VSP — Vertical Shoot Positioning

Vertical Shoot Positioning is a vine training system where actively growing shoots are directed upward in a narrow, vertical curtain of foliage, with the fruiting zone positioned below along a fixed cordon or cane wire. The system was first adopted in cool-climate wine regions including Germany, France, and New Zealand, where the dual goals of maximizing limited sunlight and reducing fungal disease pressure made an open, vertically organized canopy essential. In these regions, VSP keeps vine foliage away from the soil and positions it to facilitate both hedging and spray application. The system spread to California during the planting boom years of the 1990s, where it was embraced by premium coastal producers, particularly for Vitis vinifera varieties whose natural upward growth habit makes them ideally suited to the system.

• First used in cool areas including Germany, France, and New Zealand to manage fungal disease and maximize sun exposure
• Adopted widely across California during the 1990s wine industry expansion and now dominant in premium coastal AVAs
• Particularly suited to Vitis vinifera cultivars, whose natural upright growth habit aligns with the system's vertical orientation
• The Guyot training system, developed in France and widely used in Bordeaux and Burgundy, is considered part of the broader VSP family of systems

A standard VSP installation consists of a static cordon wire installed approximately 3 feet above the ground, which supports the vine's permanent woody arms, plus multiple pairs of movable catch wires positioned above it. A complete system typically uses four to six levels of wire in total, creating a vertical foliage curtain typically around 48 inches tall with 12 to 18 nodes per shoot. Early in the growing season, after shoots are sufficiently long, the catch wire pairs are moved from below the cordons or canes to positions above them, sandwiching the foliage into an upright, narrow panel. Wire moving and locking are normally manual operations, though mechanical wire placement with temporary clips is also possible. Regional configurations differ: in California, the fruiting wire sits at roughly 100 to 110 centimeters, while in Champagne it is positioned much lower at 20 to 30 centimeters, reflecting local climate and AOC requirements.

• Cordon wire typically installed around 3 feet above the ground; catch wires above guide shoots into a vertical plane
• Four to six wire levels in total, creating a foliage curtain roughly 48 inches tall with 12 to 18 nodes per shoot
• Catch wires are moved manually early in the growing season to sandwich lengthening shoots into the vertical panel
• Regional fruiting wire heights vary considerably: approximately 100-110 cm in California, 55-60 cm in Piedmont, and 20-30 cm in Champagne

VSP works by training shoots vertically so that the fruit at the base of each shoot is pushed to the outside of the canopy, directly increasing cluster exposure to sunlight and enhancing ripening. The upward orientation also creates a large leaf surface area well exposed to sunlight, enhancing photosynthetic capacity. By keeping all vegetative growth above the cordons and in a single organized plane, VSP eliminates the shading that leads to herbaceous flavor compounds, poor color development, and uneven ripening. The improved air movement through the fruit zone is particularly important for disease management: a well-thinned VSP canopy reduces humidity levels and accelerates canopy drying after rain, creating an unfavorable environment for powdery mildew, downy mildew, and botrytis. The system also improves the penetration and coverage of spray applications, reducing reliance on fungicide inputs.

• Fruit at the base of each shoot is pushed to the outside of the canopy, increasing direct sunlight exposure on clusters
• Upward orientation creates a large expanse of well-lit leaves, enhancing photosynthetic capacity throughout the growing season
• Improved airflow and faster canopy drying reduce conditions favorable for powdery mildew, downy mildew, and botrytis
• Open canopy structure improves spray penetration and coverage, reducing the number of fungicide applications needed

Effective management of a VSP system requires multiple labor passes through the growing season. Shoot thinning is a primary task: in VSP and high cordon systems, shoot density should be managed to approximately three to five shoots per linear foot of trellis to maintain good airflow and light penetration. Shoot positioning begins once shoots are long enough to tuck into the catch wires and continues through the early stages of fruit development. Leaf removal, particularly in the fruit zone, is often practiced to improve cluster light exposure and air circulation, though in high-sunlight climates such as inland California, leaf removal on the afternoon side of the canopy is avoided to prevent sunburn. VSP is compatible with both cane pruning and spur pruning and lends itself well to mechanical harvesting and hedging, giving it a significant practical advantage over less mechanizable systems.

• Shoot density in VSP should be managed to approximately three to five shoots per linear foot of trellis for optimal airflow
• Fruit zone leaf removal improves cluster light exposure and air circulation, but afternoon-side removal is avoided in hot climates to prevent sunburn
• Compatible with both cane pruning and spur pruning, offering flexibility across different grape varieties and sites
• Lends itself to mechanical hedging and harvesting, providing labor efficiency advantages during operations at scale

VSP installation is a significant capital investment, with costs running approximately $6,000 to $9,000 per acre for materials and labor. The system also requires ongoing labor for shoot thinning, shoot positioning, and canopy management through each growing season, making it more expensive to maintain than simpler trellis configurations. One clear limitation is yield: VSP limits production to less than 5 tons per acre, which suits premium winegrape programs but can make the system economically unviable for high-volume operations. In the context of climate change, researchers at UC Davis and California State University Fresno published a 2022 study in Frontiers in Plant Science suggesting that warming in regions like Napa Valley may be rendering VSP suboptimal, as its open cluster zone can lead to sunburn and yield loss during intense heat events. Growers increasingly weigh these trade-offs against alternative systems that offer more canopy shading.

• Installation costs approximately $6,000 to $9,000 per acre for materials and labor in quality wine grape regions
• VSP limits yields to less than 5 tons per acre, suiting premium production but not all commercial operations
• A 2022 peer-reviewed study found that VSP canopies in warming climates risk cluster overexposure, sunburn, and yield loss during heat events
• Reduced fungicide application needs due to improved airflow offer sustainability benefits, though high per-season labor remains a cost factor

VSP's global reach stems largely from its adaptability. The system was first codified and popularized in cool-climate Europe, but it was the pioneering canopy management work of Australian viticulturalist Dr. Richard Smart, who consulted for over 300 clients in approximately 40 countries throughout his career, that spread modern VSP principles worldwide. Smart's book 'Sunlight into Wine,' published in the early 1990s, became an internationally recognized reference on canopy management. Regional wire configurations differ to match local conditions: in California, the fruiting wire sits higher at 100 to 110 centimeters, while Piedmont uses a much lower 55 to 60 centimeters, and Champagne employs a wire as low as 20 to 30 centimeters. Growers in warmer climates have begun modifying VSP by adding crossarms to widen the canopy and provide additional shading, reducing direct sun exposure on clusters as temperatures rise.

• Dr. Richard Smart consulted for over 300 clients in approximately 40 countries, spreading modern canopy management and VSP principles globally
• His book 'Sunlight into Wine' is regarded internationally as a foundational reference on canopy management
• Fruiting wire heights vary considerably by region: California at 100-110 cm, Piedmont at 55-60 cm, and Champagne at 20-30 cm
• Modified VSP with crossarms is increasingly used in warm-climate regions to widen the canopy, provide cluster shade, and reduce heat-related damage