By: Alysa L. Ochs
Although the busy days of harvest are now behind us, there isn’t much time for vineyard staff to sit back, relax and enjoy the fruits of their labor. Now begins the important task of pruning, and winter is the ideal time to separate healthy wood from the dead and damaged. Whether you’ve just started vineyard operations or have been running a vineyard for decades, it never hurts to be reminded of the best dormant pruning practices and learn about emerging technology to make this vineyard task easier.
The Purpose of Pruning
Dormant pruning is critical to grape growing because it maintains the training system, allows operators to select fruiting wood, and manipulates the quality of fruit produced. It helps maintain vine form, regulates the position and number of shoots on a vine, improves fruit quality, stabilizes production and improves bud fruitfulness through careful bud placement and selection. Pruning is also an opportunity to get control over weeds, identify vine diseases and address pest concerns before they become significant issues.
When to Prune
As a general rule, dormant pruning can be done anytime between leaf drop in the fall and bud break in the spring. Vineyards around the country may start pruning right after Thanksgiving into mid-December, but this tedious job usually extends through March. Some vineyards wait until January to begin their dormant pruning because this is when the canes become woody.
Jordan Lonborg, viticulturist at Tablas Creek Vineyard in Paso Robles, California, told The Grapevine Magazine that his vineyard chooses when to prune largely based on weather.
“We typically start pruning in January,” he said. “But the majority of pruning takes place in February and March.”
Vineyards may postpone pruning to assess cold injury better and adjust pruning levels to compensate for losses. Double pruning is sometimes used to avoid spring frost injury. However, the availability of labor in the winter months has a big impact on when vineyards do their pruning as well.
“Pruning your grapes too early in the season is a mistake that novices make that can result in no fruit production,” Randy Killion, president of Zenport Industries in Sherwood, Oregon told The Grapevine Magazine. Zenport manufactures and markets professional and consumer specialty horticulture tools and supplies for the lawn and garden, landscape, irrigation and agriculture markets.
“If low temperatures and strong winds follow pruning, it’s very possible that the pruned parts will freeze,” Killion said. “This will make you lose all or part of your crop. Therefore, it’s recommended that pruning is delayed until February.”
Types of Pruning
Cane pruning is most commonly used for grape varieties that have low natural fruitfulness on the basal buds. This type of pruning requires vineyards to replace the one-year-old canes annually.
Spur pruning is most often used for high fruitfulness varieties and is relatively easy to do. This is the most popular method of pruning among vineyards today, particularly for grape varieties like Merlot and Cabernet Sauvignon.
Meanwhile, head training is sometimes practiced by vineyards without trellising. While this practice is economical, it’s important to watch for rot and mildew, as well as congested canopies that can topple under their own weight.
“We spur prune the majority of the vineyard because 65% of the vineyard is on trellis,” said Lonborg. “Ten percent of the vineyard is cane pruned as well. A majority of the cane pruning occurs on Syrah and Viognier due to their vigorous nature.”
Disease Identification and Weeding While Pruning
Grapevine diseases can occur at any time of the year, but the winter season is a useful time to check plants for abnormalities and take action. Some of the most common diseases that grapevines experience are Pierce’s disease, phylloxera, downy mildew, powdery mildew, gray mold, black rot and vine truck diseases such as Petri disease and black measles.
While pruning, keep an eye out for discolored lesions that are red, brown or black. Other signs of disease are curling leaves, weak or short shoots, rapid wilting and shriveled leaves or grape clusters. Also, look for grapes covered in a gray or tan powder or leaves with yellow edges.
However, a visual diagnosis may not be sufficient, and it may require laboratory analysis to identify certain bacterial and fungal diseases correctly. To protect the healthy plants in the vineyard, promptly remove diseased wood and either burn it (if your area allows burning) or add it to the green waste bin to be hauled away.
Pruning and weeding go hand-in-hand around this time of year, and there are important factors to consider when developing a vineyard weed control program for the dormant months. Nicola Rinieri of Rinieri S.R.L. in Forlì, Italy, told The Grapevine Magazine that customers must think about the conditions and their most common practices. For example, vineyards in the Northeast hill up the soil to protect the vines, which requires specialized equipment. Rinieri provides agricultural machinery for vineyard processing, pruning machines, offset machines, in-and-out rotary tillers and cultivators.
Pruning Tools and Supplies
While the process of pruning may seem simple enough, some specific tools and supplies help get the job done right in the most efficient way possible. The most basic hand tools needed for pruning are a few good pairs of pruning shears, loppers and saws. Vineyards also use hand-held scales to measure pruning weights and ribbons, garden tape or cloth strips to identify fruiting canes and renewal spurs.
There are pros and cons to both manual and mechanical pruning, and decisions in this regard are often the result of long-standing vineyard traditions.
“All of our vineyard is manually pruned,” said Lonborg. “Maintaining the proper structure of the vine is of the utmost importance when producing high-quality fruit.”
Rinieri said a common mistake that vineyards make when doing mechanical pre-pruning is trying to use a machine to do a job where it’s not appropriate in the vineyard.
“It is common to have the wires not tighten enough so the machine can catch them or to have a cross arm so wide that the machine cannot open enough to avoid them,” she said. “This was happening many times in the past, but fortunately not as often lately.”
Amanda Van Hoorn, operations manager for INFACO USA in Livermore, California, told The Grapevine Magazine that the F3015 Electrocoup pruning shear with a patented safety system is popular among vineyards for pruning purposes. The history of INFACO dates back to 1984 when M. Daniel Delmas invented the world’s first electric shears. Today, INFACO offers a versatile and compatible product line that also includes an electrical tying device, electric olive harvester and battery-powered tools.
