John DeRoseir at his farm in Paso Robles, California

John DeRosier’s With the Grain farm grows a diversity of grains without irrigation during the winter and summer months, even when the temperature consistently tops 110 degrees Fahrenheit in Paso Robles, California. He is a dry farmer.

The concept was implausible at first. I asked him several times to explain, “How is it you can farm without irrigation while all the neighboring farms are drilling 1,000 feet beneath the surface?” I pointed to the surrounding sea of grapevines which clung to the soft hillsides.

“It starts with the cover crop,” he told me.

Only 3 percent of U.S. farms reported growing cover crops in the latest Census of Agriculture, and the practice drops with farms larger than 200 acres. Cover crop is important, as I learned from John because the decaying plant material from the cover crop feeds the microorganisms in the soil.

This process builds the soil organic matter (SOM). SOM can retain up to 10,000 times more water than soil without, according to the USDA Natural Resources Conservation Services. While his neighbors drill deeper wells to excavate water to irrigate wine grapes and almond trees, John’s crops grow with the moisture held between the granules of soil.

Last year, John wasn’t able to deliver grains to his CSA customers. “The margin of error for dry farmers is narrow,” he recently told me. “The winters are drier now. I have to plant  earlier than before.” In the fourth year of the drought, he will harvest 150 acres of grain.