Thibaut Scholasch holds a PhD in grape growing. He understands pretty much everything you want to know about how a plant conveys water and nutrients to its extremities. Now he's bringing a data-driven approach to irrigation.
Wired on: The Vine Nerds:
Napa Valley’s oldest wineries were established in the mid-1800s. Its pioneers took their cues from the finest French producers, like those on Bordeaux’s famed Left Bank, where winemaking dates back to the 12th century. There, frequent summer rains provide ample groundwater and allow vineyard managers to pack their fields tightly with vines. So the early Napa farmers planted their fields in a similar manner. “They assumed that if you copied and pasted the best vineyards, they would produce the best fruits,” Scholasch says.
But Napa isn’t Bordeaux. Soil composition and sunlight differ, and it typically rains very little in Napa between May and October. Certain grape varieties in certain parts of the world are dry-farmed, meaning the only water supply is Mother Nature. But not Napa’s famed cabernet. Here farmers have historically hacked the climate to make it resemble France’s, faking early rain to provide vigor, trimming the leaf canopy to gain sunlight, and packing the vines closely together. “We could go without irrigation entirely if we had been smarter about configuration and planting density,” Scholasch says. “Applying the wrong sets of rules set up a need for irrigation.”
Over-irrigating a vineyard isn’t just wasteful; it’s counterproductive. To understand why, there are a few important things to remember about grapes, especially the varieties used to create high-quality wine. First, they grow on vines, which require support to reach sunlight. Once the vines encounter light and water, they enter the so-called vegetative state and sprout leaves. But when resources are scarce, the vines become stressed and rush ahead to the reproductive state, ripening berries in hopes of escaping to a more resourceful area by way of a bird. That’s why many of the finest wines are produced by vines planted in rocky, nutrient-poor hillsides with good drainage. The desperate vines focus much of their energy on the berries from the get-go and so reach optimal ripeness more quickly. The last thing to know: Unlike elsewhere in agriculture, bigger fruit isn’t the goal. Water provides girth—and that’s bad. Since the skin provides most of the flavor, it’s far better to have pea-sized berries with a high ratio of skin to flesh.
This is why Fruition may advise clients to deny water early and irrigate deeply once ripening is well under way. At that point, the vine focuses its nutrients on flavoring the fruit. The Frenchmen also sometimes recommend not irrigating before heat spikes or at the first sign of wilting; this advice can be especially hard to take. We all see a droopy leaf and conclude that the plant must be thirsty, but watering at that point actually undermines the complex mechanisms a vine uses to conserve resources and can even cause shriveling. “People think that the plant kingdom behaves like us,” Scholasch says. “But plants aren’t designed to tell the human eye what they need. They have over 400 million years of evolution on us and very subtle ways of coping with heat and water regulation.”
Not everyone, however, is on board with the data-driven approach. Brad Grimes of Abreu Vineyard comments “for us, farming is about gut feeling, common sense, and the relationship we have with our properties.”