How to Save Seeds

Updated September 2026 · Garden Advice Guide

Save seed only from open-pollinated or heirloom plants. Seed from an F1 hybrid will grow, and it will germinate perfectly well, but the offspring will not resemble the parent, and that surprise is the most common disappointment in seed saving. Check the packet before you save anything: if it says F1 or hybrid, skip it.

The rest is straightforward. Let the fruit or seed head mature past the eating stage, clean the seed by wet or dry processing depending on the crop, dry it hard, and store it cool, dark, and labeled with the year. Four crops make an easy start: tomatoes, beans, peas, and lettuce.

Planning next year's sowing already? Get timing and depth for every crop in our seed starting guide.

Open-Pollinated, Hybrid, and Heirloom

These three words get used loosely, and the difference decides whether seed saving works at all.

Open-pollinated (OP) means the variety breeds true. Pollinate a Brandywine tomato with another Brandywine and the seed grows Brandywine. The genetics are stable because the line has been selected over generations until it stopped varying. Every seed you can usefully save comes from an OP plant.

Hybrid, specifically F1, means the seed company deliberately crossed two different inbred parent lines. The resulting plant is uniform, often vigorous, and frequently disease resistant. That's the first generation, F1. But the genetics are a one-time combination, not a stable line. Save seed from that plant and you get the F2 generation, where the parent traits separate out again in every possible combination.

What F2 actually looks like in a garden: from one saved Sungold tomato, you might get some plants with small orange fruit, some with larger pale fruit, some with poor flavor, one or two that are fine, and a couple that revert to something closer to a wild currant tomato. They all grow. They're just not the thing you liked.

Heirloom is an OP variety with history, usually meaning it's been passed down for 50 years or more. Every heirloom is open-pollinated. Not every open-pollinated variety is an heirloom, since breeders release new OP varieties constantly. For seed saving purposes, heirloom and OP behave identically.

One more term worth knowing. Dehybridizing is deliberately growing out an F1's descendants for six to eight generations, selecting for the traits you want each year, until the line stabilizes into a new OP variety. It's a real practice and a genuinely fun long project. It is not what happens by accident when you save hybrid seed once.

Which Crops Are Easy, and Which Are Traps

The real variable is how a crop pollinates. Self-pollinating crops fertilize themselves inside a closed flower before it opens, so they stay true even with other varieties nearby. Cross-pollinating crops need pollen from another plant, carried by wind or insects, which means a different variety anywhere in the neighborhood can father your seed without you seeing it happen.

Squash is the classic trap, and it catches people every year. The genus Cucurbita contains four commonly grown species, and varieties within the same species cross freely. Most summer squash, zucchini, acorn squash, delicata, spaghetti squash, and pattypan are all Cucurbita pepo. So are most jack-o-lantern pumpkins and many ornamental gourds.

That means the zucchini and the acorn squash and the decorative gourd in the same garden all cross with each other. The fruit you eat this year is unaffected, because the fruit is the mother plant's tissue. The seed inside carries the cross, and next year you grow something with no name: often a hard, bland, oddly shaped squash with the worst of both parents. Ornamental gourds in the mix can also bring back high cucurbitacin levels, which are bitter and genuinely toxic in quantity, so never eat a bitter volunteer squash.

The practical way around all of this: grow only one variety per species if you want to save seed, or hand pollinate. Hand pollination on squash is easy. Tape a female flower shut the evening before it opens, tape a male shut too, open both in the morning, brush the male's pollen onto the female stigma, tape the female closed again, and tag it with string so you know which fruit to save. It is the same controlled cross that competition growers chasing record weights use to keep a seed line true.

Start with the four easy ones. Tomatoes, beans, peas, and lettuce are self-pollinating annuals that produce seed in the same season you plant them, need almost no isolation, and are cleaned with basic kitchen equipment. Get two seasons of those under your belt before taking on squash isolation or biennial carrots.

