Every year, Rosalie Shepherd's father used to gather the seeds from tomatoes he grew and replant them. The following year, the tomato plants would yield bigger and juicier tomatoes until some of them grew to weigh two to three pounds.
Since becoming a Palo Alto master gardener 16 years ago, Shepherd has saved a variety of fruits and vegetables seeds, following in her father's footsteps.
"There's a certain satisfaction in saving your seeds and knowing that you've improved the seed," she said.
After plants grow and ripen, gardeners will often save seeds for replanting — doing so saves money and helps sustain crop diversity, which gives future plants traits to keep them healthy and strong.
Shepherd emphasized a sobering statistic, but offered some hope: Since 1900, 97 percent of vegetable and fruit varieties previously available in the U.S. have been lost, so it's more important than ever to save the seeds of the best heirloom plants for future generations.
Want to start saving your own seeds? Master gardeners say it's easy.
There are three types of seeds: hybrid, open-pollinated and heirloom. Hybrids are created when two different varieties of a plant cross-pollinate, creating something different from the "mother" variety. Sheperd said hybrids may not produce desirable harvests since "you won't know what you'll get."
She said the best kinds of seeds to save are from open-pollinated plants, which rely on self-pollination or natural pollination by insects or wind. Open-pollinated seeds ensure that the plant will produce the same crops. Heirloom seeds, which are open-pollinated, are passed down through generations and saved for specific traits.
The two primary methods for seed saving are "wet seed" and "dry seed" methods. Wet seeds are harvested in plants that hold their seeds in the fruit. Dry seeds are harvested after the seeds have dried on the plant.
The top five easiest seeds to save are peas, tomatoes, lettuce, beans and peppers, according to the University of California. Shepherd suggests beginning with tomatoes. Because tomatoes rarely cross-pollinate, separating varieties of the plant is less important. Still, she recommends blocking off a section of the garden for seed-saving plants so that there is less chance of cross-pollination.
Make sure you know when the seeds have matured, said Shepherd's colleague, Candace Simpson, a master gardener and Palo Alto resident.
"If you collect them too early, they may not germinate or they may germinate poorly," she said. "So the embryo in that seed has to mature."
Hillie Salo, another master gardener, encourages all gardeners to try their hand at seed saving. Though each person may only have one "little packet of seeds," she said, when they save those seeds, they are able to contribute to a larger gene pool through the seed-saving community, which maintains local seed libraries, holds seed exchanges and puts people in touch with seeds not readily available to their geographic location. Salo has been involved in many of these seed-saving initiatives and currently participates in Silicon Valley Grows: One Seed, One Community.
Preserving plant variety also serves as a hedge against climate change, said Simpson, who is a member of Seedsavers Exchange, a national nonprofit organization dedicated to preserving varieties of plants through seed saving.
"What if it gets wetter somewhere?" she said. "There are certain species of food plants that don't do well in that wetter environment. It's important that we save some that do do well in that wetter environment so we can switch to those."
Besides, she said, it's exciting to see what each crop brings. The Palo Alto tomato, for example, was a tomato Simpson bought under a mislabel. Because she didn't know the original name for the tomato, once she began sharing its seed with the community, she named it the Palo Alto tomato.
"Now, there are people all over the area growing the Palo Alto tomato because we started selling it at our tomato sale," she said. "A new variety was born, and it's fun to know that."
How to save seeds
Saving tomato seeds uses the "wet-seed" method, which requires fermentation after the tomatoes have ripened. Let the plant mature for a few days, or even weeks, after the fruit first reaches edibility; this allows the seeds to increase in size and quality.
1. Once the fruits have fully matured, select five to 10 of the healthiest tomatoes in your garden — look for large, blemish-free tomatoes that have strong, fresh flavor. Scoop the seed masses out of the fruit and soak the seeds and pulp in a container of water until the pulp is easier to separate from the seed, which is usually no more than eight to 12 hours.
2. To ferment, put the pulp and seeds into a small jar or glass and add a little bit of water if necessary. Cover the container and place it in a warm place, with temperatures between 60 to 75 degrees. Wait three days, stirring once a day, and soon a layer of fungus will float to the top of the mixture. The good seeds will remain at the bottom of the container.
3. After three days, fill the container with warm water. After the contents have settled, start pouring out the water along with the pulp and immature seeds, which will float to the top along with the fungus. Repeat until the water being poured out has become almost clear and the remaining seeds line the bottom of the container.
4. Collect the seeds, making sure they are clean from any mold or tomato particles. Dry the seeds in a single layer on a paper towel, paper plate or strainer with holes smaller than the seeds. When dry, store the seeds in an envelope or airtight container labeled with the date and variety, and keep them in a cool and dry area. Do not save seeds in plastic bags.
The "dry seed" method follows fewer steps, but different plants will hold seeds in different places. Plants in which the seed is the edible part of the plant, such as corn, wheat and beans, usually hold their seeds for some time after maturing.
1. Cut and stack these plants in a dry place to cure and dry before removing the seeds. Plants in which the unripe seeds hang on while the matured seed is falling off, such as lettuce, onions and cabbage, will require collection of the ripe seeds in a paper bag on a daily basis.
2. After you've allowed the seeds to dry and mature for as long as possible on the plant, strip the seeds into a bucket and loosen the seeds from the rest of the plant material by stomping on top of the seed and chaff or rubbing the plant over a hard surface or by hand.
3. To fully dry off the seeds, spread them on a screen in a single layer in a well-ventilated, dry place. As the seeds dry, the chaff and pod can be removed or blown away. The heavier seeds — the good seeds— will remain.
Follow the same steps for storing.