Post-Harvest Vineyard Maintenance: Tips to Finish the Year Off Right

By: Alyssa L. Ochs

Although the busy time of harvesting grapes is winding down or has ended for many vineyards, there’s not much time to sit back and relax before more critical work must be done. Many post-harvest vineyard tasks should be on every vineyard’s to-do lists to prepare for next year’s crop and sustain the longevity of the vineyard’s operations.

The Basics of Post-Harvest Vineyard Management

  After the growing season ends and the grapes have been picked, grapevines go dormant and signal that it’s time to start preparing for next year. Some of the vital maintenance tasks to do after harvesting are removing bird netting, analyzing the soil with samples, repairing or replacing trellising and equipment, and planting a cover crop to reduce soil nutrient loss and control erosion. It is also the time of year to be proactive about pest control, consider irrigation strategy, stock up on new vines and put some thought into overall vineyard management strategy.

  As vineyards wrap up harvest operations and prepare for winter, some specialists may be helpful for advice, products and services.

•    Vineyard management companies

•    Pest control companies

•    Irrigation consultants

•    Nurseries

•    Trellising companies

•    Soil companies

Check and Repair Trellising

  Trellising is a big part of post-harvest maintenance, because, in most climates, grapevines need supports to secure the wood and summer shoots within the training system, and ensure proper ventilation and exposure.

  “Furthermore, the trellis helps to improve the implementation of viticulture work and facilitate mechanized procedures, like machine harvesting,” said Oliver Asberger, Vice President of PA Trellising Systems in Charlottesville, Virginia. “If a trellis is not designed right or maintenance is not kept up, it will lead to deficiencies in vineyard performance and higher costs in labor and parts.”

  Asberger told The Grapevine Magazine that two primary signs of a good trellis are tight wires and stable posts. “Each growing season, the trellis experiences pressure on its systems, and that leads to loosening of parts or even breakage,” he said. “To optimize the performance and keep costs down, the trellis is best fixed when the pressure is off and the vine is dormant.”

  PA Trellising Systems is a distribution company, rather than a vineyard management company, but it can offer advice on how to modify and repair existing materials if a vineyard notices a problem with its trellising system.

  “When it comes to new establishments, we guide the buyer to what options are available and optimal for post models, forms of galvanization, size and length, inside or outside hooks, set depth and use of accessories, like cross-arms or wire extenders,” Asberger said. “Also, we are able to customize our posts to offer the best solutions for a unique growing situation.”

  Another company that provides trellising products is Gripple, which offers the Gripple Plus for simple push-fit splicing, locking and tensioning system that is up to five times faster to install than traditional methods for broken trellis wires. Gripple joiners and tensioners have patented ceramic rollers that deliver a better grip and non-corrosive hold on the high tensile wires that are used in vineyards today. They can be used in conjunction with the Gripple Torq Tool or Gripple Contractor Tool to return tension to slacked or broken trellis wires quickly.

  “The Gripple Plus range is perfect for ongoing maintenance and allows for re-tensioning year after year,” said Erik Shortenhaus, Gripple’s Business Development Manager. “Gripple also provides pre-made cable bracing kits designed for the quick and easy repair of end post assemblies. Within our end post cable bracing kits, we offer a range of clips and end-fittings that are designed to quickly and securely attach to any end post material on the market, such as wood, drill pipe and channel steel. Additionally, Gripple offers a range of below-ground, percussion-style anchors that can be instantly load-locked and serve as a dead man anchor point or additional reinforcement for existing anchors. Gripple products make vineyard installation, maintenance and repairs simple and secure.”

  Shortenhaus pointed out that the growing season, crop load, weather, farming practices and harvest activities all contribute to possible wear on a vineyard’s trellis system. He said that the rigors of harvest, especially machine harvest, take a strenuous toll on a vineyard’s trellis structure, making this a prime time to check trellising.

  “Taking account of any damage that has occurred during harvest or over the year, and addressing it prior to next year’s crop, is essential to providing a solid, consistent and hassle-free foundation for your vines,” said Shortenhaus.

Check and Improve Irrigation

  Vineyard managers should remember to check their irrigation systems after harvest since machine harvesting can be rough on the vines and system. Look for physical damage, such as fallen hoses or emitters.

  Brett Curtis and James Bengtson of California’s Bennett Water Systems recommend using the post-harvest time as an “alarm clock” to handle yearly maintenance and “do an eyes-on evaluation with a full system flush and a line treatment to clean the emitters.”

  At the filter station, they recommend inspecting the sand for the sand media filter, working condition of the backwash valves and screen of the screen filter. Other recommendations are to check the pressure gauges to assess the accuracy of the pressure differential and to look for gasket leaks and other visible signs of failure.

  “Post-harvest irrigation is what lets you double-check that all of your fixes were successful before you put the system to sleep for the year,” said Curtis and Bengtson.

  Bennett Water Systems has knowledgeable key-account managers, salesmen and project managers who can perform evaluations, get to the root of the problem, and perform any fix that is required.

  “We have crews with years of experience both in installing drip systems for vineyards and performing repairs and regular maintenance,” said Curtis and Bengtson. “Whether it’s an issue with a pump, filter station or anything downstream of the filter, like pipe, tubing or emitter issues, we have a way to fix it or a solution to prevent it from causing issues in the future.”

