How to Save Heirloom Tomato Seeds

Food and Agriculture

Heirloom tomatoes at the Walnut Creek Farmers' market in California. John Morgan / CC BY 2.0

By Tracy Matsue Loeffelholz

Sometime during the spring, backyard food growers decide what kind of tomatoes to grow: heirlooms or hybrids. Hybrid varieties have had the benefit of genetic tinkering that allows for some cool traits. But these seeds must be purchased new each year from the companies that create them.


Heirloom varieties have long, stable genetic histories, and these seeds usually have been passed down for generations within communities. Heirloom vegetables are irresistible, not just for the poetry in the names, but because these titles stand for real stories. Vegetables acquire histories when they are saved as seeds for many generations, carefully maintained and passed by hand from one gardener to another, wrote author-turned-farmer Barbara Kingsolver in her memoir, Animal, Vegetable, Miracle (2007).

Most tomatoes in a supermarket are hybrids, bred for uniform shape, mechanized harvest and long journeys. A study by the U.S. Department of Agriculture found that between 1903 and 1983, the variety of produce being grown had shrunk by 93 percent—408 varieties of tomatoes down to 79—and many of those heirlooms have been lost entirely. Like sunshine, heirloom seeds are of little interest to capitalism if they can’t be patented or owned, Kingsolver wrote.

That has spurred backyard farmers and networks like Seed Savers Exchange to preserve what’s left. If you’re traveling to out-of-the-way farmers’ markets or find yourself dining on beautiful heirloom tomato varieties that you find particularly delicious, save a tomato slice to take home. Then save the seeds to grow your own. Here’s how:

1. Save a big tomato slice to take home.

2. Dig around to extract the seeds, surrounding pulpy gel, and juice, and put in a non-metal cup or jar.

3. Allow it to sit for two days at room temperature. Don’t be alarmed by a little mold. The fermentation kills viruses, sorts out dud seeds and separates seeds from their gel coating. Add water, stir, and wait for the mixture to settle. In general, the healthy seeds will sink to the bottom.

4. Pour off the goop, liquid and any floating seeds, then rinse the good seeds in a strainer.

5. Arrange the biggest, fattest seeds on a paper towel, and allow them to dry for a couple of weeks. When it’s time to plant, just pinch off pieces of paper towel. Don’t forget to check the Seed Saver’s Exchange to see if your variety is in its seed bank. If not, let them know what you’ve got.

Reposted with permission from our media associate YES! Magazine.

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