Seed Saving Guide
Learn how to save seeds from your favorite plants and preserve heirloom varieties for generations. This comprehensive guide covers everything from basic techniques to advanced seed storage.
Getting Started
Seed saving is one of the oldest agricultural practices\u2014and one of the most rewarding. Follow these six steps to begin your seed-saving journey.
Start with Easy Seeds
Begin with self-pollinating annuals like tomatoes, peppers, beans, peas, and lettuce. These plants rarely cross-pollinate and produce seeds in the same season.
Let Fruits Fully Ripen
Seeds need time to mature. Leave fruits on the plant longer than you would for eating—tomatoes should be slightly overripe, peppers turning color, and beans dried on the vine.
Harvest at the Right Time
Collect seeds on a dry day. For wet seeds (tomatoes, cucumbers), harvest when fully ripe. For dry seeds (beans, lettuce), wait until pods are brown and crispy.
Clean and Process
Remove seeds from fruit, clean off pulp, and dry thoroughly. Wet processing works best for tomatoes and cucumbers. Dry processing is for beans, peas, and flowers.
Dry Completely
Spread seeds in a single layer on paper plates or screens. Dry for 1-2 weeks in a warm, well-ventilated area away from direct sunlight. Seeds should snap, not bend.
Store Properly
Place fully dried seeds in paper envelopes or glass jars. Label with variety name and date. Store in a cool, dark, dry place. Many seeds last 3-5 years or longer.
Seed Processing Methods
Different seeds require different cleaning methods. Here's how to process both wet and dry seeds.
Wet Processing
For tomatoes, cucumbers, melons, squash
- 1Scoop seeds and pulp into a glass jar
- 2Add water to cover and stir
- 3Let ferment for 2-4 days, stirring daily
- 4Good seeds sink; scoop off floating debris
- 5Rinse clean seeds in a fine strainer
- 6Spread on a plate to dry for 1-2 weeks
Pro tip: Fermentation is complete when a layer of white mold forms on top. Don't worry\u2014this is beneficial and helps remove germination inhibitors.
Dry Processing
For beans, peas, lettuce, flowers, herbs
- 1Allow seed heads to dry fully on the plant
- 2Cut seed heads and place in paper bags
- 3Thresh by rubbing or shaking to release seeds
- 4Winnow by pouring between containers in a breeze
- 5Remove remaining chaff by hand
- 6Store in labeled envelopes or jars
Pro tip: Winnowing outdoors on a breezy day works best. Pour seeds slowly between two containers\u2014chaff blows away, seeds fall straight down.
Isolation Distances
To keep varieties pure, you need to prevent cross-pollination. Here are recommended isolation distances for common garden crops.
| Plant | Minimum Distance | Notes |
|---|---|---|
| Tomatoes | 10-25 feet | Mostly self-pollinating, but some crossing possible |
| Peppers | 300-500 feet | Insect-pollinated; hot and sweet peppers can cross |
| Squash | ½ mile | Bees travel far; hand-pollinate for purity |
| Corn | 1 mile | Wind-pollinated; very prone to crossing |
| Beans | 10-20 feet | Self-pollinating; minimal isolation needed |
| Lettuce | 10-20 feet | Self-pollinating before flowers open |
| Brassicas | ½ mile | All brassicas cross (broccoli, kale, cabbage) |
| Carrots | ½ mile | Biennial; will cross with wild carrot (Queen Anne's Lace) |
For Small Gardens
Don't have space for half-mile separation? Use these alternatives: grow only one variety of crossing crops per season, use physical barriers like row cover or bags over flowers, hand-pollinate and cover female flowers, or time plantings so varieties don't flower together.
Storage Conditions
Proper storage can extend seed viability from years to decades. The key factors are temperature, humidity, light, and air exposure.
Temperature
32-41°F (0-5°C)
Cool temperatures slow seed aging. Refrigerator storage can double or triple seed life. Avoid freezing unless seeds are completely dry.
Humidity
Below 50% RH
Moisture is seeds' worst enemy. Use silica gel packets in containers. The 100 Rule: temperature (°F) + humidity (%) should equal less than 100.
Light
Complete darkness
Light can trigger germination in some seeds and degrades others. Store in opaque containers or dark locations.
Air
Airtight containers
Oxygen degrades seeds over time. Use glass jars with tight lids or vacuum-sealed bags for long-term storage.
Short-lived (1-2 years)
Onions, leeks, parsnips, chives, parsley
Medium-lived (3-4 years)
Beans, carrots, peas, peppers, lettuce, spinach
Long-lived (5+ years)
Tomatoes, brassicas, cucumbers, melons, squash, beets
Common Mistakes to Avoid
Even experienced gardeners make these errors. Learn from others' mistakes to save time and seeds.
Saving hybrid seeds (F1)
Only save open-pollinated or heirloom varieties. Hybrids won't grow true to type.
Harvesting seeds too early
Wait until fruits are overripe and seeds are fully mature for best germination.
Storing damp seeds
Dry seeds for at least 2 weeks. They should snap, not bend when broken.
Not labeling immediately
Label seeds right away with variety, source, and date harvested.
Saving from few plants
Save from at least 6-10 plants to maintain genetic diversity.
Ignoring isolation distances
Research crossing potential and use physical barriers or timing to prevent it.
Frequently Asked Questions
Got questions? We've got answers to the most common seed-saving queries.
Ready to Start Saving Seeds?
Download the SeedShare app to connect with experienced seed savers, track your varieties, and join a community dedicated to preserving biodiversity.