Midwest Grape Production Guide

Bulletin 919-05

Vineyard Establishment

Site Preparation

Preparation of the proposed vineyard site is important and should begin the year before planting. A soil test should be conducted the season before planting to provide information on soil pH status, liming, and fertilizer requirements.

If soil pH is below 5.5, apply agricultural ground limestone to raise the pH to a more desirable level (5.5 to 6.8). The application should be made well before planting time and the limestone incorporated into the soil. For highly acidic subsoils, deep-plowing with limestone is recommended.

Soil testing also will provide information on soil fertility and fertilizer needs for the first-year vineyard. Animal manures, when available, may be applied in the fall before spring planting of the vines. A suitable application is 10 to 12 tons of horse or cow manure per acre or 50 to 75 pounds per 100 square feet.

Site preparation in the year prior to planting should include land leveling, drainage tile installation (when needed), and fertility adjustments based on a soil test (Figure 21). At this time, growers also must pay special attention to controlling persistent weed pests such as thistle, Johnsongrass, quackgrass, dock, or woody species such as brambles.

Figure 21. Site preparation in the fall prior to planting in the following year. (L) Site subsoiled, plowed, and leveled. (R) Perennial grass established as permanent cover crop.

Several safe and effective herbicides are available to control such troublesome weeds in the preparation period, but they cannot be used after the vines are planted. If possible, avoid sites that are severely infested with such weeds until the weeds have been eradicated. If the available site has internal drainage problems or areas where water will pond, install drainage tile and waterways before planting (see the section on Soils and Soil Drainage).

If the area to be planted is in sod and free of weeds, at least two options are open to the grower, depending on the topography of the site. If the proposed vineyard is on a hillside or sloping ground and erosion is a consideration, an approved systemic herbicide can be applied in the fall while the vegetation is actively growing. Herbicide is applied to the row area where the vines are to be established. The row middles will remain in sod. In fall or early spring, these row areas are tilled so the sod mat or ground cover is destroyed and a friable planting soil is established.

If the proposed vineyard site is located on relatively level or gently sloping ground so that erosion is not a serious consideration, or if it is necessary to apply lime, the site should be plowed in the fall to incorporate the lime and seeded to a suitable winter cover crop. One week before plowing, apply a systemic herbicide to kill spreading roots and rhizomes of perennial weeds (see the section on Weeds and Weed Control).

Most grasses establish better if sown between mid-August and mid-September, rather than during the spring. An application of 35 pounds of actual nitrogen per acre at the time grass is sown will stimulate growth. Ordinary perennial ryegrass at 80 to 120 pounds per acre, Kentucky bluegrass at 20 pounds per acre, or a mixture of ryegrass and fescue, such as Companion grass at 20 pounds per acre, have proved to be adequate ground covers for vineyard row middles.

If ample time is available, the best results are achieved by applying lime and fertilizer, plowing, and growing a cultivated crop on the site the season before planting the vines. However, you must be certain that the herbicide used will not carry over and affect the grapes the following year. When the crop is removed, drill the grass cover crop in the row middles.

Final site preparation should be made as early in the spring as the soil can be worked, preferably in late March or early April. After plowing or tilling, apply and disk (or till) the required fertilizer into the soil before setting the vines.

Even though early spring preparation is advisable, it should not be done until the soil is dry enough to work properly. If soil is worked too wet, the advantages of early preparation will be lost because soil structure may be damaged. The effects of a puddled soil, particularly one with high clay content, may result in poor vine growth for a number of years.

Vineyard Design

The vineyard should be designed to achieve the following goals:

• Prevent soil erosion—the most important goal.
• Use land area efficiently.
• Optimize vine performance.
• Facilitate management and equipment operation.

Vineyard rows need to be straight for trellis strength. On sloping land, rows should be across or perpendicular to the slope. It may be necessary to divide the vineyard into blocks to accommodate depressions or other characteristics. If erosion control can be accommodated, it is preferable to orient rows north-south. This orientation provides the most even distribution of light in the canopy and has been associated with improved yields and berry quality.

Row spacing depends in part on the proposed training and trellising system and the equipment to be used in the vineyard, such as a mechanical harvester. Nine- to 10-foot spacings between rows are common and generally ample, but 11 or even 12 feet between rows may be needed to accommodate divided training systems (e.g., Geneva Double Curtain), large equipment, or steep slopes. An 8-foot spacing between rows is satisfactory for small plantings, but this is considered too restrictive for most commercial operations. In general, as distance between rows increases, yield per acre decreases.

Spacing vines in the row at 8-foot intervals has proved satisfactory for average conditions. However, closer spacings have produced higher yields under certain conditions. Cultivars that produce less vigorous growth, such as Delaware, some French hybrids (Seyval and Chambourcin), and some vinifera, may be set closer together than Concord or others of similar vigor. Highest yields generally have been obtained from vineyards containing 600 or more vines per acre.

