriveled fruit from the vine before spring growth starts.
- Identify insects and diseases accurately.
- Spray when necessary. Table 6.5 and Table 6.6 provide information about the use of pesticides on grapes.