How to Save Seeds by Wet Processing

Wet processing is for seed embedded in damp flesh: tomatoes, cucumbers, melons, squash, and eggplant. The seed has to be separated from the pulp, and for tomatoes and cucumbers that means fermentation.

Why fermentation matters. A tomato seed is wrapped in a gelatinous sac. That coating contains germination inhibitors, which is the plant's way of stopping the seed from sprouting inside a fruit rotting on the ground. Dry the seed with the gel intact and you get a hard varnish that reduces and slows germination.

Fermentation solves that. A three-day ferment lets naturally occurring yeasts and bacteria digest the gel completely. It also does a second job that matters more than most people realize: the fermenting microbes suppress several seed-borne diseases, including bacterial canker, bacterial spot, and bacterial speck. Skipping the ferment means carrying those pathogens into next year's seedlings.

The process, for tomatoes:

1. Pick fruit that is fully ripe, ideally a touch past eating ripe, from a healthy plant you actually liked.
2. Cut across the equator and squeeze the seed and gel into a jar. Save the flesh for cooking.
3. Add a splash of water, maybe an equal volume. Do not add more than that, since a dilute ferment stalls.
4. Cover with a coffee filter or a piece of cloth and a rubber band. It will smell. Put it somewhere you won't mind that.
5. Leave at room temperature for 2 to 4 days. Stir once a day.
6. Stop when a layer of white or gray mold has formed on the surface and most seeds have sunk. That's the signal. Going much past this point starts germinating the seed in the jar, which ruins it.
7. Fill the jar with water and stir hard. Good seed sinks. Pulp, mold, and hollow seed float. Pour off the floaters. Repeat 3 or 4 times until the water runs clear.
8. Strain through a fine sieve, rinse well, and tip the seed onto a ceramic plate, a coffee filter, or a piece of window screen. Not paper towel, which the seed glues itself to.
9. Spread it into a single layer and stir daily.

Cucumbers use exactly the same method, with two changes: the fruit must be left on the vine until it turns yellow or orange and goes soft, which is far past eating stage, and the ferment usually runs 2 to 3 days.

Squash, melons, and eggplant do not need fermentation. Scoop the seed, rub it in a bowl of water to strip the fibers, skim the floaters, rinse, and dry. Squash seed should come from a fruit left to full maturity with a hard rind, and it improves if the whole fruit cures for another three to four weeks after picking.

Dry Processing for Beans, Peas, and Lettuce

Dry processing means the seed matures and dries on the plant, and your job is to collect and clean it. This is the easiest category by a wide margin.

Beans and peas. Pick a few of the best plants at the start of the season and flag them. Do not harvest pods from those plants. Let the pods stay on the vine until they're tan, papery, and rattle when you shake them, which is typically four to six weeks past the eating stage. Pull the whole plant and hang it in a dry sheltered place if frost or a long wet spell threatens before the pods finish.

Shell by hand for a small batch. For a big one, put the dry pods in a pillowcase and step on it, then winnow: pour the mix from one bowl to another in front of a fan, and the chaff blows away while the heavy seed drops. Discard any seed with small round holes, which are bean weevil exit holes. Freezing the finished seed for 48 hours kills weevil eggs before storage.

For growing notes on both crops, see how to grow peas.

Lettuce. This is the one that surprises people, because you have to let the plant bolt. A lettuce plant sends up a flower stalk 2 to 3 feet tall, opens small yellow flowers, and about 12 to 20 days after each flower opens the seed is ripe and carries a white fluffy pappus, like a tiny dandelion.

Lettuce ripens unevenly over two to three weeks, which is the whole challenge. Two approaches work. Either shake the stalk into a paper bag every couple of days and collect what's ready, or wait until roughly half the heads have gone fluffy and cut the entire stalk into a bag, then let it finish drying indoors for a week.

Rub the dried heads between your palms over a bowl to release the seed, then winnow the fluff away in front of a fan on low. Perfect cleaning is unnecessary. A little chaff in the jar does no harm as long as everything is bone dry. Our how to grow lettuce guide covers which varieties bolt early, which matters if you want seed from a slow-bolting type.