To create conventional, straight rows, establish a baseline along the edge of the field. Drive a stake at each end of the proposed line. Generally, these stakes are located by measuring a desired distance in from the edge of the field to allow turning space for equipment. By sighting from one stake to the other, additional stakes are placed on the baseline to mark it. A careful tractor operator can plow a furrow along the baseline, which also serves as the first row of grapes.

There are several ways to establish rows parallel to the baseline or first row. A simple way is to establish a perpendicular line at each end of the row. First, set a stake on the baseline 30 feet from the end. Then, place a stake 40 feet from the end of the baseline on the assumed perpendicular line.

Measure the angular distance between the 30- and 40-foot stakes. If the distance is 50 feet, the assumed line is correct and can be extended by sighting. If it is not, move the 40-foot marker—not the 30-foot marker—until there is 50 feet between the two stakes. Stakes can be driven on this second base at the proper intervals to indicate the row ends.

The procedure used to mark the baseline is repeated until the required number of rows has been marked. A pole the length of the desired interval between vines can be used to space vines in the row as they are planted. However, a planting chain with lead markers at designated intervals is much more accurate.

It is important to leave enough space at the end of rows for machinery to turn. A 25- to 30-foot headland at each end of the vineyard should be adequate. It also is important to leave sufficient space on the sides of the vineyard to allow easy movement of equipment. If rows are long, 20- to 25-foot-wide crossing alleys at about 500-foot intervals will ease vineyard management.

Polyethylene Mulch Application

Black polyethylene mulch has been used successfully in establishing new vineyards. However, the introduction and the availability of approved pre-emergence herbicides and the increased cost of plastic have reduced its use. Its popularity may return if herbicides are withdrawn or become unavailable to growers.

The planting procedure begins with thorough tillage of the row areas. One week before tillage, or earlier, apply a systemic herbicide to kill spreading roots and rhizomes of perennial weeds. A rotary-type tiller is recommended for soil preparation. Fertilizer and/or lime can be incorporated into the soil during tillage, as recommended by soil test results.

When the row is properly prepared and the fertilizer thoroughly tilled in, roll black plastic over the row, pull it tight, and hold the edges down with a small ridge of soil. Laying the plastic mulch is easy with modern equipment and requires little or no hand labor. In small plantings, lay the plastic by hand in a similar manner. Ordinary black plastic, 3- to 4-feet wide and 1.5 millimeters thick, is satisfactory.

After the mulch is in place, mark off the plant spacings and set vines through the plastic. Plastic should be laid down well ahead of the planting. It is advisable to lay plastic when soil moisture conditions are near ideal because the soil dries slowly beneath the plastic. As soon as mulch is laid on some of the rows, planting can proceed as rapidly as possible, even on days when mulch laying or tilling is not advisable.

Vine Preparation and Planting

Handle young vines carefully to prevent drying out or other damage after they have been dug or received from the nursery. If dormant vines are not planted immediately, place them in cold storage (32°F with high relative humidity) until planting time.

If proper facilities are not available, carefully heel-in vines in a sheltered location. To heel-in plants, dig a shallow trench and place vines in the trench so the tops are exposed. Cover the roots with soil and firm the soil. If the soil is not moist enough, water newly set vines to prevent the roots from drying out.

Vines should be transplanted to their permanent location as soon as possible. Soaking dormant vine roots in water two to three hours before planting also will increase their chance of survival.

Early spring is the most suitable time for planting grapevines in the Midwest. Fall planting generally is not recommended because fall-set plants are likely to be lost to heaving during the first winter. If plants must be set in the fall, plow a 4- to 6-inch mound of soil around the base of the young vines, or mulch them with straw to protect against heaving and severe cold.

Do not prune roots except to remove broken or dead portions. Plant as much of the root as possible, ensuring good distribution in the trench or hole. Most of the reserves of the vine are stored in the roots and to ensure maximum growth, plant as much of the root system as possible. Normally vines purchased from a commercial nursery have been pruned, but if not, they should be pruned to a single cane.

It is critical to keep vine roots moist during planting and transporting to the field. Grafted grapevines should be set in the hole with the graft union several inches above the soil line and soil firmed around the roots. After soil settling, the graft union should be 2 to 3 inches above the soil line. Setting too deep will result in scion rooting and loss of phylloxera resistance of the rootstock. Non-grafted vines should be set with the junction of the older wood and new canes at the soil line.

To plant, plow a straight furrow 10 to 12 inches deep for the row. This depth will accommodate a large root system without packing a mass of roots into a small hole. Spread roots well, cover with a few inches of topsoil, and tamp firmly. A plow or disk may be used to finish filling the furrow. A short, 9- to 12-inch diameter, tractor-powered posthole auger also can be used for planting. In small plantings, the entire operation can be done by hand. In large operations, a commercial vine-planting machine often is used. (See Figure 22.)

