Seed saving is one of the small joys of gardening: knowing that what you planted this year can continue for many years to come.
Couple that with the uncertainty of seeds being available when you need them (if you were caught in the mad dash for seeds last spring, like everybody else) and seed saving is more important than ever.
Now that we’re nearing the end of the season, my kitchen counter is lined with tea towels and saucers of all sizes, with seeds of all kinds spread out to dry. Even more fruits, vegetables, and seed pods are sitting in baskets or paper bags, waiting to be extracted, washed, dried, and stored.
It seems easier to just buy new seeds every year (uh, if they’re not sold out everywhere), and sure, seed packets don’t cost all that much.
But when you save seeds from your own garden, you’re preserving a piece of horticultural history — continuing the “bloodline” of your heirloom vegetables, fruits, flowers, and herbs to ensure they will exist another generation.
Saving seed and raising crops from them year after year also means your future plants will become more adapted to your climate and growing conditions, making them more vital, productive, and resistant to local diseases.
Selecting the right seeds to save
Open-pollinated vs. hybrid seeds
To assemble your own seed library, start with plants from self-pollinated heirlooms, or open-pollinated (OP) varieties.
Seeds from heirloom and OP varieties stay true to breed, so your next generation of plants will take on the same genetic traits of the plant they came from.
Seeds from hybrid plants, on the other hand, may take on the traits of just one parent, or even combine random traits of both parents to become a completely different plant from the one you previously grew.
Most supermarket produce comes from hybrids. While you can still save seeds from store-bought vegetables, it’s not ideal unless you don’t mind breeding something new in your garden. (And random crosses between plants do happen, even if they weren’t intentional — I’ll explain more below.)
Annual vs. biennial plants
Annuals are plants that go through one complete growing season before setting seed. They’re the most predictable, as you know the seeds will be ready for harvest within a few months of sowing.
Biennials, on the other hand, are plants that require two growing seasons to complete their life cycle. The first year, they focus their energy on vegetative growth. The second year, they reach sexual maturity and go into seed production.
Biennials can be trickier to collect seeds from, as you have to leave them in place for two years before they bolt. It’s not a big deal if you have the space, but in small gardens, it may not be worth it to dedicate a bed or two solely to growing seeds.
To make things more confusing…
Certain plants, such as tomatoes and peppers, are actually tender perennials (meaning they can survive year-round so long as frost doesn’t kill their roots), but they’re more commonly grown as annuals in most climates.
Other plants, such as fennel, celery, lettuce, spinach, and radishes, can behave as annuals or biennials, depending on the hardiness zone they’re grown in.
How to choose which plants to save seeds from
When saving seeds, you should collect from your most vigorous plants with the most desirable characteristics — those that germinated first, produced fruit the earliest, produced the most fruit, or bolted last.
You should also collect seeds from healthy vegetables that are ideally sized and shaped, and feature the strongest varietal characteristics (such as coloring, striping, or pleating unique to that strain).
By singling out these characteristics in your garden, you’re essentially doing the same thing plant scientists do in laboratories when trying to breed desirable traits into seed varieties.
Every time you grow that variety, and select seeds from the plants with the strongest traits again, you help those traits become more prominent in each subsequent generation.
Marking the perfect plant
If you grow many plants, it can be difficult to remember which vegetables to save seeds from, or which to allow to dry out on the vine.
Here’s a quick tip: Mark your specimen with string or tape so when the time comes to harvest its seeds, you know which vegetables to gather with just a quick glance.
Throughout the season, I walk around my garden looking for the perfect tomato (or bean, or pepper…) and wrap a ribbon around its stem.
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Not only does this little step make easy work of collecting the best seeds later on, it also keeps the kids (and curious friends) from unknowingly picking a prized fruit before its prime seed-saving time.
Self-pollinated vs. open-pollinated plants
Self-pollinated plants have both male (stamen) and female (pistil) parts on the flower and can produce fruit without outside pollination.
Legumes are a common example of self-pollinated plants, and thus are the easiest seeds to save as no special treatment is needed.
Open-pollinated plants rely on wind, insects, birds, or humans to spread pollen. Most plants are OP and will cross-pollinate with other plants of the same species.
When cross-pollination happens, the next generation of plants may bear similar characteristics to either parent, but actually be a new strain. In effect, a hybrid is created and will often produce sterile seed.
To prevent cross-pollination, you can try one of the following methods:
- Grow only one variety of an OP crop per season. (For example, grow red onions this year, and yellow onions next year if you want to collect seeds from them.)
- Isolate your crops with physical barriers (like greenhouses, row covers, or bags) that prevent pollen from blowing in the wind or pollinators from spreading pollen to nearby plants.
