Eric Stafne, Mississippi State University
Before you choose a trellis design, consider:
The type of grape to be grown will influence the most suitable type of trellis. American and most French-American hybrids do well on the High Cordon (HC), Umbrella Kniffen, or Geneva Double Curtain (GDC) systems. American and many interspecific hybrid grapes have a natural tendency for downward growth, making them well suited to these systems. European (Vitis vinifera) grapes are predisposed to upward growth. The Vertical Shoot Positioning (VSP) system is a good fit for vinifera type grapes. Vinifera grapes can be grown on a high cordon and likewise, American and hybrids on VSP, but they will require more training and extra management to ensure proper productivity.
Some sites may be unsuitable for certain types of trellis systems. Hilly or rolling terrain may be difficult to manage with complicated systems. Site soil type will also influence vine vigor, so adequate consideration should be given to evaluating potential vigor before planting.
Another factor to consider is the inherent vigor of cultivars and vigor imparted by the vineyard site. Vigorous sites or cultivars may benefit from divided canopy training systems. Divided canopy training systems can be vertically or horizontally divided. The Geneva Double Curtain is an example of a horizontally divided canopy and Scott Henry is an example of a vertically divided canopy. In a divided canopy system, each vine has more surface area to fill and thus has potential to produce more fruit. Additionally, canopy shading is reduced and fruit quality increased. Many popular American and hybrid wine grape cultivars are compatible with divided canopy training on high vigor sites.
Mechanical harvesting and pruning are other issues to consider. On small vineyards, most grapes will be hand pruned and harvested. On vineyards of more than 10 acres, mechanization should be considered. Even if the vineyard will start out with hand labor, a plan for possible mechanization in the future will be beneficial in the long term as the industry continues to grow and develop. HC, GDC, and VSP are all suited for mechanical harvesters. However, single curtain (undivided) canopies are generally better suited to mechanization than divided canopies.
Maintenance of grape trellis systems is a constant job. It probably won’t be extensive each year, with the exception of wire tightening. Other periodic maintenance activities may be fixing broken wires, tightening brace wires, repairing wind damaged posts, and evaluating posts for looseness, damage, rot, termites, and other problems. Use of high tensile wire can greatly reduce the need for re-tensioning of wires each year. New wire connecting devices have been developed to make trellis installation and maintenance much easier than in the past.
Trellis cost is a major component of starting a vineyard, so plan wisely. Some trellis systems have more components than others, making them more expensive to construct. Layout and row length also play a role in cost, as shorter rows result in more end post assemblies per vineyard area.
There are many different types of trellis systems, from simple types that are less expensive, to very complex systems that require a great deal more expense to construct. Choose a system that is appropriate for your cultivars and level of commitment. New growers should contact individuals who have constructed a trellis to learn how to do it properly and what mistakes to avoid.
Constructing a Vineyard Trellis, Iowa State University
Training Systems, Iowa State University
Reviewed by Bruce Bordelon, Purdue University
and Jim Wolpert, UC Davis