“No other company offers the safety and versatility of the F3015 Electrocoup shear,” Van Hoorn said. “Specifically, we offer a patented safety system that ensures workers won’t injure their non-pruning hands. Users can also increase cutting capacity by just changing the head on the shear. This means that vineyard managers can use the same tool for cane pruning, converting vineyards and cutting out Eutypa. The shear’s battery is also compatible with a variety of other INFACO tools for vineyards, including an electric tie gun and suckering tool.”
Killion of Zenport Industries told The Grapevine Magazine about the wide selection of quality hand pruners, loppers and saws that Zenport offers, as well as the company’s series of battery-powered pruners. Popular Zenport products are the Zenport EP108 CORDLESS ePruner, a 0.5-inch cut battery-powered electric pruner, and the Zenport EP2-778 ePruner, a 1.25-inch cut battery-powered electric pruner.
“These two pruners are immensely popular for vineyard use because of reduced fatigue upon workers, dramatically increasing pruning efficiency and speed,” Killion said. “Both pruners enable the user to prune for an entire day.”
Meanwhile, Rinieri offers two types of machines for pruning, called CPL, and each type has four different sizes based on cutting length. “It is important to find out if a vineyard is cordon or guyot and then decide which length the customer needs,” Rinieri said.
Rinieri also sells many weeding tools, including Bio-Dynamic, TURBO with hoeing blade, plow kit and Bio-Dynamic tools, and TURBO EVO with power harrow, disc hoeing units, mini shredder plus the blade and plow. These units are available with single or double side blades. Other offerings are the EL power harrow single-side, FS tiller single-side, and EP heavy-duty power harrow – all PTO driven.
FELCO can also be counted on to help vineyards prepare for the winter season, and it has been producing high-quality pruning tools for 75 years. FELCO’s Ryan Amberg told The Grapevine Magazine about their newest tool, the FELCO 822, launched just this year.
“It maintains its predecessor’s position as the most powerful electronic pruner on the market with new features, such as HSS XPRO blades for increased longevity, smaller multi-position power pack for ergonomics, and the first-of-its-kind connectivity for future vineyard management applications,” Amberg said. “If you are looking for a solution to carpal tunnel or a solution to a lack of labor, the FELCOtronic can be a real solution this winter.”
Pruning Considerations and Tips
Proper pruning practices come with time and wisdom collected over many winter seasons. Being prepared and having a plan in place for dormant pruning is always a good idea, but it is also necessary to be flexible in case weather, the labor supply, or other factors throw a wrench in your plans.
Van Hoorn of INFACO USA said that labor is a huge factor when planning for pruning and buying new pruning tools.
“The labor crisis is here to stay, and with it comes increased prices for every operation in the vineyard,” she said. “Proper pruning is crucial to producing great grapes but is one of the most labor-intensive tasks on the vineyard. The F3015 pruning shear from INFACO has shown an average productivity increase for vineyards of 30% and also increases the number of years workers can continue pruning. Powered pruners have an inherent risk, though, and that’s why the F3015 pruning shear features a patented safety system to protect workers’ non-pruning hands. There is no doubt that this is becoming a must-have tool for vineyard managers who need to find ways to use less labor and keep their best workers.”
Van Hoorn said vineyards should, “Switch to an electric shear before the labor market chews you up and spits you out!”
Killion of Zenport reminded vineyard managers that pruning tools are used extensively, and battery-powered pruners, in particular, need to be serviced periodically.
“Choose a manufacturer that stocks replacement parts, like blades and bumpers,” Killion said. “For electric pruners, it is imperative that a service center with quick turnaround is available.”
Killion also said it is crucial to identify last year’s growth because this is where the coming season’s fruit will form.
“The wood where the fruit is produced on the last year’s growth will have a different color than the older wood that can’t produce fruit,” Killion said. “You will usually be able to identify the last year’s wood because of its reddish color.”
Rinieri of Rinieri S.R.L. said that the main factors to consider are the size of the vineyard and row width.
“When a vineyard is large in size, it needs a quick machine, like Bio-Dynamic, TURBO or TURBO EVO,” she said. “If it is small, it can use EL, FS or EP. Also, finding out what type of work a vineyard wants to do is important because some machines can use different working heads, like TURBO EVO and TURBO, with no power tools. The width of the row is important because all machines have a range of widths in which they can work.”
Amberg of FELCO said that three things should come to mind when purchasing new tools: the application of the product, the longevity of the product, and the ability to maintain the product. Product application is vital for improving vineyard ergonomics, which is why FELCO offers so many different hand pruner models.
“We believe ergonomics are key in a high-stress pruning environment like the vineyard,” Amberg said. “A tool should be bought, taking into consideration hand size, left or right-handedness and average cut diameter. We make tools for all varieties of these combinations.”
Regarding longevity, Amberg said hand tools are the workhorse of a vineyard crew’s arsenal during pruning season, which means they are put under a lot of stress and abuse.
“This is why we protect our tools with military-grade aluminum handles, as well as our precise manufacturing process that allows these tools to tolerate the stress of intensive pruning without issue,” he said. “Look for tools that are built to last and that you will not replace multiple times in a season.”
Amberg also pointed to proper maintenance as a way to get more life out of your tools and extend your return on investment.
“We build our tools so that with just simple blade and spring changes, you can maintain your tool for a lifetime,” Amberg said. “This means on any aluminum-handled FELCO, all parts can be changed and replaced with ease, thanks to our precision machining. We produce our tools out of an old watch factory in Switzerland, giving us the ability to put tools back together hundreds of times without any give in the mechanics.”
However, it doesn’t matter what tool you use if you start too early, said Longborg of Tablas Creek. “If you have the ability to wait as long as possible, do so!” he said. “If you can wait to prune until the vines start bleeding, you greatly reduce the risk of Eutypa infection.”
