How to Save Seeds

Quick steps

1. Pick open-pollinated or heirloom varieties. F1 hybrids will not breed true. Check the seed packet or look up the variety at Seed Savers Exchange (US) or Seeds of Diversity Canada.
2. Wait for full ripeness. Wet seeds (tomato, cucumber, melon) need overripe fruit; dry seeds (beans, peas, lettuce) need brown and brittle pods or seed heads.
3. Choose the method. Wet-fermentation for tomato / cucumber / melon / tomatillo. Dry method for beans / peas / peppers / lettuce / brassicas / herbs.
4. Dry to 8 percent moisture. Beans snap, tomato seeds break papery, lettuce crushes to dust. Add silica gel desiccant for the first month.
5. Store cool, dark, dry, sealed. Glass jars with screw lids. Refrigerator at 32 to 41 F (0 to 5 C) is ideal; cool closet works for 1 to 3 years.
6. Label and log. Crop, variety, year saved, source. Use the Seed Saving Log printable.
7. Retest annually. 10-seed paper-towel test before relying on stash for spring sowings.

Easy vs hard seed-savers

Self-pollinated annual crops are forgiving for first-time seed savers. Cross-pollinated and biennial crops require isolation distance and overwintering, which most home gardeners skip on the first attempt.

"Self-pollinated" means a single isolated plant produces viable true-to-type seed. "Cross-pollinated" means at least 1 to 5 plants of the same variety, separated by isolation distance from any other variety of the same species. "Biennial" means the plant flowers and sets seed in its second year and has to overwinter, so seed saving requires either mild winters or root cellaring.

Wet-fermentation method

For tomato, cucumber, melon, and tomatillo. Fermentation breaks down the seed’s gel coating (which inhibits germination) and reduces seed-borne disease.

1. Pick fully ripe or slightly overripe fruit. Tomato should be soft to the touch; cucumber yellow and starting to wrinkle; melon past dessert ripeness.
2. Scrape seeds plus gel into a glass jar or cup. Wide-mouth pint jar works well. Add a splash of water (roughly equal volume to seeds plus gel).
3. Cover loosely and ferment 2 to 4 days at 65 to 75 F (18 to 24 C). Stir daily. The mix smells yeasty after 24 hours; that is normal.
4. Watch for the layer indicator. Viable seeds sink to the bottom; non-viable seeds and gel form a moldy raft on top. When the raft is fully formed (typically day 3 or 4), proceed.
5. Rinse vigorously. Pour off the moldy layer and floating debris. Add water, swirl, pour off floaters again. Repeat until rinse water runs clean.
6. Drain and dry. Pour seeds onto a labeled coffee filter, paper plate, or window screen. Avoid paper towels (seeds stick). Spread in a single layer in a warm, dry, ventilated spot out of direct sun.
7. Dry 1 to 2 weeks. Stir or break up clumps daily. Done when seeds break crisply between fingernails (tomato), snap (bean), or shatter (pepper).

Dry-extraction method

For beans, peas, lettuce, brassicas, peppers, herbs, and most flowers. Let nature do the drying; you collect at peak.

1. Mark the saved plants early. Tie a colored ribbon or flag at flowering time so you do not harvest the seed-stock plants by accident.
2. Wait for full plant maturity. Beans and peas: pods rattle when shaken. Lettuce: seed heads fluffy and starting to drop. Brassicas: pods brown and dry. Peppers: fruit fully ripe (red, yellow, or orange).
3. For shattering crops, bag the seed heads. Lettuce and brassicas drop seeds quickly. Slip a paper bag over the seed head, tie at the stem, and let the bag catch falling seeds.
4. Thresh: separate seed from chaff. Rub pods or seed heads between hands over a bowl. Beans and peas often need pods cracked open by hand. Tougher pods can be flailed gently inside a pillowcase.
5. Winnow: blow off chaff. Pour seeds slowly between two bowls in a light breeze (or in front of a fan). Lighter chaff drifts away; heavier seeds drop straight down.
6. Final drying. 1 to 2 weeks at room temperature, low humidity, out of direct sun. The seeds need to be drier than they feel; add silica gel desiccant for the last week to confirm.
7. Pepper note. Pull seeds from a fully ripe pepper, lay flat on a labeled plate, dry 1 to 2 weeks. Wear gloves for hot peppers; capsaicin transfers to skin and eyes.

Once dried, log every batch in the Seed Saving Log printable. Crop, variety, harvest date, drying method, source.

Dry to the right moisture target

The most common seed-storage failure is insufficient drying. Aim for 8 percent moisture for most vegetable seeds; 5 to 6 percent for long-term storage.

• Practical test by crop. Bean / pea: snaps cleanly when bent, no give. Tomato: brittle, breaks papery between fingernails. Lettuce: crushes to dust between fingernails. Pepper: breaks crisply, not leathery. Squash family: feels almost ceramic.
• Silica gel desiccant. 40 to 50 grams (1.4 to 1.8 oz) per quart-sized jar pulls remaining moisture down to safe levels in 30 days. Use indicator silica (color-changing) to know when it is saturated; recharge by baking at 250 F (120 C) for 2 hours.
• Avoid heated drying. Above 95 F (35 C) cooks the seed embryo. Air drying at room temperature is safer than oven or food dehydrator drying.
• Humidity matters more than time. Drying takes 1 to 2 weeks at 30 percent humidity, 3 to 4 weeks at 60 percent humidity. In humid climates, indoor drying with a dehumidifier is faster than outdoor drying.
• Smell test. Dry seeds smell neutral or earthy. Wet or insufficiently dried seeds smell musty or sweet. Either smell means more drying is needed.

