Seed saving is the practice of collecting seed from your own garden, drying it, storing it, and sowing it next year. It saves money, preserves varieties you love — including varieties you cannot buy — and gives you plants already adapted to your garden. It is also satisfying: a tomato you grew from seed you saved yourself is a small act of independence. But seed saving has rules: not every plant saves true to type, not every seed stores well, and a few simple mistakes can leave you with seed that does not germinate. This guide covers which plants save well, how to collect, dry and store seed, and how to keep saved seed viable.
The most important idea in seed saving is the difference between open-pollinated plants and hybrids. Open-pollinated plants — including most heirloom varieties — breed true: seed saved from them grows into plants like the parent, provided they have not crossed with another variety. Hybrids, usually labelled F1, do not breed true: seed saved from a hybrid grows into plants that vary, and most will not be like the parent. So the first rule is to save seed only from open-pollinated varieties, and to check the packet or catalogue before you buy: it should say open-pollinated or heirloom. Our heirloom seeds guide explains heirloom varieties in detail. The second rule is to save seed from healthy, vigorous plants, not from the weakest ones — you are selecting the next generation, so choose the best. If you are unsure which varieties save true in your area, check your local extension service for local advice.
Which plants save true
Some plants are easy to save seed from, and some are hard. Easy plants are those that mostly pollinate themselves and do not cross readily: tomatoes, beans, peas, lettuce and peppers are all good for beginners. Tomatoes are self-pollinating, so saved seed usually comes true unless another variety is growing very close. Beans and peas are also self-pollinating and their seed is large, easy to collect and easy to store. Lettuce is self-pollinating too, though it needs to bolt and flower before it sets seed. Harder plants are those that cross-pollinate freely: squash, pumpkins, cucumbers, corn, carrots, brassicas and beets all cross with other varieties of the same species, so saved seed may produce plants unlike the parent unless varieties are isolated by distance or by hand-pollination. For beginners, start with tomatoes, beans, peas and lettuce, and leave the cross-pollinators until you have more experience. Always label saved seed with the variety, the date and where it grew, because unlabeled seed is useless.
Collecting seed
Let the seed ripen fully on the plant before collecting it — seed collected too early may not germinate. For dry seed such as beans, peas, lettuce and most flowers, let the pods or seed heads dry on the plant until they are brown and rattling, then collect them on a dry day and bring them indoors. For wet seed such as tomatoes and cucumbers, scoop the seed out of ripe fruit: tomato seed needs fermenting — put the seed and pulp in a jar with a little water, leave it for two to three days until a mould forms on top, then rinse the seed clean in a sieve. Fermenting removes the gel coat that prevents germination and kills some seed-borne disease. For peppers, simply scoop the seed out of a fully ripe fruit and dry it. Collect seed from several plants of the same variety, not just one, to keep the variety genetically healthy. Choose the best fruits from the healthiest plants, and avoid seed from diseased plants. Work in dry weather, and handle seed gently — damaged seed germinates poorly.
Drying and storing seed
Drying is the most important step in seed saving: seed that is stored damp will rot or go mouldy. Spread seed in a single layer on a plate, a tray or a sheet of paper in a warm, dry, airy place out of direct sun, and leave it for one to two weeks, turning it occasionally. Seed is dry enough when it snaps rather than bends — a bean that bends is still damp, a bean that snaps is dry. Do not dry seed in an oven or in direct sun, which can kill it. Once dry, clean the seed by winnowing — pouring it from one container to another in a light breeze so the chaff blows away — or by sieving. Store seed in paper envelopes or small jars, labelled with the variety and the date, in a cool, dry, dark place. A sealed jar with a packet of silica gel in a cool cupboard is ideal. Most vegetable seed stays viable for two to five years if stored cool and dry, though some, such as parsnips and onions, lose viability after a year or two. Test old seed before sowing by germinating a few seeds on damp paper.
Keeping varieties pure
If you grow several varieties of a cross-pollinating plant, they can cross and the saved seed will not come true. The simplest way to keep varieties pure is to grow only one variety of each cross-pollinating species for seed, and buy seed for the others. If you want to save seed from several varieties, separate them by distance — the distance needed varies by species, and your local extension service can advise — or hand-pollinate: cover a female flower before it opens, pollinate it by hand with pollen from a male flower of the same variety, and cover it again until the fruit sets. For self-pollinating plants such as tomatoes, beans and peas, crossing is rare and separation of a few metres is usually enough. Keep good records: note which varieties you grew, where, and whether any crossing is likely. If a saved variety starts to look different from the original, it may have crossed — grow it out, select the plants closest to the original, and save seed from those.
Sowing saved seed
Sow saved seed as you would bought seed, but test it first if it is old or you are unsure of its quality. Put ten seeds on damp kitchen paper in a sealed bag, keep it warm, and count how many germinate after a week: if eight or more germinate, the seed is good; if fewer than five germinate, sow thickly or buy fresh seed. Sow saved seed at the usual depth and spacing for the crop, and use our seed starting guide for the right mix and the seed starting calculator for sowing dates. Keep a record of what you sowed, when, and how it did, so you learn which varieties do best in your garden. Share spare seed with neighbours and friends — seed saving is a community activity, and swapping seed preserves varieties that might otherwise be lost. If you save seed from a variety you love, keep saving it every year, because a variety that is not grown is a variety that disappears.
Common mistakes
The most common mistake is saving seed from hybrid F1 varieties, which do not come true — check the packet first. The second is storing seed damp, so it rots or goes mouldy — dry it thoroughly. The third is collecting seed too early, before it is ripe. The fourth is saving seed from only one plant, which narrows the variety's genetics. The fifth is no label, so you cannot tell one saved variety from another. The sixth is growing several varieties of a cross-pollinating crop together and expecting the seed to come true. And the seventh is sowing old seed without testing it, then wondering why nothing grows. Dry seed well, label everything, save from the best plants, and test before you sow.
Frequently asked questions
Can I save seed from any plant?
No. Save seed only from open-pollinated varieties, not from hybrids labelled F1, which do not breed true. Self-pollinating plants such as tomatoes, beans, peas and lettuce are easiest. Cross-pollinating plants such as squash and corn need isolation or hand-pollination to stay true.
How long does saved seed last?
Most vegetable seed stays viable for two to five years if stored cool, dry and dark, though some, such as parsnips and onions, lose viability after a year or two. Test old seed by germinating a few seeds on damp paper before sowing.
How do I dry seeds for storage?
Spread seed in a single layer on a plate or tray in a warm, dry, airy place out of direct sun for one to two weeks, turning it occasionally. Seed is dry enough when it snaps rather than bends. Do not dry seed in an oven or in direct sun.
Why do I need to ferment tomato seeds?
Fermenting removes the gel coat around tomato seed that prevents germination, and it kills some seed-borne disease. Put the seed and pulp in a jar with a little water for two to three days until mould forms, then rinse the seed clean and dry it thoroughly.
How do I keep saved seed from crossing with other varieties?
Grow only one variety of each cross-pollinating species for seed, separate varieties by distance, or hand-pollinate. Self-pollinating plants such as tomatoes, beans and peas rarely cross. If you are unsure about isolation distances, check your local extension service for local advice.