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The height of the cordon or support wire will depend on your training system. A single-wire training system with a downward hanging canopy is the most common training system for table grapes in Oregon. With this training system, a good wire height is around 5-6 feet off the ground, allowing adequate space for the green shoots to grow before hitting the ground. I've attached a diagram of the single-wire downward hanging canopy system from the OSU Extension publication Growing Table Grapes. This guide will be very helpful for a variety of table grape topics, including training and pruning.

The next most common training method is a vertically shoot positioned (VSP) system. This training system is commonly used in commercial wine grape vineyards and can help improve color in red-fruited grape varieties. For this system, a support wire is usually around 3 feet off the ground with additional sets of catch wires above to keep the shoots vertical. This system requires more hardware and would not be recommended for very vigorous vines, but can create an attractive hedgerow with the right maintenance. You can find more information on VSP in the Growing Table Grapes guide.

If you have any other questions, grape-related or other, please do not hesitate to reach out to Ask Extension.

Cody Copp, Extension Horticulturist, Oregon State University