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How to Save Seeds From Your Vegetables
Save seed from your best plants, not your leftovers. The genetics you keep are the genetics you get.
Direct answer: Save seed only from open-pollinated varieties, choose the healthiest plants rather than the last ones standing, and process seed either wet (tomatoes, cucumbers) or dry (beans, lettuce, peppers). Dry to under 10% moisture, label with variety and date, and store cool and dark. Hybrid seed will grow, but it will not come true to type.
Which plants save true
| Type | Saves true? | Examples |
|---|---|---|
| Open-pollinated (heirloom) | Yes, with isolation | Brandywine tomato, Cherokee Purple, most beans |
| Hybrid (F1) | No — variable offspring | Most modern sweet corn, many tomatoes and brassicas |
| Self-pollinating | Easy | Tomatoes, beans, peas, lettuce |
| Cross-pollinating | Needs isolation distance | Squash, corn, brassicas, carrots, beets |
Isolation distances vary wildly: beans need 10–20 feet, tomatoes 10–25 feet, squash up to half a mile for absolute purity. In a small garden, focus on self-pollinators first.
Isolation distances at a glance
| Crop | Minimum isolation | Pollination |
|---|---|---|
| Tomato | 10–25 ft | Self |
| Beans, peas | 10–20 ft | Self |
| Lettuce | 10–25 ft | Self |
| Peppers | 50–300 ft | Self, some crossing |
| Cucumber | 500 ft–0.5 mile | Insect |
| Squash | 0.25–0.5 mile | Insect |
| Corn | 0.5 mile or block planting | Wind |
| Brassicas | 0.5–1 mile | Insect |
| Carrots, beets | 0.5–1 mile | Wind/insect |
These are working minimums for home seed saving, not certification standards. If the distances are impossible in your garden — and for squash and brassicas they usually are — grow one variety per species, or hand-pollinate and bag the flowers.
Easiest crops to start with
Start with tomatoes, beans, peas, and lettuce. All four are self-pollinating, all four are easy to process, and all four produce seed in the same season you eat the crop. Add peppers once you are comfortable, then try one insect-pollinated crop with a plan for isolation.
Biennials need two seasons
Carrots, beets, onions, leeks, cabbage, and kale produce seed in their second year. That means overwintering the root or the plant — in a root cellar, a cold frame, or the ground under mulch — and letting it flower the following spring. It is worth doing for one or two crops you care about, but it doubles the space and time a crop occupies.
If you only have one season of attention, stick to annuals: tomatoes, beans, peas, lettuce, peppers, and squash. Save the biennials for a year when you have room to leave a bed occupied through winter.
Wet seeds (fermenting)
Tomatoes and cucumbers have gel sacs that inhibit germination. Fermentation removes them and kills some pathogens.
- Scoop seeds and gel into a jar with a little water.
- Leave 3–5 days at room temperature until a mould layer forms and seeds sink.
- Add water, stir, and pour off the pulp and floating (non-viable) seeds.
- Strain, rinse, and spread on a plate or paper towel to dry for 7–10 days.
- Store in a labelled paper envelope once fully dry.
Dry seeds
Beans, peas, lettuce, peppers, and brassicas are processed dry. Let pods or heads mature on the plant, harvest before they shatter, and dry in a paper bag or on screens in a ventilated room. Thresh by hand or by crushing in a bag, then winnow.
Drying, labelling, storage
- Dry to crisp: a seed should snap, not bend. Aim under 10% moisture.
- Label immediately: variety, year, and any notes. Unlabelled seed is worthless by spring.
- Store: airtight jar with a silica packet, in a cool dark place. A refrigerator is fine if the jar is sealed.
- Viability: 2–3 years for most vegetables, 5+ for beans and tomatoes when stored dry and cool.
Frequently asked questions
Can I save seeds from hybrid plants?
You can, but the offspring will vary and usually disappoint. Save from open-pollinated varieties if you want consistency.
How do I test if old seed is viable?
Put 10 seeds on a damp paper towel in a sealed bag for 7–10 days. If fewer than half sprout, sow thicker or buy fresh seed.
Do I need to isolate tomatoes?
Tomatoes are mostly self-pollinating, so 10–25 feet between varieties is usually enough for home saving.
Why did my saved squash turn out bitter?
Cross-pollination with a wild or different squash variety. Squash needs large isolation distances or hand pollination.
Next: seed-saving mistakes. For the broader garden plan, the quarter-acre guide and the book review cover the seed-saving chapter.
Frequently asked questions
Can I save seeds from hybrid plants?
You can, but the offspring will vary and usually disappoint. Save from open-pollinated varieties for consistency.
How do I test if old seed is viable?
Put 10 seeds on a damp paper towel in a sealed bag for 7–10 days. If fewer than half sprout, sow thicker or buy fresh seed.
Do I need to isolate tomatoes?
Tomatoes are mostly self-pollinating, so 10–25 feet between varieties is usually enough for home saving.
Why did my saved squash turn out bitter?
Cross-pollination with another squash variety. Squash needs large isolation distances or hand pollination.