Yield versus Quality, Part 10

Mondavi: Close Spacing on Oakville Soils

Some say that it is in the poor soils of Bordeaux and Burgundy where these highest density vineyards make sense because the vines will never get big. But this is contradicted by Robert Mondavi’s apparent success with close spacing on Oakville’s considerably richer soils. With closely spaced vineyards for all Bordeaux varieties, Pinot Noir, Chardonnay and Sauvignon Blanc, few wineries have made the commitment to close spacing that Mondavi has. “The concept of a low vigor vine is the key,” Bledsoe says. He explains the conditions needed to achieve a low vigor vine, “a well-drained soil so water is not too available, not overly nutritious so growth is limited, combined with the proper combination of rootstock, spacing and grape variety.” Mondavi started doing research on rootstocks back in the early 80’s, long before phylloxera. “We were evaluating some of the newer rootstocks compared to the older ones planted more commonly around California. The older rootstocks (A x R#1) were selected for their viticultural performance, that is high vigor, high yielding, drought tolerant and easy to grow. They produced big, strong vines that you could plant far apart (8' x 12') and would fill up those spaces between the vines and the vineyard was fully productive in its fifth year. But when we looked at it from a wine quality standpoint we found a pretty strong correlation—in particular for the red varieties—between lower vigor rootstocks producing smaller vines and wines that were more intense, deeply colored with more emphasis on fruit flavors rather than vegetal flavors.”

Based on the concept that a smaller vine makes better wine, Mondavi began to replant using these low vigor rootstocks. Bledsoe recalls, “A side effect of the smaller vine is that you get less yield per vine, less brush and fewer leaves. Because of this diminished capacity for growth, using the old 8' x 12' spacing with a bilateral cordon, the cordon arms were not be able to fill the spaces between vines. But, they made better wine. So we increased the vine density to make up for this difference.” Although rootstock was the starting point, Bledsoe maintains that it is merely a building block, “vigor management is the foundation, rootstock and spacing are components.”

Bledsoe adds that the next critical component is irrigation or more accurately, soil moisture management, “With increased vine density, root density is going up—effectively every square inch of the soil is mined by roots. Once the vines deplete the soil moisture supplied during the winter, they slow down on their own and run into a deficit. They experience stress earlier in the season than a wider spacing regime would. This stress turns the switch from growing vegetatively to ripening the fruit—producing sugar, phenolic and aroma compounds that make up quality. Once you reach deficit, you manage that degree of deficit by supplemental irrigation so that the vine doesn’t totally collapse or decline. A lesser vineyard in which the vine roots continue to see ample water conditions keeps growing and growing requiring more canopy management. Cover crops are used, but why plant a cover crop to use up the water—we don’t make wine out of a cover crop. We put in an extra row of vines to induce that early season water deficit.”

Some feel that by adopting traditional French plantation densities to Oakville soils, Mondavi is violating fundamental viticultural practice to establish a marketing niche. Dokoozlian comments, “The concept of how you space a vineyard is based on anticipated vine vigor. The French plant their vineyards 1m x 1m because their vigor is so low; they have to plant at a high density in order to have an economic yield.” The implication is that what Mondavi is doing is artificial, because they are not basing plant density on the vigor of the site, but on a marketing concept. By using less irrigation and low vigor rootstocks, they are fine-tuning their system to make it fit their line of thinking. Dokoozlian adds, “Mondavi is putting their money where their mouth is. I totally respect them, they are doing something they think is right. I may not agree with the concept but I admire their commitment.”

Prats reacts to Mondavi’s high density approach: “I am convinced that 1m x 1m in California is not appropriate, that is my feeling. It is not right because the soil is far too rich and the vigor of the vine is too big and with such a high density there is a problem with shadow – of one row shading the neighboring row. The density has to be adjusted to the local conditions.” As for adopting French techniques he advises, “What you should understand is not the French technique but the French philosophy, which is to find the techniques which are appropriate to each individual location. The density in the Medoc is higher than it is in Pomerol for example, because the soils are different. The spacing is much wider in Chateauneuf du Pape because it is much drier than the Medoc. Each technique has been developed after the characteristics of the local area—the same has to be done in California.”

Bledsoe concludes, “Most people are not doing as tight spacing as we are, they don’t have the data nor do they believe in denser planting. We are not shying away from close plantings. We try to get about 6 tons/acre (85h/h)—and they produce reserve quality wines. If the definition of overcropping is delayed maturity, these are obviously not overcropped because our closest spaced vineyards are the first to ripen in their respective area.”

Former Etude Winemaker, Tony Soter has reservations about close spacing: “Close spacing in California almost always results in excess cropping for quality wine results; thinning becomes mandatory. This is less an issue in ‘marginal’ climates like Oregon and Northern Europe where fruitfulness is usually much lower.” Soter continues, “Close spacing is an answer to limited fruitfulness but comes with its own set of problems: (1) a higher probability of mildew and other rots (due to dense canopies limiting air circulation), (2) fruit closer to the ground rots more easily and also bakes in a heat wave and (3) requires vertical shoot positioning which crowds leaves and over-exposes fruit.”

A proponent of wider spacing is Dr. Richard Smart, international viticulture guru. To contend with a high vigor site such as Mondavi’s Oakville vineyards, he would not increase vine density to reduce vigor. He recommends reducing vine density in order to give more space to allow the vines to spread out or express their vigor. These larger vines inevitably require a more elaborate trellis system to efficiently array the foliage and grape clusters to intercept sunlight and maximize air circulation. Bledsoe disagrees, saying, “I think that is appropriate when the goal is 8-10 tons/acre and to keep the price of your wine low to be more successful on the world market. That is not what we are trying to do with our close-spaced vineyards in Napa. We are trying to make wines that compete with the top wines of the world and we do want to put limits on the expression of vigor. Because by concentrating the energy of the vine you do get a concentration of flavors.”

Generalizations are difficult without looking at a specific site. Dave Lattin, former Assistant Winemaker at Acacia Winery, now producing CL Wines, discusses the retrofitting of the Marina vineyard to wider spacing and a divided canopy. “We had vigor to contend with as a result of the high nutrient soil and vigorous rootstock (St. Georges). Carneros’ rolling hills have shallow soils (1m deep) which are full of clay on top of a clay hardpan. With Spring rains, the greater water holding capacity made the soil stay wetter, longer, compounding the high vigor.” Lattin remarked on the results, “Better flavors, better color, earlier ripening, decreased vegetal character and increased yields. It was a success and for certain sites I think it is appropriate.” But for strictly economic reasons, closer spacing is winning adherents. With the tight market for grapes, growers know that a higher vine density will produce a crop in the second or third year versus the 6–8 years for the wider spacings take to reach full production (particularly with a quadrilateral system). As for wine quality, no one is certain which one is going to make a better wine.