What is dry-farming? We asked our friend, Ryan Stirm @stirmwineco, a viticulturalist, soil scientist and winemaker. “Dry-farming is the practice of farming without the use of supplemental irrigation— relying completely on the rainfall (and subterranean water) that occurs on the plot of land being farmed. Drip irrigation as we know it was invented and developed in Israel in the 1960’s to farm crops in desert climates with limited access to irrigation water. Drip irrigation is used to establish vineyards and increase yields.” To keep things simple, dry-farming has several potential quality advantages over drip irrigation:
Dry-farmed vineyards tend to have deeper root systems. This is because roots grow where the water flows; vines don’t want to work hard for water if they don’t have to. If digging deep is the only option for survival, they’re gonna go deep! Drip irrigated vines tend to have clustered root systems at the surface because the water supply located there. Frequent shallow irrigation in one particular spot will keep roots from exploring deeper into the soil, picking up interesting nutrients along the way that would potentially increase the complexity of the grapes it produces.
The soil near the surface tends to be the highest in organic matter and most fertile. When coupled with plentiful water, you can get the idea That the fruit is more likely to be of the low-quality, high-yield variety.
Dry farmed vines with developed root systems have the beauty of not relying on an outside water supply and can access the more steady supply deep below the surface, rendering big heat waves less dramatic for them. In our home state, California, this translates to the vines being slower to metabolize their malic acid, which slows ripening, improves acid retention with less sugar development and more physiologically ripe grapes!
Irrigation (especially late in the season) promotes more vegetative growth (via the hormone auxin) and trick the vines, keeping them growing and developing more sugar in the fruit, at the expense of ripening the seeds. Physiologically, dry-farming promotes the healthy development of all of the plant hormone cycles throughout the year. It saves an enormous expense on vineyards and can potentially makes better wine.