By: Gerald Dlubala
From pruning, shoot thinning and positioning, leaf and lateral care to hands-on vine training, canopy management is the best way for a vineyard to achieve optimal, mature fruit from their vines. Good canopy management, partnered with the proper trellis and row spacing, allows vineyards to better combat fruit loss due to disease or pest damage while providing an overall protective and nurturing environment.
Canopy Management Is An Evolving Science
“It’s always been evolving, but it seems to be moving along at a more deliberate pace now,” said Duff Bevill, founder and partner of Bevill Vineyard Management in Healdsburg, California. “We’ve come a long way in the past 30 years from when it was fashionable just to have the California flop, meaning the grapes were grown-up vertically, and the canopy was left to flop over. When increased production was needed, and European varieties were introduced, it became apparent that we needed to provide better light and greater air circulation for the fruit. Around the 1980s came the push to reduce or eliminate bunch rot and mold, and after a particularly wet season, the practice of leafing began. Then around the mid-1980s, Dr. Richard Smart, an Australian viticulturist, revolutionized our way of grape growing with his Smart-Dyson trellis system.”
Smart’s trellis system helps canopy management by finding the balance in leaving enough foliage to facilitate the necessary photosynthesis process without causing excessive shading that would negatively impact fruit ripening or promote disease.
“His style of trellis system is still the way to go,” said Bevill. “We see the Vertical Shoot Position trellis or modified VSP trellis with movable wires used the most because it traditionally results in a high-quality first crop. Another popular configuration is the high wire system, with the first wire 42 to 48 inches above the ground and then a secondary wire hanging about six inches above that first one. The downside to the high wire system is that it creates a need for manual shoot training for about the first five years. But if done properly, subsequent pruning can be done mechanically, with manual pruning only necessary for mechanical misses. Suckering is also minimal.”
Bevill told The Grapevine Magazine that hand labor can eat up to 60% of a vineyard’s expenses, so that is an area of canopy management that is drawing extra attention. In an industry looking toward a mechanized future but, in the meantime, still requires hand labor, the VSP trellis remains the best all-around canopy management trellis for fruit production.
“First, that hand labor has to be available,” said Bevill, “and it needs to be available when needed, frequently and for extended times to get the fruit picked on time and during prime harvest conditions. That’s getting harder to come by and more expensive to utilize. We offer bunkhouses and higher wages to our immigrant workers here on H2A visas to ensure our labor availability. But if things keep going the way they are, I would estimate that such extensive use of hand labor will end within the next five or six years in favor of mechanical labor. Compatible trellis design, along with smart canopy management, has a lot to do with this, allowing your trellis systems and vine configurations to grow in a manner that is favorable to mechanical picking, pruning and leafing. It’s better if you can accomplish these tasks with the off-the-shelf mechanical implements available today.”
Bevill has already seen this in action. By applying the principles of trellis placement and design with well-planned canopy management, the cabernet sauvignon vineyards have shown a dramatic decrease in farming costs associated with labor.
“Only one man is needed per ten acres here in Sonoma County,” said Bevill. “That figure matches what we believe is necessary, and that’s also what we have and use. Currently, only about 50% of farms are mechanically harvested. Many older ones can’t take advantage of mechanized farming because of how they were originally planned. Some leafing and mechanical harvesting can be done, but much of the canopy management has to be done by hand. Some older vineyards with their original planted vine systems are still entirely managed using hand labor. We are seeing a lot of these vineyards now being pulled out and replanted to use a flat-faced trellis system more conducive to mechanical farming.”
Bevill told The Grapevine Magazine that mechanized farming will likely be the focus for the foreseeable future. There is nothing new on the horizon regarding the mechanical aspect of agriculture. All the advancements are within farming technology, things like devices to better detect the best times and amounts for irrigation, and increased uses for drone mapping. The yields and performance of high wire trellises are showing promise, but it will be another 10 years before any data can be confidently identified as reliable.
“Overall, farming knowledge is constantly increasing, and as a vineyard management company, we are always looking at new and better planting standards and goals. They’re all tied into making mechanized farming as friendly as possible,” said Bevill. “Acquiring and using machinery to do the work is certainly the way of the future. It’s much cheaper and more reliable than hand labor, and let’s face it, it’s there when you need it.”
