When establishing a vineyard, it’s nearly impossible to make a standalone decision. Every element, from the climate to the tractor, is part of a connected system. So when it comes to vine density—that is, how closely spaced vines are from one another—the ideal choice will largely depend on a suite of other factors.
At Chateau Montelena in Napa Valley, winemaker Matt Crafton has been working on two major replanting efforts over the past several years. In planning for these projects, every aspect of the vineyard and its management has been carefully considered in order to determine the ideal vine density. “It’s understanding the soil, understanding the climate, the right rootstock, right variety, right clone, right training method, right row orientation—all those things have to line up like a slot machine,” explains Crafton.
While it can be difficult to detangle a single element of a vineyard from the larger web, researchers and winemakers nonetheless have strong—and often contradictory—opinions on the best approach to vine density. Here, experts discuss the key ways in which vine density impacts wine quality and vineyard management in different regions around the world.
Understanding vine density
Vine density, or planting density, is usually expressed as the number of vines per hectare or acre. Density is impacted by both between-vine spacing within a single row of vines, and between-row spacing within a given vineyard.
Vine densities can range from hundreds to over 10,000 vines per hectare. The chosen density will be influenced by a range of environmental and socioeconomic factors and, in turn, the density will impact the style, quality, and price of the final wine.
Therefore, decisions on vine density will likely start by determining the type of wine a business aims to produce. “Your business goals should drive the decision-making,” says Stewart Spencer, the winemaker for St. Amant WInery in Lodi, California, and the executive director of the Lodi Winegrape Commission. “Who is your customer? Or is it being developed for yourself?” These types of questions will help determine the quality and price of the final product, and how the winemaking operation will be financed and managed.
How vine density impacts wine quality
Most winemakers aim to produce the highest quality wine possible for a given price. Therefore, most winemakers will choose a density that optimizes for quality. So, how exactly does vine density impact wine quality? Researchers and winemakers have tried to answer this question, though the results are not clear-cut.
A common line of thinking states that high-density plantings increase grape quality by increasing competition among vines, which in turn decreases yield due to more limited access to resources. With fewer and smaller grapes being produced by each vine—creating a more favorable skin-to-juice ratio—the quality of each grape increases, resulting in better wine. But digging into the data reveals a more complex reality.
“A lot of this [thinking that] high density equals high quality is coming from unirrigated vineyards, and a lot of those vineyards are now reevaluating that idea,” says Mark Krasnow, Ph.D., a consultant and the owner of Thoughtful Viticulture in New Zealand. “The point of bringing them close together is to induce competition, but in a dry-farm situation or in poor soils, you can over-stress your vines and then you get poor growth.”
A study on an unirrigated Pinot Noir vineyard in South Africa, for example, found that the more densely planted vines benefited early in the season from less vigorous canopies, which allowed for greater sunlight penetration, but as competition for water increased later in the season, less dense spacing was more favorable for the vines.
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