Dr. Esmaeil Fallahi, a founder of the Idaho table grape industry, has tested many different varieties.

Dr. Esmaeil Fallahi, a founder of the Idaho table grape industry, has tested many different varieties.

Idaho has a burgeoning table grape industry with more than 40 commercial growers. Though the idea of growing table grapes in the famed potato state was greeted with skepticism and ridicule a decade ago, growers are finding that certain varieties grow better there than in California.

When fruit physiologist Dr. Esmaeil Fallahi joined the University of Idaho at Parma in 1989, southwestern Idaho had a wine grape industry but produced no table grapes. Fallahi observed that the climate was similar to that of his home country of Iran, where grapes have been cultivated for thousands of years, and he planted 26 table grape varieties in a trial. When those proved successful, he added more.

Grower Ron Mann of Payette, one of the first in Idaho to grow table grapes, said he and Fallahi together have tested about 140 varieties. "And we’ve narrowed it down to about eight to ten that do extremely well."

Fallahi said current trials include 27 selections developed by Dr. John Clark at the University of Arkansas’s table grape breeding program.

"Some of those varieties are showing outstanding results, and obviously they don’t grow them in California or other areas," he reported. "When they’re released, that would be very positive."

Idaho can successfully grow many of the same varieties as California, including the deep red Flame and the blue-black Autumn Royal. An Australian variety called Ralli, which he describes as fluorescent red orange with good flavor and storability, grows better there than in California. Fallahi said all the industry needs are four or five good varieties that produce large, crunchy, flavorful berries.

Table grapes seem best suited to southwestern Idaho, the state’s main agricultural region. Areas further north would not have sufficient degree days.

Many growers from Washington have attended Fallahi’s field days at Parma, and he is hoping to begin a cooperative table grape project with growers in Washington’s lower Yakima Valley or Tri-Cities areas, which have similar climates.

Fallahi said some buyers prefer the flavor of grapes produced in the Pacific Northwest. The warm days and cool nights in September contribute to the intense black or red color, whereas in warmer areas growers sometimes treat the crop with Ethrel (ethephon) to enhance coloring.

Varieties grown in Idaho must be able to survive cold winters, but Mann notes that growers in the Pacific Northwest have long grown wine grapes, so there’s no reason they can’t grow table grapes. The only major difference between the two is that table grapes produce much heavier crops and need sturdier trellis systems.

To avoid winter damage, growers need to shut off the water to the grapes in August to harden off the vines, Mann said. "That’s contrary to any other fruit they grow, but if they don’t follow that and you get a good freeze in October, then it will catch those plants that are still green," he warned.

Fallahi tells growers that they should expect winter damage one year out of ten, though he suspects that global warming is influencing the climate. The area’s last major freeze, which killed vines to the ground, was in 1990-1991.

"I always, in my meetings and teachings, warn growers about two things," he said. "Make sure you get virus-free material in the state, and the other is that they’re taking a chance. There’s no crop we can grow that we don’t have risk—the risk of the market or the weather."


Mann said he’s had no trouble marketing his table grapes, and could sell more if he had them. Idaho growers are at a competitive advantage in local markets because there are no shipping costs added, and because shoppers like to buy local foods.

"You have those large grocery chains, and they will buy wherever they can get the best price, but, on the other hand, there are a lot of independent markets that really love local grapes—the farmers’ markets and smaller grocery stores," Mann said. "Now we’re finding that some of the big chains are being forced, just by the demands of their customers, to buy locally, which I think is very healthy."

Mann believes the buy-local trend will only strengthen with increasing concern about imported foods.

Fallahi said the Idaho table industry is not competing with the California industry, which produces 97 percent of the nation’s table grapes, but is complementary to it. California’s harvest runs from late spring to fall. The Idaho harvest runs from late August or early September through late October, by which time most of California’s Flame grapes have been harvested. With better storage, Idaho might be able to have grapes available for a month longer, filling a market window before grapes from Chile come onto the market in January.

He thinks there’s potential for California producers, who ship grapes to Canada, to plant vineyards in Idaho and produce grapes closer to their destination to reduce transportation costs.

Mann expects the Idaho table grape industry to expand to 3,000 or 4,000 acres, and thinks that within the next two or three years, the Idaho Table Grape Association will form a central storage facility and market grapes for the smaller producers who have just a few acres.

He noted that Idaho has only half the apple production it used to have, and table grapes appear to be a good alternative to fill the void and keep farmers in business. He’s also growing chestnuts and testing other new crops from around the world, such as berries from Mongolia, Russia, and East Germany. "We’re excited to see if we can get other things going," he said.