Seeing Each Vineyard As A Unique Environment
“I literally have a different protocol for every vineyard depending on the winemaker’s desires for his product and the environment that we’re growing in,” said Mike Loconto, viticulturist for Barbour Vineyards, a vineyard management and development company in Napa, California. “You know, we do all the normal tasks, like suckering, tucking, shoot positioning and hedging, but the winemaker’s end goal determines the amount and timing of these tasks and the best canopy management practices for their situation. For example, we like to leave 12, 14, or 16 leaves per shoot to get two clusters of fruit out of each one, but when to remove those leaves is different for each client. We always like to open up the fruit zone, including below the clusters, but you have to leave just enough shade to baffle the sunlight and produce a great environment all around the fruit zone. It’s about getting sunlight and airflow to that bloom at the right time to deter disease and increase the quality of the fruit.”
Loconto told The Grapevine Magazine that canopy management in Napa is all about controlling the heat and sun exposure to provide the highest quality fruit and the highest volume of product. When some of the older vineyards were installed, they preferred open, wide spacing between the rows. Over time, in an attempt to increase grape production, the vineyards started tightening up and leaving less and less spacing between the rows. Some were tightened to the point that they lost volume, quality, or both by inadvertently limiting light and decreasing airflow, increasing heat retention and inferior growing conditions.
“Heat prevention here in Napa is big and proven to directly affect quality, so now we try to stay around the seven-foot mark for row spacing and utilize cross arms to provide shade and heat prevention for the fruit,” said Loconto. “In any vineyard installation, you want to be smart about canopy management and factor in the ability to mechanize the farming now or in the future. Labor is so expensive that even if you can find it, you may not be able to afford the amount you’ll need to get the tasks done on time. Canopy size and row spacing need to be used jointly so that at some point, mechanized tools can be used for leafing, pruning and harvesting. By using between eight and 12-inch cross arms, you make more effective use of available mechanized tools.”
Loconto works mostly with high-end cabernet growers, and over the past five to 10 years, he’s seen the customary canopy management practices start to change.
“Call it climate change or whatever, but we’re starting to see a fundamental change,” said Loconto. “There’s still a high use of VSP or modified VSP trellis systems, but any newly planted, replaced or moved rows are being repositioned and spun in a better and more precise North-South orientation. This makes better use of the natural path of the sun and maximizes and better balances the use of morning and afternoon for both sides of the canopy. After that, it’s about timing and the goals of the vineyard regarding their fruit and vine quality and desired yield. If you have weak or younger vines, it may be better to sucker sooner and perform your fruit thinning. For stronger and older vines, you can thin fruit and sucker later for maximum sugar loading. Open zones are beneficial for more aromatic profiles, and they can help with the amount of acidity and tannin development with simple vine management. You always want warm days and good sap flow for pruning.”
Different environments require different management and trellis considerations. Vineyards located in volatile weather settings have to be willing to use netting, shades or some other blocking material in case of severe weather, extreme winds or hailstorms. Some colder climate vineyards make use of buried canes, green growing vines that are pulled down and buried in the vine row. The Geneva Double Curtain trellis is a popular choice for increased frost protection because of its downward growing, split canopy system. Still, being bulky and top-heavy, it is a liability in areas experiencing frequent windy situations.
“Our biggest challenge here in Napa is to develop mechanized vineyards that retain the quality we’re known for, while also controlling heat and sun exposure issues,” said Loconto. “Everywhere you go, you’ll see misters and shade cloth used to combat sun exposure. For those older vineyards that are still orientated to have unequal amounts of sun in the morning and afternoon, there is a noticeable difference on the contrasting sides of the vine. Any issues we address have to be solved with the idea of optimizing our vineyards for mechanical farming. Plain and simple, labor is just hard to come by and getting harder. Some equipment manufacturers are helping by developing machines that are comparable to hand labor, gently pulling the right amount of leaves while being relatively gentle on the fruit and soft on the clusters. That trend has to continue to move towards the mechanized vineyard.”
