While the word “heirloom” may call to mind old knickknacks or family treasures, heirloom vegetables have been popping up on menus with increasing frequency as chefs and diners alike have come to appreciate their nuanced flavors and unexpected applications.

Heirloom vegetables are those grown from seeds that have a lineage going back several generations. Hybrid seeds, which are the more common variety, have been crossbred between two different seed varieties to produce certain traits. Hybrid plants are often more productive than heirlooms, yielding more fruits and vegetables in a shorter period of time. For this reason, hybrid seeds have come to dominate the agricultural industry.

However, some chefs are now moving away from hybrid vegetables, which are engineered to produce uniform results and can sometimes highlight visual appeal over taste or nutritional value. In contrast, heirloom seeds often grow the most flavorful produce, which is why their seeds have been preserved through the years.

“Heirloom varieties offer up unique qualities like size, color, flavor and texture,” says Tim Kolanko, executive chef at Urban Kitchen Group in San Diego. With three restaurants in the area, Urban Kitchen Group is one of the city’s biggest advocates for the use of heirloom vegetables. Kolanko prizes heirlooms for their individuality, noting that certain varieties are best suited for particular dishes. “Each individual variety of vegetable has characteristics that perform differently in different preparations,” Kolanko says. “It simply gives chefs more options to find inspiration.”

The incredible diversity of heirloom vegetables is also one of the biggest draws for Clark Barlowe, chef at Heirloom restaurant, located in Charlotte, North Carolina.

Heirloom’s hyper-local and seasonal menu means that Barlowe can adapt his six-course tasting menu every day to highlight the best characteristics of the produce he receives from more than 70 local farms.

READ MORE: Meet the Three Restaurants that are Bringing Heirloom Ingredients Back into the Kitchen

When considering heirloom versus other vegetables for his menu, Barlowe says, it’s an easy decision. “The flavor, color, quality, and general appearance are all superior with heirloom vegetables when compared to conventional vegetables,” he says. “The variety in a single ingredient—for example, a tomato, something as small and sweet as a Red Currant tomato when compared to a Green Zebra or a Red Bison—is what makes them unique.”

In creating his menu, Barlowe considers how best to highlight each ingredient, bringing out the characteristics that have been passed down through the many generations of seeds. He finds red currant tomatoes to be best pickled, while the Green Zebra’s high acidity makes it perfect for salads. And Red Bison tomatoes, Barlowe says, make outstanding sauces.

But taste isn’t the only thing that chefs value about these veggies. Heirloom seeds are also crucial to creating a more sustainable food system. “Using heirloom vegetables directly supports farmers and seed producers working hard to bring more delicious vegetables into our food system,” Barlowe says. By buying produce from local, family-owned farms that focus on growing quality ingredients, chefs can help to boost a fragile ecosystem that has been severely damaged by large companies focused on profit, not quality.

At Urban Farmer in Denver, executive chef Chris Starkus takes a commitment to heirloom vegetables one step further by running his own farm, Lost Creek Micro Farm, which grows vegetables for restaurants all across the city as well as the local community. Starkus says that open pollination—the practice of allowing seeds to be pollinated by natural mechanisms such as wind—is vital to keeping small farms alive.

Hybrid plants produce seeds that are genetically unstable and cannot be used year after year the way heirloom seeds can. “Open-pollinated seeds are huge for small farms,” Starkus says. “It means that they can save their seeds each year, not only to save on seed costs, but to also have consistent quality and hearty varieties adapted to your specific grow zone.”

Without the work of farms like Lost Creek, it’s possible that many heirloom vegetables would disappear. “Industrialization and the resulting homogenization has lessened the number of varieties of vegetables being grown,” says Urban Kitchen Group’s Kolanko. While that industrialization has allowed produce to be grown on a larger scale than ever before, it has also made it vulnerable; were hybrid produce to be affected by a disease, it could have devastating repercussions.

For this reason, Kolanko says, diversity is necessary for the health of the food system. “It’s important to support the people growing heirloom varieties so we can maintain the breadth of variety in terms of ingredients being produced,” he says.

The breadth can be seen every dish at Heirloom, where the duck confit is served with heirloom purple cabbage and radishes and the rabbit meatloaf comes with two types of honey-glazed heirloom carrots. The techniques may have changed (our ancestors probably weren’t wrapping their meatloaf in bacon), but the soul of the dish is one that has carried over through multiple generations. And a hundred years from now, another restaurant might be serving those same purple carrots as part of a dish that hasn’t even been conceived of yet. At least, these chefs say, that’s the hope.

• Go For The Grains – Vegetables aren’t the only heirloom ingredients in town. Ancient grains are showing up in dishes across the country, like the pan-seared salmon with heirloom quinoa at Honey Salt in Las Vegas and the grain porridge at Denver’s heritage, which includes farro medio, spelt, barley, Abruzzi rye, and einkorn wheat.
• Tons Of Tomatoes – Tomatoes are one of the most popular heirloom vegetables, with good reason. Their versatility makes them an ideal addition to a wide range of dishes and cuisines. At 312 Chicago, they use heirloom baby tomatoes from their rooftop garden as the perfect topper for their crostini di burrata.
• Corn On (And Off) The Cob – There’s more to corn than what you see at the supermarket. Native Americans have been growing dozens of varieties of the summer treat for centuries and have been instrumental in keeping heirloom corn alive. In addition to tasting great on the grill, heirloom corn is also used in whisky production. Check out Sierra Norte or Pierde Almas brands, both distilled from native Oaxacan corn.