With so much attention on drought in California, and how it's affecting all agriculture, it should come as no surprise that the topic of dry farming is getting some attention. There is a fascinating article in Growing Produce explaining requirements for dry farming winegrapes as far as weather, soil, the vines you plant and how you plant them. And it's not a technical, dry (ahem) read.
Some of the highlights of this article, written by Water Program Coordinator for Community Alliance with Family Farmers Kendall Lambert, regarding dry farming? First, you'll need a site with at least 15 inches of annual rainfall, though some growers are having success with less. And look for deep soils that hold water. Sometimes you can just look around and get a feel if it's spot where dry farming is feasible, as Dave Osgood, who dry farms winegrapes in Paso Robles, explains, "See what grows there naturally. If it is only dry grass land, then it may be hard to dry farm, but if you have oak trees, shrubs, flowers, and grasses, then you have water in the soils.”
Don't forget to select rootstocks that promote vines with deep, extensive root systems. And space out those vines wider than if you employed irrigation.
One other benefit of dry farming is not having to install all that irrigation equipment and infrastructure. Osgood states that while you'd have to spend up to 40,000 dollars per acre to plant an irrigated and trellised vineyard, it's only around 6,000 per acre for a dry-farmed vineyard. (This is excluding land costs, and it takes longer for a newly planted dry farmed vineyard to bear fruit worthy of turning into fine wine.)
Are you interested in knowing if the grapes in your wine were dry farmed? Is it important to know that winemakers and grape growers are doing everything they can to conserve water if their vineyards are in a spot where dry farming is possible?