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Four Ways Grapes Get Water and Why Dry Farming is the Best

Four Ways Grapes Get water and Why Dry-Farming is the best | The Latest | RedThumb Natural Wines

Save water, drink wine [from dry-farmed grapes]

I have a confession to make: I am a great killer of house plants. I do everything I’m supposed to: proper light, good soil, serenade them with music, etc. [Surely they dig Miles Davis and sludge metal?] I think I must go wrong with the watering. There’s a lot to consider: quantity, frequency…well, I guess that’s it really. Still, I am flummoxed. The plants, they keep on dying.

I would classify replacing the houseplants once a quarter as a mid to low-level inconvenience; however, for agricultural businesses [like grape growing], water usage is a major concern. Some crops require massive amounts of water to grow, and often these crops are planted in areas that have little-to-no natural water supply.

For example, it takes about 900 gallons of water to produce one pound of almonds. California, despite its frequent droughts and reliance on other states’ water, produces 82% of the world’s almonds. Meanwhile, Harvard’s $39B endowment is buying up California’s vineyards and their water rights. This is an untenable situation, and as the climate crisis worsens and water becomes even scarcer, there will need to be hard decisions made between profit and responsibility.

There are plenty of factors determining which method of irrigation a winemaker might use; climate and soil composition are two. As a very general rule, grapes need more than 25 inches of annual rain to grow. Anything less than that will probably require some kind of irrigation. Too much rain can result in waterlogged roots, a higher chance of plant disease, or just bad wine. But it’s not as simple as measuring rain. Soil’s water retention and drainage also play a factor. Silty [Napa, CA] or clay-based soil [Right Bank Bordeaux] holds more water than sandy or gravel-based soil [South Australia]. Kids, farming is hard.

Let’s look at four irrigation options winemakers might consider. 

Sprinkler irrigation

We know how sprinklers work: underground pipes, high-pressure sprinklers, water spraying everywhere. It’s not a bad way to keep your soccer fields looking sharp. But with it comes a lot of water waste, and it’s not the best way to deliver the right amount of water to the grapes. So why is it used? 

For one reason, it’s very uncommon for young vines [three years or less] to survive without some supplementary water. The roots just haven’t had a chance to grow deep enough. Plus, it’s not the most expensive irrigation technique, so it’s an attractive option that can yield large amounts of low quality crops. No thanks.

Drip irrigation

The most common method and more efficient than sprinkler irrigation, drip irrigation delivers targeted, precise water amounts right at the root through a series of pipes and distribution lines. There’s less water waste caused by evaporation and runoff, too. All that equipment is expensive, though; between pressure regulators and filtration systems to avoid debris from clogging the lines…it’s a lot. 

But the main rub is that the grapes tend to lack a sense of place, “terroir expression,” if you will. Those unique characteristics of particular wines from specific places are one of my favorite aspects of natural wines. Grapes benefit from a bit of mild water deficit at the right time. These grapes here? These grapes never had to work hard, never built any character, have water delivered to them on a silver platter.

Unrelated: you can find me on the corner, shaking my fist in the air, yelling at children. 

Flood irrigation

Flood irrigation [or surface irrigation] is the oldest irrigation method and involves using gravity to flood a vineyard early in the growing season, soaking the soil, and then providing just enough water for the rest of the growing season. Winemakers in Mendoza, Argentina divert runoff from melting snow in the spring using a centuries-old irrigation system engineered to repurpose what would be wasted water from the Andes Mountains. It’s less expensive than sprinkler or drip irrigation, ecologically sound, and combats worsening drought conditions. It’s also necessary; Mendoza receives less than 10 inches of rainfall a year.

However, there are downsides to flood irrigation. It isn’t always practiced with responsible water usage in mind and can often lead to water waste and over-watered vines. It’s difficult to control uniformity in the amount of water flooding the fields; if not executed properly and in a controlled way, flood irrigation can also strip soil of valuable nutrients that contribute to the flavor and complexity of the finished wine. In the end, it can be just as harmful as the overuse of traditional irrigation.

Dry farming

Our grapes are dry farmed; it’s one of our core standards. This means that no irrigation is used whatsoever in the vineyards. The vines live off of the water that exists in the ground or falls from the sky. This is the most responsible approach to water usage in agriculture: a net zero impact on the water supply available for other uses. There is also a lower risk of mold and other disease in dry farmed vineyards, which makes organic grape-growing a much simpler proposition. 

Aside from the ecological benefits, dry farming has a substantial impact on the quality of the grapes. As vines struggle for water, they send roots down deep into the soil looking for the water table. These resourceful, deep-rooted vines produce more consistent, complex grapes than lazy vines that are “momma-birded” water from the day they are planted. The wine made from dry farmed grapes is just better, and we wear our dry-farmed label like a badge of honor. 

Wine in a changing climate

For many winemakers, irrigation is a necessary part of the growing process. For us, we’ll be sticking with our standard that all RedThumb wines will be dry farmed. But as the effects of climate change continue to make annual rainfall unpredictable, we’re having more difficulty finding new wines that meet our dry farmed standard. We hope that action on climate change will allow us to continue using this standard, and we’re educating ourselves on alternatives just in case.