February 15, 2014 | by Brent Young

Pruning grapevines during their winter dormancy period remains the most expensive type of vineyard work we do each year. The practice is tedious and downright tiring with a lot of repetitive motion—it is both an art and a science, as described in our last pruning video. The Jordan viticulture team of four usually spends about three months (nine hours a day, six days a week) pruning Jordan’s 112 acres of estate vineyard acres. That’s about 200 vines per hour, 1,800 vines per day or 1.85 acres completed per day.

Grapevine Pruning Techniques: Double-Pruning with a Pre-Pruner Machine

While essential to growing a balanced grapevine each vintage, this laborious process is a leading cause for employee injuries—often straining shoulder, hand or back muscles. Keeping our employees healthy is just as important as keeping the plants healthy, so we are experimenting with a new double-pruning technique using a machine called the Visio pre-pruner, as demonstrated in the above video. The machine pruner handles the first, most physical part of the cutting, then our team will follow and hand prune the grapevine into a two-bud spur—the most critical step in the pruning process.

grapevine pruning, machine pre-pruner on tractor, Jordan Winery
A pre-pruner attached to a tractor at Jordan Winery.

Machine pruning has been around since the 1980s but only recently started gaining mainstream acceptance in California wine country—not only because of employee safety benefits, but also because the technology has made huge strides in efficiency and precision. Now, machine pruners have automated sensors that open and close their jaws around the metal stakes in the vineyard row and end posts. The pruners’ blades can comb through the vineyard’s canopy and slice off the wood without cutting the delicate trellis wires. It’s a very clean, meticulous piece of equipment that allows us to maintain quality of our viticultural practices while keeping our staff healthy.

The cost of an employee getting injured far exceeds the cost of this piece of equipment, but the savings don’t end there. The pre-pruner machine attaches to a standard tractor and is 15-20% faster than conventional pruning by hand. We expect at 90% decrease in the possibility of pruning-related injuries to our employees as a result. It will pay for itself within five years.

grapevine pruning, Jordan Winery
A Jordan employee hand-prunes a petit verdot grapevine after pre-pruning with the machine.

Machine grapevine pruning also offers a health benefit to the plant, combating against the fungus eutypa, which enters the grapevine through the open-cut wounds associated with pruning. Vines are most susceptible to eutypa when it’s wet and rainy, which is typical weather during the winter pruning season. Normally, we start pruning by the first week in December and don’t finish until March, but the Visio pre-pruner allows us to being pruning in mid-January and be finished by March.