It’s that time of year again: Pruning. All year long the vines’ “hair” is allowed to grow to hippie-like length and then come late winter we treat them like they are reporting to boot camp by giving them crew-cuts. In fact, in almost all cases we are pruning up to 95% of the previous years’ growth. At Upland Estates we grow cherries, apricots, nectarines, peaches, prunes, pears, apples, juice grapes, and wine grapes. Every winter we have to prune them all but not one of those other fruits ever comes close to the wine grapes’ 95% number. Why, you ask? Two reasons: the way a vinifera (wine grape) vine grows and most importantly, quality.
Vinifera: First, let’s concentrate on how a vinifera vine grows. As a shoot on a vine grows, it forms nodes; each node being separated by a bud. Ideally, you want to let each shoot get approximately three and a half feet long during the growing season. Typically, each node will be around 2.5” long. Therefore, each shoot will contain roughly 17 buds. These buds are what determines next year’s crop. Each bud normally contains two clusters of grapes and an average cluster will weigh about 0.3 lbs. Now consider that a usual vine will have roughly 30 total shoots before pruning. That would amount to 300 lbs of fruit per vine if left unpruned! Ideally, we are looking for 6 to 15 lbs, depending on the price point of the ultimate product, but more on that subject later.
Physiologically it is impossible for a vine to produce 50 lbs of fruit per vine, let alone 300, and this is for two reasons. One: the more fruit you have hanging on the vine, the less sugar each cluster will have and you need a certain brix (sugar measurement) to make a decent wine. Two: the more buds you leave on last year’s shoots, the more sporadic your fruit set will be because the vine will automatically abort excess buds due to a limited amount of energy. In other words, if you don’t prune hard enough, you will be forcing the vine to do more than it is comfortable doing. When this happens, the vine will exert too much of its energy early in the season, hence greatly affecting my next topic: quality.
Quality: To make the best wine possible, wineries need the best fruit possible, which sounds simple enough until we start analyzing just exactly what it is that goes into growing quality grapes. Generally speaking, there are different levels of quality and those levels are all driven by one universal thing that we are all familiar with: money. The quality level is usually determined by the price of the bottle of wine that the fruit is going into. To grow the best grapes possible, us growers need to grow less grapes per vine and make many more manual labor passes throughout the year in the vineyard. The more passes with our skilled workforce we make, the more our money spent per acre goes up. Likewise, the less fruit we put on our vines, the more money we need to get per pound (or ton) in order to meet what the banker has deemed our ideal bottom line. Take Cabernet Sauvignon for example. On Snipes Mountain, we can get Cab ripe (25+ brix) at six tons per acre. It will also make a decent wine at that tonnage if other key viticultural practices are followed. I say “decent” because it may not have the ideal color, fruit intensity, or complexity that you want in a high-end bottle of wine. It will be a perfectly fine bottle to have with your homemade spaghetti during a family meal (with red sauce, of course), but you wouldn’t necessarily want to take that bottle to a five star restaurant to pair with your rare elk loin, chanterelle duxelles, and black currant demiglace.
For winemakers to achieve an ultra premium cab from Snipes Mountain that truly is ultra premium (and not just pricey), they need to start with fruit that is cropped around three tons per acre. But to get to this point, we will have to pass over every vine by hand at least ten times during the growing season. In comparison, that “decent” six ton cab might only require four passes. This can make a huge difference to a farmer’s pocketbook when minimum wage is $9.04 per hour. In addition, the detail required for many of the “three tons per acre” passes is such that you may have to pay well above $9.04 in order to get the skill set you desire.
The point of all my rambling is that the end product of these quality passes starts with pruning. To minimize work throughout the growing season, I want to prune as aggressive as possible while at the same time leaving a little “insurance” in the form of a couple extra buds to compensate for what Mother Nature may throw my way. If I leave too many buds, then I will be leaving extra work for the vine to do, making it much more difficult for that vine to achieve its end goal: ripeness. The same goes for quality. Because I normally know before the growing season how much I will get paid for the end product, I want to minimize work on my vines as much as possible. This is done to gain the maximum dollars per acre that I can, while at the same time achieving quality ripeness.
So remember: If you’re driving by your favorite vineyard in the spring and the vines look naked compared to when you make your annual wine tasting trip in the late summer/fall, it’s all part of a master plan to make your favorite Washington State wine the best it can be!
Adapted from Upland Estates grower Todd Newhouse’s blog: A View from the Tractor.