A note that applies to all three: save from several plants, not one. Six to twelve plants for beans and peas, and at least five or six lettuces, keeps enough genetic variation in the line that it doesn't weaken over the years.

Drying Seed Properly, and the Test for Dryness

This is where saved seed most often fails, and the failure is invisible until you open the jar in February and find mold.

Dry seed at room temperature, out of direct sun, with air moving around it. A fan on low across the room is ideal. Do not use an oven, a dehydrator above 95F, or a sunny windowsill, because heat above roughly 95F kills the embryo. Spread seed in a single layer and stir it daily so nothing stays damp underneath.

Allow one to two weeks for most seed, and up to three for large fleshy seed like squash or melon.

The tests for dryness, which are worth doing rather than guessing:

• Beans and peas: hit one with a hammer. Properly dry seed shatters. Damp seed squashes or dents.
• Corn: a dry kernel can't be dented with a thumbnail.
• Tomato, lettuce, pepper, and other small seed: bend one. Dry seed snaps or crumbles. Damp seed folds.
• Squash and melon seed: it should snap cleanly in half rather than bending.
• The general test: put a handful in a jar with a few grains of dry rice and seal it for a day. Any condensation on the glass means the seed is still too wet.

Seed stored above about 8 percent moisture molds, and even without visible mold, damp seed respires and burns through its stored energy far faster, so viability collapses within a year. If you're unsure, give it another week. Over-drying at room temperature is essentially impossible.

Storing Seed and How Long It Lasts

Three things kill stored seed: heat, moisture, and light. Cool, dark, dry, in that order of importance.

A sealed glass jar in the back of a cupboard on an interior wall is perfectly good. Add a silica gel packet or a tablespoon of dry powdered milk in a twist of paper to absorb residual moisture. A refrigerator extends life further, but only if the seed is genuinely dry and the container is airtight, since fridges are humid. Let a jar come fully to room temperature before opening it, or condensation forms on the cold seed.

Label with the year. Not the season, not "last year", the actual year, plus the variety and anything you noticed about the parent plant. Seed all looks the same in January.

Those numbers assume decent storage. Seed kept in a garage that hits 100F in August will underperform all of them. Seed kept in a sealed jar in a cool basement or a fridge routinely beats them.

Run a Germination Test Before You Rely on Old Seed

Sowing a whole bed with dead seed costs you two weeks in the best part of spring. A germination test costs ten minutes and a paper towel, and it tells you both whether the seed is alive and how thickly to sow.

1. Count out 10 seeds. Twenty gives you a better number if you have seed to spare.
2. Dampen a paper towel so it's wet but not dripping.
3. Lay the seeds on one half, spaced out, and fold the other half over.
4. Roll it loosely, put it in a zip bag or a lidded container, and leave a corner open for a little air.
5. Keep it somewhere warm, about 70F. On top of the fridge works.
6. Check every two days and re-dampen if needed. Do not let it dry out.
7. Count sprouts at the crop's normal germination time, then again a week later. Lettuce and radish report in 3 to 5 days, tomatoes 7 to 10, peppers 10 to 14, parsley up to 3 weeks.

Worked example. You find a jar of 2022 bean seed. You test 20 seeds and 13 sprout by day 8.

• Germination rate is 13 divided by 20, which is 65 percent.
• You want 30 plants in the row.
• Divide 30 by 0.65, which is 46. Sow 46 seeds to land on 30 plants.
• Add a small margin for field conditions, since a paper towel at a steady 70F is kinder than April soil. Sow 50.

The decision rule most gardeners use: above 80 percent, sow normally. Between 50 and 80 percent, sow proportionally thicker as above. Below 50 percent, the seed is usable but the seedlings that do come up are often weak, so replace it if you can. Below 25 percent, throw it out.

Sprouted seeds from the test can be potted up carefully if the crop transplants well, which turns the test into a small head start rather than a loss.