- Time plantings so that varieties of the same species are not flowering at the same time.
- Plant different varieties at substantial distance from each other. (This is usually out of the question for home gardeners whose neighbors also have gardens, as the required distances can be anywhere from a hundred feet to a mile or more, depending on the breed.)
Collecting and storing seeds
There are two ways to collect seeds:
- Wait for the seed pods or seedheads to dry out completely on the plant. Think: peas, beans, radishes, spinach, and parsley.
- Wait for the vegetable to over-ripen a bit on the plant to ensure the seeds are mature. Think: tomatoes, cucumbers, eggplants, peppers, and squash.
How to collect seeds from seedheads
With the first method, you want to gather the seeds when they have hardened and dried out, but before the seeds drop from the plant (as with flowering seedheads) or before the pods and capsules split open (as with legumes).
Collecting seeds from ornamental flowers is most efficient when you’re deadheading spent blooms, as they’re easy to miss if you wait too long before they fall.
If you’re collecting seeds from vegetables, you simply have to wait until the end of the season when they bolt or become past their prime.
To extract tiny seeds (like those that come from cilantro, basil, lettuce, or mustards), wait for the flower petals to start fading and dropping from the plant (a sign that the seeds are almost ready for harvest).
At that point, cut the seedhead and place it inside a brown paper bag (or a bag made from any breathable material like linen or muslin) so it can finish drying indoors at room temperature.
After a week, give the bag a shake to release any seeds that haven’t fallen off naturally, and separate the seeds from the dead stems and petals.
Once fully dried, these seeds can be stored right away.
If you live in a humid climate or received rain before collecting the seeds, let them air dry indoors for a few days before storing.
How to collect seeds from mature vegetables
The second method of saving seeds requires you to wait until the seeds are mature.
How can you tell if they’ve matured?
- The fruit (vegetable) is fully ripe, even a bit over-ripe. Look for color changes (like peppers that have turned red), wrinkling, or sunken or softening flesh.
- The leaves are starting to brown and die, indicating the plant has done its job of reproducing for the next cycle.
Once you’ve harvested the vegetable, scoop the seeds out and wash off any pulp clinging to the seeds. I usually run water over them in a fine mesh sieve and rub them gently against the mesh to remove any fleshy remnants.
Once the seeds are cleaned, spread them out on paper towels or tea towels to absorb most of the moisture, then transfer them to a non-porous surface (like a metal sheet pan or ceramic dish) to finish drying. A non-paper surface keeps the seeds from sticking and picking up lint.
Every day or so, stir them around to make sure all the surfaces dry evenly.
Storing seeds for maximum shelf life
Seeds must be thoroughly dry before storing, otherwise mold or mildew can set in. Thicker seeds (such as squash) may need to dry out for at least a week before being stored.
I like to stash my seeds in paper coin envelopes to save space, but you can also use small baggies, spice jars, tea tins, pill boxes, medicine bottles, old film canisters, or any other container you find around the house.
Label the container immediately with the plant name and date of harvest — it sounds obvious, but I’ve saved my fair share of “Grab Bag Tomatoes” over the years when I collected different varieties of tomato seeds at the same time, and got them all mixed up.
I keep all my seed envelopes in military ammo boxes, and store them in a closet on the north side of the house. It’s usually several degrees cooler in there than the rest of the house.
If you have the space, storing seeds in airtight containers in the fridge is also a great option, but any cool, dark, and dry place will work. Heat and humidity are the enemies.
The optimal environment for storing seeds is below 40°F with less than 10 percent humidity, inside airtight containers in a dark environment.
Seeds are most viable when sowed within the first year or two of saving, but if properly dried and stored under ideal conditions, can last several years. (Download my handy cheat sheet to help you figure out how long your seeds will last.)
If you start saving seeds now from all your favorite plants, you may never have to buy seeds again. And homegrown seeds make thoughtful little gifts!
Worth a read: Delightful Stocking Stuffers for Gardeners (Under $25!)
After all, it was the tradition of saving and sharing seeds with families, friends, and that old farmer down the road that kept heirlooms alive for so many generations.
Learn more: The Stories Behind Heirloom Seeds
Seed Saving Sources
LaRibbons Solid Color Satin Ribbon | Fiskars Multi-Snip with Sheath | OXO Good Grips Fine Mesh Strainer | Soligt Self-Sealing Seed Packet Envelopes | Peony Man Self-Adhesive Seed Envelopes | Redneck Convent Metal Ammo Case | Robert E. Gough The Complete Guide to Saving Seeds | Suzanne Ashworth Seed to Seed
This post updated from an article that originally appeared on September 10, 2011.