DECORAH, Iowa — In the extreme northeast corner of Iowa, on a grassy hillside ringed by meadows, limestone outcroppings and prismatic trout streams, an underground bunker safeguards our nation’s food heritage.

Inside the surprisingly small 10-by-15-foot freezer vault at Seed Savers Exchange, floor-to-ceiling metal shelves are packed tight with white cardboard trays full of moisture-proof, foil-lined packets. The packets, labeled with long sequences of numbers and letters, hold the seeds of more than 25,000 varieties of old-time vegetables and plants.

This treasure trove of heirloom edibles is a living testament to the rich diversity of foods North Americans used to eat. But Seed Savers Exchange is more than just a repository. The nonprofit organization is the largest seed bank in the nation that makes its seeds available to the public, with the goal of reintroducing these nearly lost foods to backyard gardens, commercial farms and ultimately the American diet.

“We are the anti-Monsanto,” executive director John Torgrimson says. “We are the safety valve. Before World War II, every farmer saved seeds. Today, patented seeds and hybrids make it impossible for farmers to save seeds.”

Torgrimson says Seed Savers Exchange is also the backbone to the heirloom seed movement. “There’s a good chance that a restaurant in New York is able to offer heirloom tomatoes on its menu because we’ve been doing this work for 34 years.”

Planting a seed

It all started with the seeds of two plants from Bavaria.

Diane Ott Whealy grew up on a farm near Festina, Iowa. Her paternal grandparents also had a farm nearby.

Shortly before her grandfather died in 1974, he entrusted Whealy and her husband, Kent, with seeds for two beloved plants that he had always grown: a large pink tomato and a red-throated purple morning glory.

Her grandfather’s father had brought the seeds for both plants to the United States when he emigrated from Dreuschendorf, Germany.

The Whealys realized they were the last people in the family to have the seeds, and that got them thinking about the loss of genetic diversity in food crops nationwide. They wrote letters to Mother Earth News and other back-to-the-land magazines to try to find other people who were also saving heirloom seeds.

In 1975, the couple started True Seed Exchange out of their remote homestead in Princeton, Mo., 115 miles northeast of Kansas City, Mo. That first year, they printed a directory of gardeners who had seeds to share and sold it to 29 people who sent in 25 cents and a large envelope.

True Seed Exchange became Seed Savers Exchange in 1979 and moved to Decorah in 1986. Today Heritage Farm, as the headquarters is known, employs 50 people who work in the organization’s research lab, trial gardens, greenhouses, visitors center and retail seed operation and generates $5 million per year.

“We started doing this before heirlooms were fashionable,” she said. “We knew in our hearts it was the right thing to do.”

Ott Whealy says it took a long time for the public to realize it needs the seeds her organization has worked so hard to find and distribute, but that only sweetens the gratification she feels now.

Kent Whealy left Seed Savers Exchange shortly after the couple divorced in 2004, but Diane Ott Whealy remains vice president and spiritual center of the organization.

The heart and soul

Seed Savers Exchange is best known for its online and mail order catalog, which offers 600 varieties of heirloom vegetables and plants. The catalog is hugely popular among gardeners who devour its beautiful color photographs and especially the descriptions, which are essentially little stories about the history of each plant and the people who saved its seeds.

As charming and profitable as the catalog is (seed sales bring in about 70 percent of the organization’s annual revenues), the heart and soul of the organization, the “exchange” part of Seed Savers Exchange, is the members-only yearbook, a listing that allows seed savers to connect with each other to trade, give away or buy and sell seeds.

Currently the organization counts 13,000 members in all 50 states and 40 countries. Membership costs $40 per year and includes a copy of the yearbook and other publications relating to gardening and seed saving. The 2013 yearbook lists 12,495 different varieties of heirloom vegetables and plants offered by 694 member growers. It includes 4,749 varieties of tomatoes, 875 types of peppers and 1,553 beans. The organization also provides monthly webinars at seedsavers.org that teach techniques for gathering and storing seeds.

“We did not just save the seeds,” Ott Whealy said. “We gave people back the knowledge about how to save the seeds that had been lost.”