Biennials: Carrots and Beets Are a Two-Season Project

Some crops flower in their first year, and some don't. Annuals like tomatoes, beans, peas, and lettuce grow, flower, set seed, and die in one season, which is why they're the easy starting point.

Biennials grow a root and leaves in year one, need a cold period, and only flower and set seed in year two. Carrots, beets, chard, onions, parsnips, cabbage, kale, broccoli, celery, and turnips are all biennial for seed purposes.

That changes the job in three ways.

You have to overwinter the plant. In zone 6 and warmer, heavy mulch over the row often carries carrots and beets through. In colder zones, lift the roots in fall, store them in damp sand at 32F to 40F, and replant them in early spring. Onions overwinter as stored bulbs and get replanted the same way.

You give up the harvest. The carrot you save seed from is the carrot you don't eat, and it occupies bed space for a second full season while it throws a 4 foot flower stalk.

Isolation gets harder. Carrots cross with Queen Anne's lace, which grows wild along roadsides across most of the country, so genuine isolation means half a mile or a physical cage with introduced pollinators. Beets and chard are the same species and cross with each other, and their pollen travels a long way on the wind.

None of that makes biennial seed saving a bad idea, and there are lovely old carrot and beet varieties kept alive entirely by home gardeners doing it. Just go in knowing it's a two-year commitment with real isolation requirements, not a weekend job. Save your first biennial seed after you've done a few seasons of tomatoes and beans, and see how to grow tomatoes and how to grow beets for growing out strong parent plants in the first place.

FAQ

Can you save seeds from hybrid vegetables?

You can, and the seed will germinate, but the plants won't match the parent. An F1 hybrid combines two inbred lines, so its offspring separate out into every combination of the parent traits: different sizes, colors, flavors, and disease resistance from one packet of saved seed. Save from open-pollinated or heirloom varieties instead.

How do you know if a variety is open-pollinated?

The packet or catalog listing says so, usually as OP, open-pollinated, or heirloom. If it says F1 or hybrid, it isn't. Anything with no label at all is worth checking with the supplier, because most modern supermarket produce and many big-box transplants are hybrids.

Do you have to ferment tomato seeds?

For reliable results, yes. The gel sac around a tomato seed contains germination inhibitors, and drying seed with the gel on creates a varnish that slows and reduces germination. Fermentation also suppresses seed-borne bacterial diseases like canker, spot, and speck, which otherwise ride into next year's seedlings.

How long does it take to dry saved seeds?

One to two weeks at room temperature with air moving over them, and up to three weeks for large seed like squash and melon. Keep them out of direct sun and never use heat above about 95F, which kills the embryo. Test by bending small seed, which should snap rather than fold, and by hitting a bean with a hammer, which should shatter rather than dent.

Why did my saved squash seeds grow something strange?

Squash cross-pollinate freely within a species, and most zucchini, acorn squash, delicata, spaghetti squash, pattypan, and jack-o-lantern pumpkins are all the same species. Any two of those growing near each other will cross, so the seed produces an unnamed hybrid. Grow one variety per species, or hand pollinate and tag the fruit.

How long do saved seeds stay good?

It varies by crop. Onions, leeks, and parsnips are down to one year, beans and peas hold about three, brassicas four to five, and tomatoes, cucumbers, lettuce, and squash often five or six. Those numbers assume cool, dark, dry storage in a sealed jar. Run a germination test on anything past its expected life.

How do you test old seed before planting?

Roll 10 or 20 seeds in a damp paper towel, seal it loosely in a bag, and keep it around 70F. Count sprouts at the crop's normal germination time, then divide sprouts by seeds sown for your rate. Above 80 percent, sow normally; between 50 and 80 percent, divide your target plant count by the rate to work out how many to sow.

Can you save seeds from carrots and beets?

Yes, but both are biennial, so they only flower and set seed in their second year. You have to overwinter the roots, either mulched in the ground in mild zones or lifted and stored in damp sand, then replant in spring and give up the harvest. Isolation is demanding too, since carrots cross with wild Queen Anne's lace and beets cross with chard.

Updated September 2026