What is an Heirloom Plant?

You probably use the word heirloom when talking about great-grandma’s quilt or some other treasure passed down in your family from generation to generation. Plants are the same.


When you hear the word heirloom, think old, precious, rare.


An oft-heard story goes like this: “Great-grandma, Rita, grew these tomatoes in her garden all of her life. Her mother gave them to her and showed her how to grow them. They’ve been in the family for generations.”

In addition to being old, heirloom seeds are also open-pollinated. This means that Rita’s tomatoes can be planted in her garden, the seeds gathered from the ripe fruit, and next year’s crop, grown from that resulting seed, will produce a plant that looks like the parents.

Most seeds purchased from local garden stores are not open-pollinated, but hybrid. To make them, two separate varieties of tomatoes are cross-pollinated. The seed saved from the ripe fruit of this plant will not reliably produce plants similar to the parent in an ongoing fashion.

I spend a lot of time talking to the public about gardens, and the same question always surfaces.


“Do heirloom plants grow better or worse than hybrids purchased from the local garden center?”


That depends.

Where was Rita’s tomato grown? If the answer is in Iowa, then her heirloom will probably have a difficult time adjusting to our hot, dry Arizona climate.

Heirloom plants have been grown in the same environment for many years and have acclimated to local conditions: rain, temperature, soil, sunshine. In their home surroundings, they thrive. If transferred to a different area, they may flounder.

When sowing an heirloom vegetable garden, look for those plants that have been grown locally, under the same conditions in which they will be planted.

In Arizona, this often means using the seeds saved by the local native people. The Tohono O’odham, for example, have preserved a precious heirloom onion, called an I’itoi. Pronounced “e-etoy,” its name means “Elder Brother,” creator to its people.

The little onion was brought to Arizona by a Jesuit missionary, Father Kino, in the late 1600’s, who gave it to the tribe as a gift. They planted it on their sacred Baboquivari Mountain, which is the only place where it remains wild.

For hundreds of years, the onion has been growing and adapting to our dry climate and alkaline soil. To escape the hot summers, the little guy dries up and goes dormant, reemerging with fresh green stalks in the fall to grow throughout the mild desert winter. In my garden, the I’itoi onion is hardy and almost indestructible.

As this plant was introduced by Father Kino, it is not native to Arizona. However, it has been growing here for hundreds of years and is considered a local heirloom. Rita’s tomato is the same. Perhaps she immigrated here from Russia in the early 1800’s and brought the seeds with her. Once they have grown in local conditions for at least 50 years, the tomato can be considered a local heirloom.

Back to the question…


“Do heirloom plants grow better or worse than hybrids purchased from the local garden center?


That depends.

Has the plant grown in the local area long enough to be acclimated to the surrounding climate and soil conditions?

If I want to grow Rita’s tomato in Arizona, the answer is no, and results are doubtful. The plant may or may not perform well. Constant and loving care from the gardener may overcome inherent problems to produce a bumper crop—or not.

This is why garden centers sell hybrid plants that have been developed to produce in a wide variety of conditions and localities.

What if the heirloom plant has been locally grown? The Tohono O’odham I’itoi onion, for example, is a tough guy if it produces in the desert southwest, which is where it’s needed most.

In Arizona, for example, the population is booming. Farmland pushes out onto land with marginal growing conditions (hot and dry). To provide irrigation, underground pumps pull precious ground water from the aquifer, depleting the supply. Sometimes the porous layers of earth collapse and compact, unable to hold liquid again.

Farmers need local heirloom crops, like the Tohono O’odham onion, which is adapted to challenging desert growing conditions and requires less irrigation.

The next time you sow an heirloom garden, ask yourself…


“Do heirloom plants grow better or worse than hybrids purchased from the local garden center?”


And remember the correct answer.

That depends.

And then select varieties right for your area.

If you are like me, discovering the answer may draw you into learning about how the plants were historically grown, harvested, and used along with the culture and traditions of the people who nurtured and preserved them.


Learn more about the Tohono O’odham I’itoi onion.

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