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W i n e s & V i n e s M A R C H 2 0 1 4 35 G R A P E G R O W I N G Noir. Obviously, these smaller crops also become uneconomical to farm after a while. If your farming costs approach $6,000 to $9,000 per acre, at less than a ton per acre you won't be able to stay in business for long. Even if you own a winery and are able to sell those bottles for $100, after you add in land costs, cost of farming before you get a crop, depreciation, etc., this yield model just does not make financial sense. In my humble opinion, having a balanced vine usually provides you with the chance to craft a balanced wine and still pay the bills along the way. W&V: How does canopy management fig- ure into the cropping decisions? Cabral: Canopy management plays a big part in determining how much crop we may attempt to mature. The first decision is what type of pruning system I am going to use. Bilateral cordon, cane or head training are probably the three most common here in the North Coast. If I choose to use a bilateral cordon, vertically shoot positioned system, I then need to determine how many spurs per vine will be needed and ulti- mately how many shoots per spur. Typi- cally on my 5 by 7 spaced VSP systems, I try to space out nine to 10 spurs and leave two shoots per spur. The height of the cor- don arms will also determine if you might need to hedge during the growing season. The goal is to not have to hedge during a typical growing season, but all of this depends greatly on the soil, vigor of the rootstock, irrigation habits and the weather during any particular growing season. The overall idea is to mature a crop with the least amount of canopy to ensure adequate phenolic and flavor ripeness without excess buildup of carbohydrates. I typically shoot- thin down to two shoots per spur, pull lat- eral shoots around the clusters on the morning sun side, and sometimes hedge to help slow down the buildup of carbohy- drates or sugars. This usually requires that we make several passes throughout the growing season, as each vineyard, block and clone responds differently. W&V: How do clone and rootstock affect your decisions about planting density and crop load? Cabral: Rootstock and clonal decisions are a big part of determining how densely to plant a potential site and then balance a crop. On weaker soils, I tend to use less- vigorous rootstocks and plant more densely. I try to then choose scion wood or clones that work well in that climate as well as with that rootstock. Row spacing is usually determined by the slopes or our ability to farm it safely. I widen up the row spacing as the slopes become more difficult, so that we can still get tractors, sprayers and harvest bin trail- ers into the vine- yard. Typical spacing for our equipment is 5 by 7 (feet), 4 by 7 or 4 by 8. With the typical hillside soils I tend to work with in Sonoma County, these planting densi- ties give me vines that are producing a balanced crop and the quality I need for our style, while still being economical to farm. On deeper river bottom- or valley floor- type soils, I tend to plant rootstocks that help moderate vigor, are more drought tol- erant or require less irrigation and can resist or be more tolerant of soil pests such as nematodes or phylloxera. Vine spacing can be tricky on some of these more vigor- ous sites. Too dense can cause canopy- management problems, with shoots growing on top of each other, shading of fruit and difficulty with fungicide penetra- tion, thus causing additional disease pres- sure. Not dense enough usually requires the vines to mature more fruit per vine (to make it economical) and doesn't provide the concentration of flavor or site charac- teristics I am trying to capture while craft- ing those wines. So much of this is really trial and error, and I tend to talk to neigh- boring grapegrowers to find out what has worked and, more importantly, what hasn't worked for them over the years. I am always happy to sit down with a neighbor and share my failures and suc- cesses on a particular site; that's how we all make better wines for our consumers. W&V: How do you arrive at your crop estimates? Cabral: I arrive at a crop estimate pri- marily by counting the number of clus- ters on random vines throughout a block shortly after berry set and using a his- torical average cluster weight to make the initial tons per acre or pounds per vine. For example, in a 3-acre vineyard, I may count 25-30 individual vines to get an average cluster count per vine. I then look at historical cluster weights and try to compare them to what I am seeing in the vineyard now. This method is very non-scientific and relies on a personal judgment call, so this is just a ballpark estimate. But if historically I would har- vest about 24-26 clusters per vine, and the average on this first count is 35 clus- ters per vine, I would go out and drop seven to eight clusters on this first pass and then recount. After the recount, I may wait for the clusters to size up a bit before I determine if another thinning is needed at this time. If I am close—say 26 or 27 clusters per vine on average—I would probably wait until 90% véraison to do a final green drop if the vines seem balanced and happy. This method is fairly time-consuming and can be quite inaccurate, especially when dealing with a new vineyard. We have also begun testing the method of performing "lag weights" on a vineyard for crop load determination. This involves stripping the entire crop off of several vines at a point when you have determined the vine is 50% through the fruit maturation process, counting the clusters and weighing them. Then using a "factor," or an estimate of where the grape is in the maturity pro- cess, you calculate an estimated crop load per vine and then for the entire block. This, "I tend to plant closer spaced vines on marginal sites and look to control vigor on deeper, richer soiled sites." —Bob Cabral The winemaker says he likes to cluster thin right after berry set, followed by the removal of laterals.