When we think of heirlooms, most of us think of jewelry, photographs and other antiquities that speak to our heritage. If you’re a gardener, however, chances are that the word “heirloom” conjures up rows of colorful tomato plants, pole beans and peppers.

Within the past decade, home horticulturalists have embraced the widespread trend to cultivate heirloom vegetables in their gardens. Although there is some disagreement about the exact criteria for a vegetable to be classified as “heirloom,” most gardening experts agree that the plant must be a decades-old variety that owes its survival to culling and cultivation by private gardeners, rather than commercial seed growers and companies.

According to Eve Reshetnik Brawner, who co-owns Boulder-based Harlequin’s Gardens with her husband Mikal Brawner, heirloom vegetable seeds have been swapped and cherished for centuries, from America’s days as an agrarian society through the years of World War II “victory gardens.”

“Heirlooms come from a time when people were very connected to and growing at least some of their own food,” she said. “Some Southwest native varieties of beans, squash and corn have been grown and saved for thousands of years. But heirloom plants can also include old commercial varieties that were dropped by the seed companies and saved by home gardeners — such as the Rutgers tomato, which was developed in the 1930s by Campbell’s Soup.”

Modern vegetable varieties are cultivated for the convenience of market suppliers in terms of mechanical harvesting, shipping and storage, Reshetnik Brawner said. This same approach applies toward many mass-marketed seed varieties, which are also cultivated for their uniformity of appearance, size and ripening time.

Heirloom gardeners feel that this emphasis on convenience and uniformity is responsible for a vastly inferior product on grocery produce shelves. Horticulturists such as Reshetnik Brawner believe heirloom vegetables have not only a superior flavor, but an improved nutritional content as well.

Unlike hybrid plants, which are dependent on seed pollination and need to be recreated every generation, heirloom plants are “open pollinated”: Their seeds will produce plants of the same variety as the parent plant.

For many heirloom gardeners, seed saving is another important part of the cultivation process. Rather than purchasing new plants, many enthusiasts prefer to cull the seeds from the present harvest for replanting. This is one reason tomatoes are so popular; heirloom tomato seeds can be easily saved without sacrificing the plant or its harvest.

“By saving seeds, you’re participating in an ancient ritual that connects you with your ancestors,” Reshetnik Brawner said. “It can be a profound experience.”

Since 1975, the Seed Savers Exchange, a nationwide, nonprofit organization, has been a source for heirloom vegetable and flower seeds. In recent years, Internet sources and forums for heirloom enthusiasts have also flourished.

As executive director of Growing Gardens of Boulder, Ramona Clark has seen a growing local trend for cultivating heirloom vegetables. She attributes much of this interest to the developing market for high quality, locally sourced food.

“Heirloom tomatoes offer that special flavor that people want when they think of a home-grown tomato,” said Clark. “If you’re going to spend all that time and energy to grow a tomato, it might as well be something you can’t find in a store.”

Many of the heirloom tomato varieties that originated in Siberia and other parts of Russia have adapted well to the Colorado climate, Clark said. Her favorites for this area are Black Krim, Cherokee Purple and Mortgage Lifter, which has an amusing story behind its name.

“The man that developed the Mortgage Lifter had a car radiator repair shop,” Clark said, “and he sold so many of these tomatoes, he was able to pay off his mortgage.”

Most heirloom vegetable varieties are as easy to grow as standard types, but because of Colorado’s low humidity, cool nights and short growing season, the experts agree that it’s best to choose plants that need only a short growing season and mature early.

There are, however, other tolerance factors that home growers should also consider.

“A lot of modern-day tomatoes are bred to resist certain disease, but heirlooms are not,” Clark said. “You have to make sure the plant is healthy and solid. The healthier it is, the less susceptible it is to these problems. You also need good, rich soil and eight hours a day of direct sunlight — as hot as possible.”

Additionally, some modern vegetable varieties are bred to repel pests, but heirlooms don’t have this built-in protection. Clark recommends putting in pest-deterrent plants — such as marigolds — around your crop of heirloom vegetables to protect them from unwelcome visitors.

For novice heirloom gardeners, Clark said, a variety of reputable seed retailers specialize in heirloom varieties. It’s most important, she added, to determine the right growing conditions for your plants, and then continue to pay attention to them throughout their growing season.

“Gardens and plants are like children,” she said. “You have to take care of them if you want something you’re going to be proud of at the end of the road.”