FIGURE 22. A tree planter is best used in large planting operations.

When planting is completed, the node from which the lowest cane will arise should be at or just above the soil level. Prune the single cane remaining after planting so that only two or three live buds remain. Some growers prefer to leave five or six buds. As these shoots develop, all but two of the most vigorous are removed when about one-inch long. This pruning provides two shoots to develop into vigorous new canes. (See the Pruning and Training section on handling young vines and the use of grow tubes.)

If polyethylene mulch is used, a common planting procedure is to force the long, narrow blade of a tilling spade through the plastic into the soil to a depth of 10 to 12 inches. The opening is widened by a back-and-forth motion, leaving an open hole. Insert the dormant vine and tamp soil firmly around the new plant. When vines are grown in pots or similar containers, an ordinary hand-type posthole digger is useful. After planting, pull the plastic closed around vines and place a small amount of soil on the surface.

Trellis Construction

Constructing the trellis can be the greatest cash expense in vineyard establishment, and it must be strong enough to carry heavy fruit loads and withstand strong winds. The trellis must be durable, and its real cost is determined by years of service, rather than initial cost. The physiological function of the trellis is to expose foliage and fruit to sunlight, and generally, the higher the trellis, the more foliage will be exposed and the more productive the vineyard. The best time to construct a trellis is during the first growing season or the following spring before growth begins. Waiting beyond this time will result in delayed harvest of profitable crops.

End posts should be large (4-1/2- to 6-inches diameter) and longer than line posts (9 to 10 feet instead of 8 feet) because they must serve as anchor points as well as wire supports. Copper-salts-treated pine, locust, and other suitable posts are commonly used. Posts should be pressure-treated as they will last 10 to 15 years longer than posts dipped in the same preservative. Set end posts about 3 feet in the ground and at a slight angle with the top leaning away from the direction of the row. The top should extend at least 6 feet above ground level after setting to support the top trellis wire at the desired height.

End posts can be braced in several ways. A common method is to set a screw anchor a few feet outside the end post. The angle of the wire attaching the anchor to the post should be about 34 degrees (Figure 23).

FIGURE 23. End posts are set 3 feet in the ground at a 60-degree angle and anchored with a screw-type steel anchor.

Another bracing method uses a brace wire from the top of the end post to a dead-man anchor in place of the screw anchor. The dead man is buried 36 to 48 inches from the post. A double-wire brace extends around the post near the top and to the anchor. The brace is tightened against the anchor by twisting the wires together. Other types of braces with the guy wire are available.

Line posts generally are cut 8- to 9-feet long with a minimum of 3-inches diameter at the top. They are set 24 to 30 inches deep and spaced 20 to 24 feet apart in the row. The exact spacing depends on vine spacing. It is suggested that posts be driven with a post pounder because it takes less installation time, and a driven post is more stable than a post set in an augured hole.

High-tensile-strength steel wire is becoming popular in newly set vineyards. Its strength and durability are in several ways superior to conventional wire. Because this wire has much greater tensile strength (200,000 psi), it must be handled differently than regular iron or galvanized wire.

Galvanized 9-gauge wire was the standard for many years. While high-tensile steel wire is initially more expensive than galvanized wire, it is more durable and may be the most economical over a long period. Rusted wire can seriously chafe vines. High-tensile-strength steel wire should have Class III galvanizing, and a wire gauge of 11 to 12.5 is acceptable, with 12.5 gauge most commonly used. The number of wires and their location depend on the training system.

The length of wire needed for an acre of grapes depends on row spacing, the gauge of wire used, and the training system. Wire is generally sold by weight, and the length in feet for 100 pounds of the following gauge wire is: 11 gauge = 2,617 feet; 12 gauge = 3,300 feet; 12.5 gauge = 3,846 feet. The weight of wire needed for a single wire at various row spacings is shown in Table 6. The weight needed for additional wires required by the training systems can be multiplied using the weight for a single wire.

Wires may be secured to end posts in various ways. A common method for galvanized or iron wire is to wind the wire around the post once or twice and then twist the end several times around the wire as it is stretched to the next post. Special devices also are available to attach the wires to the posts. These devices simplify adjustment of the wires by using a crank or a cinch that eliminates removal of wires from end posts when tightening or loosening. If high-tensile-strength steel wire is used, a special wire-crimping tool is required. There are also several types of wire anchors and connectors specifically designed for high-tensile wire.

Wires are fastened to line posts with ordinary staples or inserted in holes drilled in wooden line posts. The staples must be driven deep enough to hold the wires close to the post, but with enough play that the wire will slip through when tightening is needed. Staples are less likely to pull out if wires are hung on the windward side or the uphill side of posts. With steel posts, regular fence wire fasteners are used.