Soil Enhancement and Maintenance

  One of the essential tasks to do post-harvest is evaluating the soil for determining nutrient and organic matter needs.

  “The vines utilize nutrients during the growing season, but not all nutrients are absorbed at the same rate,” said Coult Dennis of Superior Soil Supplements in Hanford, California. “The pH level of the soil makes a big difference in the availability of nutrients to the vines. Some nutrients are more readily available at lower pH; others are more available at higher pH. It’s important to look at the pH levels of both the soil and the irrigation water sources in order the make the best possible decisions regarding soil amendments.”

  Founded in 1983, Superior Soil Supplements dedicates themselves to building healthy soil and being California’s largest distributor of bulk agricultural soil amendments and landscape materials. It has facilities in Ivanhoe, El Nido, McFarland, Hanford and Coalinga and believes that balanced soil builds a strong foundation for crops, saving the farmer money on fertilizers and other crop inputs in the future.

  “Making sure your vines are set up for optimal growth in the spring is vital to having flourishing canes and ultimately, a strong and profitable yield,” Dennis said.

Order New Vine Stock if Needed

  After harvest is the ideal time to determine whether the vineyard will need new vine stock for the next growing season.

  “If you are looking to order vines for the spring of 2020, the best time to order vines is from August to December 2019 to ensure that varieties you want are still available,” said Ray Winter of Winterhaven Vineyard and Nursery in Janesville, Minnesota.

  Established in 2001, a year after starting a vineyard of over 14 acres and 6,000 vines, Winterhaven nursery specializes in cold-hardy wine grapes and sells many bare-root grapevines for red, white and table grape varieties. Winter said that the most important things for a vineyard to consider when ordering vines from a nursery should be whether the varietal is hardy to the growing location and if there is a market for them if the vineyard does not plan to use them in their wine.

Final Words of Advice

  In addition to these post-harvest maintenance tasks, vineyards will also want to spend time identifying and removing diseased vines, perhaps with the guidance of a local pest control company that specializes in vineyard pests. It’s also time to check vineyard equipment for routine maintenance or repair needs, as well as to identify which pieces of equipment to replace.

  Take time to reflect on the season and discuss with staff what went well and how to make improvements for the year ahead.

In closing, here are a few final words of advice from our industry experts to guide vineyards across the country through the post-harvest time of year and ensure a successful 2020 season.

For trellis maintenance, Oliver Asberger of PA Trellising Systems advises vineyards to establish a trellis that will last for the lifetime of the vineyard—approximately 25 years— and is mostly maintenance-free.

  “Too often, at the time of establishment, growers choose materials at lower costs or cut corners within the stability performance but later end up with extremely high maintenance and replacement costs,” Asberger said. “Also, in this era of less labor and more mechanization, a grower should consider if the system is set up to use technology in the future, even if the vineyard doesn’t currently own it. A later modification will be costly or not applicable at all.”

  Asberger also said that a trellis is best maintained during the dormant time because, with no canopy present, it’s easy to see loose or missing parts and replace them more cost-effectively.

“Doing this work when the canopy is present will hinder the effectiveness and most definitely will lead to damaging the shoots,” he said.

  Shortenhaus of Gripple also advises vineyards to take a visual inventory of their trellis systems and make any needed repairs or adjustments to give the vineyard a strong foundation for the next growing season.

  “Using Gripple for your trellising repair and maintenance needs couldn’t be simpler or more reliable, and it will effectively reduce your work time,” he said.

  Bennett Water Systems’ most significant piece of advice for irrigation is to remember that the system installed impacts yield directly.

  “The efficiencies of the system all play into it, such as pump efficiency, pressure losses, if supplements are going where you expect and need them and if your water is being evenly distributed throughout the whole field,” said Curtis and Bengtson. “For Bennett Water Systems, it is our goal to design and install a system with the highest distribution uniformity as possible that provides our customers with the tools that they need to produce maximum yields most sustainably.”

  Dennis of Superior Soil Supplements said that the thing his company sees most in California is a lack of organic matter in the soil. He said that organic matter should make up about 5% of soil composition and while this is difficult to achieve, adding any amount of organic matter will help. Organic matter helps retain moisture and nutrients in the soil, promotes beneficial soil flora growth to chelate nutrients, and breaks them down into a structure that can be used by the plant.

  “Compost is the least expensive and easiest way to build up organic matter,” Dennis said. “Compost can be derived from municipal green waste sources, as well as from manure and even processed sewage. Green waste is the most popular choice for vineyard applications. Like any other crop input, organic matter is depleted in the soil through the growing season and needs to be replenished.”

  Dennis recommends compost application as part of a grower’s yearly soil fertility program. “To maximize spreading efficiency, we often blend fertilizers, sulfur, limestone or dolomite with the compost, so the year’s soil needs are addressed with one pass of the spreader,” he said.

  Concerning ordering vines, Winter of Winterhaven Vineyard and Nursery said vines coming from a cold climate nursery tend to grow better than those purchased from warm climate nurseries, even though the genetics are the same.

  “We have had many customers tell us this,” Winter said. “After the fruit comes off our grapevines, we always try to do a fertilizer spray on the leaves to feed the vine and get them ready for the winter.”

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