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In California, dry farming creates sweeter tomatoes

Posting in Food

In the scorching heat of a California summer, unwatered gardens are producing sweeter, more flavorful fruits than those available in mainstream supermarkets. Commercial growers call it "dry farming," and it could become an important agricultural practice in the future, when water will likely be a less abundant resource. NPR reports.

The idea behind dry farming is that by restricting a plant's water intake, its fruits wind up with less water content and a greater density of sugar and other flavor compounds.

This unconventional technique seems to be catching on throughout the Golden State among small producers of tomatoes, apples, melons, potatoes, and grapes.

It’s more complicated than just not watering plants:

  • Sandy soil (where water drains easily) doesn't work.
  • Plants or trees must be dry-farmed from the time they're planted. If they need some water to get going, it’s still cut it off after a few weeks.
  • As young, rapidly growing vines become thirsty, they send their roots deeper underground than they otherwise would to find moisture, which can remain in the soil all year.
  • To lock water underground, farmers frequently till the top foot of soil into a fluffy dust layer that underground moisture can’t break through.

There is, however, a major drawback. Farming without irrigating dramatically reduces yields.

Dry-farmed trees produce up to 15 tons of apples per acre per year; irrigated trees bear as much as 50 tons. Dry farmers might harvest 4 tons of tomatoes each summer and fall; conventional growers may reap 40 tons per acre.

Actually, in most areas of conventional agriculture, dry farming is unprofitable -- except much of America's grain production and most European wine grapes. (Smaller grapes have a lower juice-to-skin ratio, and since the skins contain flavor-making tannins and polyphenols, dry farming, in theory, produces richer, more intense wines.)

But many dry farmers do so only because they have no water to irrigate their land, according to Paul Vossen from University of California Agriculture and Nature and Resources. "They do it because they have to, and so they'll make it part of their marketing strategy.”

At a Whole Foods in Sonoma County, for example, dry-farmed tomatoes have become a shopper attraction.

[NPR]

Image: dry farmed Early Girl tomatoes / Happy Boy Farms

— By on August 28, 2013, 5:12 PM PST

Janet Fang

Contributing Editor

Janet Fang has written for Nature, Discover and the Point Reyes Light. She is currently a lab technician at Lamont-Doherty Earth Observatory. She holds degrees from the University of California, Berkeley and Columbia University. She is based in New York. Follow her on Twitter. Disclosure