Seed saving is one of the little joys of gardening. 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. Still more fruits, vegetables, and seed pods are sitting in baskets or paper bags, waiting to be extracted, washed, dried, and stored.
It would likely be easier to just buy new seeds every year, 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 your own seeds also means your future crops will be more adapted to your climate and growing conditions, and thus be more vital and productive.
Selecting Seeds to Save
To start 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 vegetables come from hybrids. While you can still save seeds from certain hybrids, it’s not ideal unless you’re looking to breed something new in your garden.
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).
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. A quick tip is to mark your specimen with string or tape so when the time comes to harvest its seeds, you can quickly gather all those vegetables 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. Not only does this little step make easy work of collecting the best seeds later on, it also keeps the Mr. (and wandering friends) from unknowingly picking a prized fruit before its prime seed-saving time.
Self-Pollination vs. Open-Pollination
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 preparations are 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, cages, row covers, or bags).
- 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 with gardening neighbors, as the 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 to dry out completely on the plant (peas, beans, spinach, parsley, etc.).
- Wait for the vegetable to over-ripen a bit on the plant (cucumbers, eggplants, peppers, squash, etc.).
With the first method, you collect the seeds when they have hardened and dried out, but before the pods split open (as with legumes) or before the seeds drop from the plant (as with flowering seed heads). 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.
With the second method, scoop the seeds out of the vegetable and wash off any pulp clinging on 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 to absorb most of the moisture, then transfer them to a non-porous surface (such as glass or ceramic) 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.
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” before when I was collecting 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 on a shelf in the closet. 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.
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. (Here’s a handy cheat sheet to estimate the lifespan of common vegetable, herb, and flower seeds.)
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! 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.
This post updated from an article that originally appeared on September 10, 2011.