Seed Savers Exchange has specific criteria for including a vegetable or plant in the preservation collection. The first is botanical: the seed has to be open-pollinated, meaning, unlike hybrids, if you save the seeds and plant them, you will get the same plant. The rest are cultural.

“It’s like ‘Antiques Roadshow,’” executive director Torgrimson said. “We have to have the provenance. We know it was in a seed catalog in 1898 or we know it was handed down generationally within a specific family.”

Most heirloom varieties are pre-1950, before hybrids (which do not come true from seed) exploded onto the scene. But there are exceptions: the Green Zebra tomato was bred by a Seed Savers Exchange member in 1983. It started as a cross between two other tomatoes, but the breeder was able to stabilize the plant so that it now grows true from its seed.

A scientific approach

Its level of scientific research sets Seed Savers Exchange apart from other seed banks, says David Dierig, manager of the USDA’s seed bank in Fort Collins, Colo., where Seed Savers Exchange backs up its collection. The government seed bank is interested in the genetic profile of plants and serves mainly plant breeders and researchers looking to find or develop plants with increased resistance to, say, pests or drought.

“Seed Savers Exchange is documenting the provenance and cultural significance of plants. We are not set up to go out and find those stories. They are performing an important and unique function,” Dierig said.

Most of the seeds in the Seed Savers Exchange preservation collection are food plants, but some flowers are included as well.

By late July, the front of the enormous red barn next to the visitors center will be cloaked in Grandpa Ott’s morning glories. The first seed ever offered by Seed Savers Exchange is now one of the most popular varieties in the country and can be found for sale even in mainstream Burpee’s seed catalog.

Ott Whealy explains why an organization that focuses mainly on heirloom food plants is interested in saving old flower varieties. “If you want to grow food in your backyard nowadays, you also need to grow flowers to attract the pollinators. That didn’t used to be the case, when farms and yards were surrounded by flowering trees and fields of wildflowers.”

Another nonfood aspect of Seed Savers Exchange is its collection of heritage livestock breeds.

Behind a split rail fence on a hill, above a trout stream that flows through the farm, several white cattle with black ears and lyre-shaped horns stand munching the lime-green grass.

These are ancient White Park cattle. They originated some 2,000 years ago in the British Isles. Today, the herd at Heritage Farm is one of only two breeding herds in the U.S.

The farm is also home to heritage pigs, turkeys, ducks and chickens. The animals are a big hit with the 15,000 visitors that come to see the farm and hike its 8 miles of trails each year. But the animals are there for more than scenery. An integrated agricultural system is a tenet of the organic farming practiced at Heritage Farm. Chickens running through lettuce beds eat bugs and fertilize the soil, and pigs turned out to roam in orchards loosen the soil and eat fallen fruit that otherwise would rot and attract bugs and mold.

Special seeds

Bear Paw

“A popcorn developed by Glenn Thompson of Vermont. Glenn grew and distributed Bear Paw throughout New England from the 1930s until the mid-1960s. This popular variety was served in New England homes and movie theaters and was featured in the Vermont exhibit at the World’s Fair. When Glenn’s health declined and he was no longer able to keep up production, Bear Paw became hard to find. His daughter Ginny has fond memories of the popcorn. She tells how her father hired local boys to help with the harvest. When work was done for the day, the boys were often invited in for cocoa and cupcakes. Ginny and her children remember sitting on Glenn’s lap while the corn was popping over a coal burning stove.”

Speckled Cranberry

“Brought to America from England around 1825. Triple purpose bean. Can be used as a snap bean at around 60 days, green shell bean at around 80 days, or as a dry bean if grown to full maturity. Produces heavy crops of stringless 7-9” pods until the first frost.”

Hidatsa Shield

“From the Hidatsa tribe who raised corn, squash, beans, and sunflowers in the Missouri River Valley of North Dakota. Shield Figure beans are described in ‘Buffalo Bird Woman’s Garden’ (1987). This very productive variety was boarded onto Slow Food USA’s Ark of Taste in 2005.”