A tractor rumbles across a field of dark red earth at Twin Bridge Farms on O‘ahu’s North Shore. It’s pulling a planting machine, and farmhands riding the machine monitor hoppers full of nugget-size potatoes, which fall through chutes into instantly dug holes. Rotating steel discs bury the potatoes in parallel rows of mounded dirt.
Walking behind the tractor are Alan Westra, a plant pathologist from Idaho, and his assistant, Kimberlee Yonke, who tracks on her laptop which potatoes are planted where. These tiny tubers are a specialized crop—seed potatoes. While Hawai‘i is known as an agricultural cornucopia where almost anything will grow, potatoes aren’t among the crops that usually spring to mind. But in fact Hawai‘i—and Twin Bridge Farms in particular—is a critical part of potato production throughout North America. All full-size, commercial potatoes grow on plants that have sprouted from seed potatoes. In Idaho alone, sixty-five to seventy major growers raise two hundred different varieties on thirty thousand acres of land. But before they can be sold as certified potato seed, they must pass a winter grow-out test. Each year’s seed potato crop is harvested in September or October and stored. A sample from every batch is selected and shipped to Hawai‘i—thirty-five thousand pounds in all—and planted in November. When the stems and leaves emerge in December, Westra returns to inspect the foliage, pick leaves and ship them back to Idaho to be tested for viruses and other diseases. Eight potato-producing states, plus four Canadian provinces—accounting for about 80 percent of all North American production—test their seed at Twin Bridge Farms.
Owners Milton Agader and Al Medrano started the farm after Waialua Sugar shut down in the 1990s; the pair also grow asparagus, sweet potatoes, tomatoes and more on their three hundred acres of former cane land. But just in the last decade, the farm has become America’s seed potato hub. The winter tests were once conducted in Florida or California, but conditions are superior in Hawai‘i. “In California there were always issues with frost damage and insects,” says Westra. “Here, there’s no issue with frost, and the growth is phenomenal. Nowhere else could we get our results so quickly.”