What Are Heirloom Tomatoes?

You’ve probably seen gnarled, colorful tomatoes in the supermarket produce section, perhaps off-season, labeled “heirloom.” They may look enough like the real thing, but you won’t get the full story until you taste one.  

If the fruit you’re eating is sturdy-skinned with firm, fibrous flesh and a mildly acidic flavor, it’s probably not an heirloom, but rather a modern hybrid tomato that’s been zhuzhed up with some marketing lingo. 

The real deal — whether green streaked with pink or buttercup-yellow in color — sports a whisper-thin skin. Underneath, the flesh bursts forth with juice that might taste buttery and sweet, or tangy with a punch of umami as it drips down your arm. That’s because this delicate, bulging tomato wasn’t bred to travel, keep well, resist disease, or for maximum yield. Rather it’s a pure, fleeting taste of summer. 

“There’s a lot of focus on visuals, but the main way to tell if you’re eating an heirloom [tomato] is flavor,” says Benjamin Pauly, master gardener at Woodstock Inn & Resort in Woodstock, Vermont, who has grown some 250 heirloom tomato varieties in high, covered tunnels at the inn’s Kelly Way Gardens since 2013. This year he is growing 51, which guests can sample at the 9th Annual Great Tomato Tasting in August. 

“If [a tomato] tastes good, it is good,” says Pauly. “There’s a Miles Davis quote I love that’s similar: ‘If it sounds good, it is good.’” 

What is an heirloom tomato?

To be considered “heirloom,” a tomato must come from seeds that have a history of being passed down within a family or community (similar to the generational sharing of pieces of jewelry or furniture). Ideally — though not essentially — the tomato variety should date back to pre-1950, “because hybridization of tomatoes really kicked off in the ’50s,” Pauly explains. 

Hybrids are created when plant breeders intentionally cross-pollinate two different plant varieties to yield one containing the best traits of each of its parents. Heirloom tomatoes must be open-pollinated, meaning their flowers are fertilized by bees, moths, birds, bats, the wind, or rain. Of the 3,000 open-pollinated tomato varieties listed in the Seed Savers Exchange yearbook, only about a quarter, or 750, are true heirlooms, as founder Kent Whealy has told Fine Gardening. But Pauly says he wouldn’t be surprised if there are thousands of actual heirloom tomatoes in existence. 

“We only really know about commercialized varieties, and at some point in history, heirlooms were not commercially available,” he says. “So there are probably a lot that were saved by people who never commercialized them.”

And although Pauly is irked by “heirloom” as a marketing term for hybrid tomatoes that look the part, he says he has loosened his qualifications throughout the years. That’s because there aren’t any official regulations that govern heirloom tomatoes, meaning you might see a hybrid tomato labeled as “heirloom” at the store. 

How to source heirloom seeds

Pauly suggests starting regionally when sourcing heirloom seeds. “[There’s] a terroir to a really good-tasting tomato,” he says. “It’s not as broadcasted as grapes or wine, but tomatoes pick up the area they’re in.” 

In the Northeast, he often turns to High Mowing Organic Seeds in Wolcott, Vermont; Johnny’s Seeds in Winslow, Maine; and Fedco Seeds in Clinton, Maine. Nationally, he recommends TomatoFest in Little River, California, or the Seed Savers Exchange in Decorah, Iowa, which contains almost two dozen varieties. Crowdsourced favorites on the gardening subreddit include Baker Creek Heirloom Seeds in Mansfield, Missouri; Totally Tomatoes in Randolph, Wisconsin; and Victory Seed Co. in Irving, Texas. 

Pauly suggests starting with varieties you’ve eaten and enjoyed before — and always looking for flavor notes in the descriptions. He experiments with at least 10 new varieties each year, but some favorites he grows each summer include Great White, Black Cherry, Matt’s Wild Cherry, Jaune Flamme, and Aunt Ruby’s German Green.

How to grow heirloom tomatoes

When growing any tomatoes, airflow is critical so the plant can dry out between waterings, which helps stave off disease. As such, Pauly recommends planting a single tomato plant per large pot, or planting three to five stems in the ground using cages that are at least 2½  feet wide and four or five feet tall; he encourages the plants to grow upward by “taking off every side shoot and sucker,” he says. 

Pauly likes using broad-spectrum organic fertilizers, particularly fish and seaweed emulsions for the wealth of micronutrients they provide, and adds at least ¼ inch of compost to the soil every year. Most importantly, he says, plant more heirloom tomatoes than you think you’ll need, since they’re generally not super productive. 

“You might be discouraged by the amount of fruit you get, but the payoff is in that taste,” Pauly says. “Relish that it’s a moment in time and a brief season.”

How to use heirloom tomatoes 

When something is as naturally good as an heirloom tomato, it can feel almost criminal to cook it. “If I’m using heirlooms, I’m typically not cooking [them],” Pauly says. He prefers to keep it simple with an iconic caprese salad, alternating thick, horizontal tomato slabs with slices of mozzarella and just-picked basil leaves, sprinkling with sea salt, and drizzling with good olive oil and aged balsamic vinegar. 

The flavorful liquor of heirloom tomatoes also creates a beautiful no-cook tomato sauce, ideal for spooning over grilled fish or thick charred bread. Heirlooms are likewise the optimal choice when making a summertime BLT (and its numerous creative variations) or a gloriously simple tomato mayo sandwich on hefty bread. When Pauly faces an abundance of heirlooms, he’ll group them by color and blend them for gazpacho, the Spanish chilled tomato soup. He also likes to suspend some of the blended tomato pulp in cheesecloth over a bowl and catch the fresh tomato water, which offers a fantastic substitute for tomato juice in Bloody Marys. 

Then again, there’s nothing wrong with a few raw slices of tomato sprinkled with salt and drizzled with olive oil. We’ve waited the whole season for the real thing, after all. “When you cut that big horizontal slice and see the different undulations of fibers versus gelatin flesh…it just makes your mouth water,” says Pauly. “I could eat them like that all day long.”