Editor’s Note: This article has been updated.
There was a time when I fought my garden’s natural tendency to make seed. Planting and tending is hard work, and prolonging the harvest seemed only natural when my main goal was to grow as many vegetables as possible. Unfortunately, my garden had other ideas.
Every spring things in my garden would start out beautifully. Hunkered down in their beds, spinach leaves would unfurl in lush rows. Broccoli crowns would rise full and green. Somewhere nearby, cilantro would party with wild abandon between rows of carrots and beets.
Everything would be nearly perfect, when out of the sky the sun would blaze, triggering the broccoli to crane its skinny neck and festoon itself in tepid yellow blossoms. Suddenly my lettuces and arugula would join the race, oozing milky bitterness into the salad bowl each time I failed to admit their time had come.
Everything would be nearly perfect, when out of the sky the sun would blaze, triggering the broccoli to crane its skinny neck and festoon itself in tepid yellow blossoms.
One year I realized that fighting my garden’s drive to complete its life cycle was not only ridiculous, it was impossible. Most plants can’t resist the urge to make seed. Although we can encourage them to produce as long as possible, the inevitable will occur whether we like it or not.
But this inevitable phase of plant-hood is a gift for gardeners who want to propagate their own plants. In addition to costing less, seed saving provides a blend of regionalized plant varieties self-selected for their unique qualities. The seed stage of plant life also comes with its own show, depending on the plant, which is more than worth dedicating some small garden space.
Know the different seed types
To save seed, one is working with the garden rather than against it, collecting what nature is driven to create as the seasons change. There are different levels of effort required in seed saving, however, and not everything you collect will grow into the same sort of plant it came from.
Here’s what you need to know to increase the odds of getting the plants you want year after year.
These plants offer the easiest seeds to save. They usually pollinate themselves because the flowers they produce contain both male and female parts. They don’t need bugs or humans to help them reproduce, and they won’t usually cross-pollinate, which means you don’t have to separate your plants to ensure true seed.
There are exceptions to every rule, of course, and sometimes an insect will transfer the pollen of one plant to another, causing cross-pollination, but that outcome is less likely with these plants. Self-pollinating annuals set their seed during the same year you plant them and grow quickly to mature before frost. Some common self-pollinating annuals include:
Annuals that readily cross-pollinate
Slightly more difficult than self-pollinating annuals, you must physically separate annuals that readily cross pollinate if you want true seed. If you’re not concerned about seed purity, you can grow some of these vegetables close together and ignore the outcome.
Herbs like cilantro and basil will cross-pollinate with members of the same family, but for the most part, the differences in flavor aren’t that noticeable.
Squash will readily cross-pollinate with some others in the Cucurbitaceae family and will often produce less desirable cultivars with tough skins and bland flesh. Options for keeping squash seeds true include separating the plants to recommended distances, covering blossoms and pollinating them manually when the time is right, or growing distinct varieties that don’t cross-pollinate. Some distinct groupings include:
- Zucchini (Cucurbita pepo)
- Acorn squash and butternut squash (Cucurbita moschata)
- Watermelon (Citrullus vulgaris)
- Cucumber (Cucumis sativus)
Biennials are plants that take more than one season to produce seed. Biennials are generally more challenging for seed savers because the plants must survive the winter in order to complete a life cycle.
If you live in an area where temperatures plunge, you may need to mulch heavily or bring your plants indoors to protect the year-old plants, before replanting outside come springtime.
Good biennial candidates for seed saving include members of brassica oleracea, particularly kale, which is cold hardy and can sustain low winter temperatures. Carrots are one of the more challenging biennials to save for seed because of the likelihood that domestic plants will cross-pollinate with members of the wild carrot family (like Queen Anne’s lace, which is widespread). Other biennials include beets, parsley, parsnip, leek and celery.
Although not true seeds, seed potatoes, sunchokes and garlic cloves (to name a few) produce vigorous offspring with the same traits as the parent plant. These “seeds” are actually clones of a single parent plant whose genetic material remains the same from one generation to the next. You can grow these vegetables from the plant’s true seed, but saving the clones is usually easier in the short-term. (In the long term, some enthusiasts feel clone-grown potatoes encourage disease.)
Hybrid vs. heirloom seeds: which is best for seed-saving?
Within each vegetable family there are a myriad of seed varieties. Hybrid varieties are produced by crossing two different parent plants selected to maximize the benefits of both. Often hybrid vegetables are bred for disease resistance, higher yields, and/or vigor. However, seed savers beware: when you save hybrid seed, you may not get a plant that resembles what you started with. This is because other traits (possibly undesirable ones) from the original parents may dominate the next generation, leaving you with an unpredictable harvest.
Heirloom varieties, on the other hand, have been passed down for many generations and have stable traits. They are all open pollinated (which means they retain their characteristics when pollinated by any plant of the same variety). Some would argue they also taste better, because nutrients and flavor haven’t been compromised in the quest for productivity.
Heirloom vegetables are also more genetically diverse and tend to adapt to local growing conditions if permitted to grow for many generations in one location. If you save your own seed over many years, you can gradually select the plants that perform the best in your garden, eliminating those that fail to thrive. By saving seed, you are—in essence—designing seeds specifically for your garden.
Tips for harvesting and saving seed
When gathering the plant seeds, allow any pods to dry out and turn brown before cutting down and storing in a cool, dry place. Always harvest seed when conditions are dry (or as dry as possible).
- Peas and Beans: Peas and beans will rattle inside the pods when they are ready for harvesting and will continue to dry after removal from the garden.
- Brassicas: Kale, broccoli, and other plants in this family will rattle in their pods for a day or two before exploding and broadcasting their seeds all over your garden. Watch carefully leading up to maturation. Cut plants as soon as the pods begin to dry out and store on newspaper or in paper bags. They will continue to ripen and you won’t risk losing the seeds in the process.
- Tomatoes: To harvest wet seeds like tomatoes, pull seeds from the flesh and soak in water to remove gel and vegetable fiber. Soak 3-5 days, or until seeds sink to the bottom while the mixture ferments. Spread to dry on newspapers or another semi-absorbent surface and leave until dry.
- Squash: Pull seeds from flesh and soak in water for 1-2 days. Remove squash seeds from the water and lay on wax paper or newspaper for drying, checking frequently to see if they need turning.
- Lettuce: Gather lettuce seed when about one third of the plant has transitioned to a soft, fluffy seed-head. Clip and invert over a paper bag, rubbing the seed between your fingers or knocking against the bag to release the seed. Other seeds like peppers can be easily removed by separating the seed from the flesh and drying as above.
The key to long lasting seeds is good storage. Seeds must be dry when they enter storage or mold will shorten their lifespan. Keep dried seeds in a cool place free from moisture and humidity. If completely dry, seal in jars or any lidded containers that will keep moisture out.
It’s a good idea to check your seeds periodically throughout the storage period to ensure they remain dry and secure. If stored properly, seeds will last many years (depending on the variety) and you will have both an inexpensive and secure seed source for your garden well into the future.
Editor’s note: This article has been updated.