As growing season nears an end, some of us will need to harvest seeds for next year.
Old varieties or open pollinated crops grown in isolation are the best choice for saving seeds, as they produce true-to-type plants the following year.
Hybrids are not a good choice, because not all produce the same fruit — often having the traits of one or the other parent. The original seed envelope will tell you if the variety you’ve used is a hybrid.
Weston Miller, a horticulturist with Oregon State University Extension Service, suggests “If you choose the right types of vegetables, you can keep them going year after year without buying them again,” explaining that this is a great way to learn more about cultivated plants.
Annual fruits and herbs are among the easiest from which to collect the seeds. Care needs to be taken to collect seeds when they are brown and mature, or if enclosed in a fleshy fruit, when the fruit is very ripe or overripe. A healthy plant should be chosen for seed collection.
Beans or peas signal their readiness for collection when they have dry pods. Lettuce’s seed will turn brown and hard before harvest, pepper will be red and wrinkly.
Mature cucumbers and tomatoes require a bit of seed processing. Scooped seeds from the fleshy fruits need to rest in a bucket of water and be stirred daily; three days of the water bath for cucumbers and five for tomatoes. The fermentation process taking place in the water eliminates some of the pathogens. In the end, floating seeds and pulp need to be discarded, along with the water. The seeds that sink are the viable seeds and require drying spread on a paper towel in a cool place before storing.
As a rule, seeds need to be stored over winter in a cool, dark, dry place, preferably in an airtight container. A desiccant pouch or a few grains of rice can be used during storage. Freezer storage is also recommended as an additional pathogen inactivation step.
How Pollinators Determine Seeds
Since cucurbits (cucumbers, watermelon, zucchini) are insect pollinated, unless you are growing your plants in isolation, they may be crossing with your other variety or even with your neighbor’s cucurbits. As a result, a plant may bear a fruit that is not true-to-type, and at times, produce bitter tasting fruit. Tomatoes, which are mostly self-compatible, require no insect to pollinate and thus are mostly a safe bet for seed collection.
Plants from the brassica family, consisting of broccoli, cabbage, cauliflower, kohlrabi, Brussel sprouts, and the like, are insect pollinated. While seed collection of these bolted plants is easy, the polyamorous nature of those plants predestines them to outcrossing. Insects bringing pollen from various flowers to one receptive stigma maintain healthy diversity of the population.
Be aware, some brassicas are biannual, that means they require a cold period to produce seeds.
Beets and Swiss chard are among the plants that are wind pollinated. To obtain true-to-type seeds, plants need to be about half a mile apart.
A challenge with carrot seeds is its crossing with other carrot family members, such as Queen Ann’s Lace, a very common weed.
Each garden is a perpetual experiment. So despite the challenges, many gardeners do collect the seeds looking forward to the surprise crop next year.For more information on seed collection contact the extension service at https://catalog.extension.oregonstate.edu/pnw170.