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Slice the top off your tomato to reveal the seeds. Squeeze seeds from the tomato into a bowl or jar. Add an equal amount of plain water.
Photo by S. Cory Tanner
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Cover with a breathable material (such as a paper towel) to prevent insects from getting in, and let it sit for 48 to 72 hours.
Photo by S. Cory Tanner
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The tomato pulp will ferment, separate from the seeds and float to the surface. The clean seeds will sink to the bottom.
Photo by S. Cory Tanner
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Rinse with clean water. Strain water and pulp from the seeds.
Photo by S. Cory Tanner
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Clean well to remove any remaining pulp. Seeds should be clean and free of pulp. Spread on a paper towel to dry.
Photo by S. Cory Tanner
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Air dry in a cool, dry location, out of direct sunlight, until completely dry. Make sure you label your seeds through the process to prevent mix-ups.
Photo by S. Cory Tanner
Heirloom vegetables, with their intricate flavors, colors and shapes, are wildly popular. Seeds saved from heirlooms, unlike hybrid varieties, produce crops similar, if not identical, to the original.
Seed saving makes economic sense, too. You don’t have to purchase new seed each year, and you can keep your favorites, regardless of what’s available for purchase.
I once bought seeds of an heirloom pepper called Georgia White from a local seed company. Assuming I could buy more, I didn’t bother saving seed. Later, when I tried to buy new seeds, no one had it—even the local company had lost its supply. This story has a happy ending thanks to my frugal grandfather, who saved some Georgia White seed deep in his freezer. Without those saved seeds, the variety may have gone extinct. It happens all the time.
Saving seed from your homegrown heirlooms is fairly simple. Don’t bother saving seed from hybrid varieties or grocerystore produce. Hybrids typically won’t produce true to type; their seeds will likely give you something different from the original. Unless you know the origin of purchased produce, it’s best not to save seed—you won’t know whether it’s a hybrid, and you run the risk of introducing a new disease into your garden.
In the garden, take care to prevent cross-pollination from wind or bees. It’s best to plant only one variety of a crop at a time. And resist the temptation to eat the biggest, best-looking tomato in your garden. That specimen may carry the best genes and should be saved for seed.
The easiest plants for saving seeds are those whose seeds are in pods or husks that dry on the plant (okra, beans, peppers). Just leave them on the plant until dry but before the pods split. Then harvest the pods and let them finish drying in a cool, dry location. Once completely dry, break the pods apart to release the seeds, and clean away the chaff by sifting, shaking or winnowing.
Seeds of fleshy fruits like tomatoes and cucumbers are coated in a gelatinous sac that must come off before drying. The best way to do this is by fermenting away the pulp. Cut the top off of a fully ripe tomato, and squeeze the pulp and seed into a jar. Cover the seeds with about an inch of water and set aside, out of direct sunlight. The pulp will ferment and separate from the seeds, which will settle to the bottom. Mold that forms on the water’s surface is completely normal and not harmful. Once pulp and seeds are separated, in about 48 to 72 hours, pour off the mold and pulp and rinse the seeds well. Strain, then spread on a paper towel to dry at room temperature.
For cucumbers and squash, let the fruit mature on the vine well beyond the point of edibility, until they are large and yellowed and their seeds have hardened. Harvest, cut in half, and scrape seeds out with a spoon. You can ferment cucumber pulp and seeds just like tomatoes. For squash, washing the seed is usually sufficient to remove any pulp.
Keep all of your seeds separated by variety in well-labeled, sealed containers, stored in a cool, dry and dark place. The refrigerator works great; the freezer is even better.
The biggest enemy to stored seeds is moisture. Store them with a desiccant, such as powdered milk. I save the little desiccant packets that come with packaged electronics and shoes and throw a few in my seed boxes to keep moisture down. Seeds stored this way may stay viable for two to five years, sometimes longer.
For more vegetable seed-saving techniques, read Clemson Extension's fact sheet HGIC 1255 on heirloom vegetables here.
S. Cory Tanner is an area horticulture agent and Master Gardener coordinator for Clemson Extension based in Greenville County. If you have any questions or comments, you can email him here.