Head toward northeastern Iowa, through rolling hills and winding streams and you'll find Heritage Farm — 890 acres where seeds reign supreme.
At the end of a gravel road at the farm is a vegetable garden, and Marta Behling picks through a bush of cherry tomatoes called Mexico Midgets. They're about the size of a ping pong ball and they've grown on cages about six feet high. Every time Behling brushes up on their leaves, they release a fragrant, sweet aroma.
Recent cold snaps have seasonal workers like Behling putting in extra hours to harvest these bright, red heirlooms — not to sell them as fruits, but to crush them up and extract their seeds. The tiny tomato is one of 4,713 tomato varieties in the Seed Savers Exchange, where for more than three decades gardeners have swapped and stored seeds from heirloom plants.
In all, the exchange maintains more than 25,000 varieties of heirloom vegetables, herbs, flowers and plants — everything from Red Swan Beans to Teddy Bear Sunflowers. Members list their seeds in a yearbook and Seed Savers grows a select number of varieties in one of its 20 gardens each year.
The tiny seeds of the Mexico Midgets are extracted by hand, or with a large seed extracting machine, like the one Laura Cochran preps in a garage at Heritage Farm.
"It's sort of like if you have a bucket of tomatoes and you actually stomped on them and then separated the seed and the juice out from it," Cochran said. "The machine does all that for you."
Cochran and a colleague dumped two buckets of Angora tomatoes into the machine, and within seconds, the seeds appeared from one end and the skin and flesh from another. From here, the seeds are dried and stored in one of several walk-in coolers or vaults on the property.
The main purpose of the exchange, one of the largest non-profit seed banks in the country, is to protect the genetic diversity of North America's plants that are going extinct. According to the Food and Agriculture Organization of the United Nations, about 75 percent of plant varieties have been lost as farmers around the world have moved to mechanized, high-yielding varieties.
"There was a time in American farming when most farming, almost all farming, was sustenance based," said John Torgrimson, executive director of Seed Savers Exchange. "Very few farmers nowadays actually consume things that are grown on their farm unless they've got a garden of some sort. I think that's kind of sad."
Sad, but also a cause for concern. Torgrimson said future climate change or disease might wipe out one of the limited number of plants varieties we depend on.
That's one the reason the exchange regenerates seeds each year. Workers select the seed either because it exists in the collection in limited quantities, or because its germination rate is decreasing. The Edmonson cucumber, for example, was reintroduced this year at the exchange after not being commercially available since the early 1900s.
"Eventually we grow most everything," said Aaron Burmeister, a Seed Inventory Technician at the exchange. "After a certain period of time, even in ideal storage conditions, that germination rate will start to decrease so that's something we attempt to monitor."
Generations of gardeners have helped grow the collection by donating seeds, and often by leaving written instructions, said Sara Straate, the seed historian at the exchange.
Among the handwritten letters in a thick file folder is one from 1987.
"Enclosed, please find squash seeds that have been in my family for many years," wrote the donor. "My mother said her and her mother received them from relatives who lived in Oregon and not knowing the name of them, they have always called the Oregon squash. They have a blue and green skin, small seed cavity and a medium sized fruit."
Straate said documenting each seed's history is just as important as preserving the seed itself.
"Some families have grown a particular bean or pea for over 100 years," she said. "We hope to save all of those stories associated with the seeds."
The seeds are stored in an underground freezer vault at Heritage Farm. Backup seed samples are also sent to the National Center for Genetic Resources Preservation in Ft. Collins, Colorado and at the Svalbard Global Seed Vault in Norway. The deposits made by the exchange remain the property of the Seed Savers Exchange and cannot be distributed to third-parties.
A farm in Iowa may seem like an unsuspecting place to keep so many unique seeds and their stories.
But the way Straate and others there see it, it's all an effort to save endangered crops before they're gone for good.