Storage: cool, dark, dry, sealed

• Glass jars beat plastic and paper. Mason jars or peanut-butter jars with intact rubber seals. Plastic absorbs odors and can leach. Paper envelopes are fine inside a sealed jar but not as the only barrier.
• One species per jar. Multiple varieties of the same crop can share a jar; mixing crops increases cross-contamination risk.
• Bring frozen seeds to room temp before opening. Cold seeds in a warm humid kitchen condense moisture immediately. Let the closed jar warm up for 24 hours before opening.
• Add a desiccant packet for the first month. Silica gel locks in low moisture during the temperature transition. Remove or refresh after 30 days.
• Store away from light. UV degrades seed viability over months. A cardboard box, opaque container, or cabinet works.

Labeling: 4 fields minimum

Unlabeled seeds become unidentified seeds within 6 months. Four fields cover everything you need.

• Crop name and variety. “Tomato, Brandywine” not just “Tomato”. Variety matters for cross-checking against the original seed source.
• Year saved. Any saved seed should carry the harvest year. Storage life depends on it.
• Source. Where the parent seeds came from: a seed company name, a friend’s garden, a Seed Savers Exchange or Seeds of Diversity Canada listing, or "self" for second-generation saved seed.
• Notes. Optional but useful. Disease resistance observed, days to maturity, taste notes, any cross-pollination risk if isolation was imperfect.
• Permanent marker on the jar lid plus a paper label inside. Markers fade; paper labels survive the lifetime of the jar. Do both.

Track every saved batch alongside next-spring sowing labels with the Seed Inventory Sheet and the Seed Starting Tray Label Template.

Germination retest schedule

Seed viability drops gradually with storage. A 5-minute test before sowing prevents an empty bed in spring.

• Test any seed older than 1 year. Even refrigerated seeds lose germination over time. The 10-seed paper-towel test costs nothing and takes 5 to 14 days depending on the crop.
• Method. Place 10 seeds on a moist paper towel, fold, slip into a zip-top bag, keep at 70 F (21 C). Count sprouts at the typical days-to-germination for that crop.
• Reading results. 8+ of 10 (80 percent or higher): excellent, sow at normal density. 6 to 7 of 10 (60 to 80 percent): workable, sow 30 percent extra. Below 6 (under 60 percent): time to source fresh seed; existing stash is end-of-life.
• Crop-specific shelf life. Onion, parsnip, sweet corn: 1 to 2 years (short). Bean, pea, carrot, pepper, lettuce: 2 to 4 years. Tomato, melon, squash, cucumber: 4 to 6 years. Brassicas (kale, broccoli, cabbage): 4 to 5 years.
• Track results. Use the Seed Germination Test Log printable. Year-over-year comparison reveals storage problems early.

Common mistakes

• Saving from F1 hybrids. The seedlings will not look or perform like the parent. Stick to open-pollinated and heirloom varieties.
• Saving before full ripeness. Tomato seeds from a green tomato often will not germinate; pepper seeds from an unripe pepper rarely sprout. Wait for full color or full plant maturity.
• Insufficient drying. Mold grows on stored seeds within weeks if moisture is above 10 percent. Dry until snap-crisp, plus a desiccant packet to be sure.
• Skipping the wet fermentation on tomatoes and cucumbers. The gel coating inhibits germination; fermentation removes it and reduces seed-borne disease.
• Storing in the garage or shed. Heat above 90 F (32 C) and humidity above 60 percent kill seed life within months. Use indoor cool storage minimum.
• Mixing varieties in one jar. “Tomato seeds” without variety becomes useless when sowing. One variety per jar; one jar per crop minimum.
• Not labeling the year. A 6-year-old onion seed stash is lower viability than fresh; a 6-year-old tomato seed stash is fine. Year is the most important label field.
• Skipping the germination retest. 5 minutes saves an empty spring bed. Test any seed older than 1 year before relying on it.

FAQ

Bottom line

Save from open-pollinated and heirloom varieties only. Wet-ferment tomato, cucumber, melon, and tomatillo seeds. Dry-extract beans, peas, lettuce, peppers, brassicas, and herbs. Dry to 8 percent moisture (snap-crisp). Store cool, dark, dry, and sealed in glass jars at room temperature for 1 to 3 years or refrigerator at 32 to 41 F (0 to 5 C) for 3 to 8 years. Label crop, variety, year, and source. Retest with a 10-seed paper-towel test before relying on year-old or older seeds. Track every batch in the Seed Saving Log, inventory the stash with the Seed Inventory Sheet, retest with the Seed Germination Test Log, and label spring sowings with the Seed Starting Tray Label Template. Both Seed Savers Exchange (US) and Seeds of Diversity Canada offer free crop-specific guides if you want a deeper dive.