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A Year In The Vineyard

by David on July 8, 2009

Managing a vineyard, like many of the most worthwhile things in life, is a labor of love. Before planting, the grower must make a thorough investigation of the soils and meso-climate1 on the site to determine what variety will perform best in that situation. He must select the various clones2 and rootstock hybrids3 to suit the inevitable variability of those factors throughout the property. He may decide to vary the vine spacing depending on the anticipated vine vigor, or lack of it, in different areas of the site.

After planting and training a new vineyard over a period of three to four years the grower is rewarded with his first small harvest. Once the vineyard is established, keeping the vines healthy is a year-round project. Surprisingly, the weather experienced in winter can have an influence on the timing, quantity and quality of the harvest to follow.

Winter

Grapevines are like roses in some respects. Once we have some frost in November they drop all of their leaves and go dormant for the winter. This rest is very important to vineyard health and performance in the following season. Like roses, the vines require severe winter pruning which will help to determine how many shoots and clusters will appear in the spring. Almost all of the growth from the previous season is pruned off, so that the vines will bear a small, intensely flavored crop.

If we have a long, cold winter, the vines “sleep in”, and come out of dormancy late. If the winter is mild, they’re likely to wake up (we call it “bud break”) early. Bud break is usually in the middle of March, but we’d much prefer that it be late than early. Early bud break increases the risk of frost damage. A beautiful, clear day in the late winter/early spring can turn into a freezing, cold night. The newly exposed, tender buds will be damaged if the temperature drops below 32° F. The risk lasts through about mid-May. This can lead to many nights of poor sleep for growers all over the valley. Geoff Gorsuch, our Winemaker, may have to get up in the middle of the night several times during these months, to protect the vines from frost using wind machines4 and smudge pots5. The upside of early bud-break is that it can translate into an early harvest and reduce our risk of rain damage on the other end. It all depends on the weather that follows.

Spring

Vines in springEarly spring brings the period we call “great growth” in the vineyard, because the new shoots grow like gang-busters. We sometimes imagine we can see them grow! This great growth creates a lot of work, including weed cultivation and suckering6 or shoot thinning. The suckering is done by hand, and is like a post-pruning. We prune during dormancy with the idea that we’ll get certain results, but inevitably, the vines do as they please, and require more of our attention. Once the shoots are a few inches long, Geoff can begin walking the vine rows to make sure they’re developing well and also to look for signs of disease or nutrient deficiencies. This continues throughout the growing season.

The buds flower and form clusters around mid-to-late May. We are fortunate that the flowers are self-pollinating, so we don’t have to worry about bees or wind to carry the pollen. We only worry about the weather. Too much rain, high winds or excess heat can impair pollination. Again, we are fortunate because most years we go for months without rain after the end of April. The weather is blessedly boring and predictable most years, and generally leads to good “fruit set.”7 Once the crop is set, we count the clusters. Of course, there’s nothing we can do about too few, but if we count more clusters than we believe the vines can ripen well, we drop the excess on the ground right then and there.

Summer

When the grapes first form, regardless of the variety, they look like tiny green beads. They’re not recommended for tasting at that point because they’re highly acidic. They plump and develop amazingly quickly. Usually, by mid-to-late July, they’re 2/3 their full size, and the dark varieties begin to soften and change color (we call this veraison). White varieties like Chardonnay go through a much more subtle color change, going from a bright, spring green to more of a yellow-green as they soften.

During this time, Geoff continues to walk the vineyard to make sure it’s healthy, and he monitors the leaf canopy and clusters to see if we need to do further shoot, leaf or crop thinning. He takes leaf samples to do a “petiole (the leaf stem) analysis”, which just means he’s checking for nutrient deficiencies.

Irrigation may be necessary a few times during the long, dry season, but Geoff prefers to keep it to the minimum. Too much irrigation or fertilization may take away from flavor intensity. He can test the vines in different parts of the vineyard to see if they’re becoming water-stressed and respond accordingly.

Late Summer and Harvest

Harvest at GoosecrossVeraison is the signal that the vine’s energy has shifted from vegetative growth into fruit ripening: the grapes are beginning to get sweet, and the acid is decreasing. It means that soon it will be time to begin “field sampling.” Geoff takes samples from all over the vineyard to monitor the sugar, acid and pH. Repeated monitoring of these numbers over the weeks gives him a ball-park idea of when the vineyard will be ready for harvest. He makes the final decision to harvest by tasting. He’s looking for flavors that are intense and fully developed. He bites into the seed to make sure it’s crunchy and mature. If the seeds are still green, they can impart some very bitter tannins to the wine.

Once the vineyard is ready, we’ve got to be quick! The sugar changes a little every day, and if the weather’s hot, it goes up frighteningly quickly. We pick everything by hand. Our goal is to deliver grapes as perfectly ripe as nature allows, free of leaves, raisins or mold. This is a lot to ask, so each year we hire the same well-trained men who are paid above the industry standard to be selective. The wine can’t be any better than the grapes that make it. The crew begins as soon as it’s light enough to see, and finishes around lunch-time, getting themselves and the grapes in, before it gets too hot.

If we’ve had a “normal” year, we begin to pick early-ripening varieties like Sauvignon Blanc around Labor Day. Warm years may mean an earlier harvest and cool years can cause delays. Usually, by mid to late September the harvest is in full swing and we often finish with Cabernet Sauvignon sometime in October, again, depending on the weather. In 2005 some local vineyards were harvested as late as mid-November. The later the harvest, the greater risk of rain damage, but as it happens, 2005 turned out to be an exceptionally fine vintage!

By the end of October we begin to expect rain and the nights become cooler and cooler. Once harvest is over, we hope for frost because the sooner we have some good, hard frost the sooner the vines will go dormant and we can start our pruning again, completing the annual cycle. Click here for the GCU Napa Valley Vintage Recap to check the quality and characteristics of recent vintages.

Footnotes:

  1. Meso-climate: The climate of a vineyard site, hillside or valley. The term “micro-climate” is used in its place extremely often. Micro-climate correctly refers to the climate immediately surrounding the individual vine canopy (or green growth) and clusters. Vineyard and canopy management will strongly influence the micro-climate, but not the meso-climate.
  2. Clone: A clone is a sub-variety within a grape variety, such as Chardonnay, that has been replicated because of specific attributes such as flavor, productivity and adaptability to growing conditions
  3. Rootstock hybrid: Vines of European origin, called vitis vinifera, cannot be grown on their own roots in most parts of the world due to lack of resistance to certain soil pests. They are grafted onto various rootstock hybrids that are resistant to the pests. Additionally, the hybrids are chosen for other beneficial traits, such as low or high vigor, drought resistance, etc.
  4. Wind machines: Wind machines are powerful fans placed in the vineyard for frost protection. They mix warmer air above, with the colder air settling on the vineyard to prevent damage.
  5. Smudge pots: Also called “vineyard heaters,” they look like stove pipes surrounding the vineyard and burn diesel fuel or oil to warm the vines.
  6. Suckering: Removing unwanted young shoots to keep the vine and crop in balance.
  7. Fruit set (also called cluster set): The overall formation of the grape cluster following flowering. Normal clusters will be fully formed, with very few “shot berries” (missing grapes) and uniform grape size, depending on the variety or clone.

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