Seeds & Seed Saving
A seed library is the ultimate food security backstop. If every plant in your garden fails — to drought, frost, pests, or blight — a good seed supply means you replant next season. If seed markets are disrupted, you have independence. The total cost to maintain a household seed supply covering 20–30 crop varieties is inexpensive — affordable in seeds and minimal per year in storage materials.
This page covers the three critical competencies: choosing the right seeds, storing them to maximize viability, and saving seeds from your own crops to become fully self-sufficient.
Understanding Seed Types
Open-Pollinated (OP) Varieties
Open-pollinated varieties reproduce true from seed — plants grown from saved OP seed will be genetically similar to the parent plant. They are pollinated by insects, wind, or self-pollination in natural conditions. All heirloom varieties are open-pollinated. This is the only type worth saving.
Hybrid (F1) Varieties
Hybrid seeds are produced by crossing two distinct parent lines. The F1 (first filial) generation exhibits "hybrid vigor" — often higher yields or disease resistance than either parent. However, seeds saved from F1 hybrids produce unreliable F2 offspring — often reverting to one or both parent types, or producing intermediate results. Do not save seeds from hybrids for replanting if you want predictable crops.
GMO Varieties
Genetically modified organisms have DNA from other organisms inserted via laboratory processes. Patented and licensed — seed saving from GMO crops is illegal under most licensing agreements and practically impossible for households anyway. Not available in home garden seed catalogs; relevant only in commodity agriculture.
Recommendation: Build your seed supply entirely from open-pollinated heirloom varieties. They cost the same as hybrids in catalogs (inexpensive per packet), perform excellently, and give you seed independence.
Seed Viability: How Long Seeds Last
Seeds lose viability over time. The rate depends heavily on storage conditions, but here are standard viability ranges under good (cool, dry) storage:
| Crop | Typical Viability (Good Storage) | Notes |
|---|---|---|
| Onion | 1 year | Replace annually; viability drops sharply |
| Parsley | 1–2 years | Slow germinators even when fresh |
| Sweet corn | 2–3 years | Moisture-sensitive; seal well |
| Leek | 2–3 years | Similar to onion |
| Pepper | 2–4 years | Store at low humidity |
| Bean (snap and dry) | 3–4 years | Reliable storage crop |
| Carrot | 3–4 years | Test before planting |
| Pea | 3–4 years | — |
| Cabbage / Brassicas | 3–5 years | Most brassicas store well |
| Cucumber | 5–7 years | Excellent viability |
| Squash / Pumpkin | 4–6 years | Dry thoroughly before storage |
| Tomato | 4–6 years | One of the best-storing vegetables |
| Watermelon | 4–6 years | — |
| Lettuce | 3–6 years | Varies by variety; test after 3 years |
| Spinach | 3–5 years | — |
These ranges assume optimal storage conditions (32–50°F / 0–10°C, under 50% relative humidity, darkness). Poor storage — a hot humid garage — can cut viability in half within one season.
Seed Storage: The Conditions That Matter
The enemies of seed viability are heat, moisture, and light. Each doubles the speed of deterioration.
The seed storage rule of thumb: Temperature + relative humidity should add up to less than 100 for storage lasting more than one year. Example: 50°F + 45% RH = 95 — acceptable for long-term storage.
Optimal Storage Conditions
- Temperature: 32–50°F (0–10°C) — a dedicated section of a regular refrigerator works well
- Relative humidity: Below 50%; below 35% for multi-year storage
- Light: Complete darkness
- Container: Sealed glass jars or airtight plastic containers with a silica gel desiccant packet (inexpensive for a pack of 25) inside each container
Storage Container Options
| Container | Cost | Notes |
|---|---|---|
| Mason jar with rubber-sealed lid | inexpensive | Excellent; store in refrigerator |
| Mylar bags with oxygen absorbers | inexpensive each | Best for 5–10 year storage; use with desiccant |
| Seed envelopes in an airtight tin | inexpensive for tin | Convenient for many varieties; use with desiccant |
| Vacuum-sealed bags | inexpensive each | Works well with desiccant; check seal annually |
Do not use regular zip-close plastic bags for storage beyond one season — they are not moisture barriers and allow vapor exchange.
Labeling Requirements
Every stored seed packet must have: - Variety name - Year harvested or purchased - Source (if purchased: seed company; if saved: your plant) - Germination rate if tested (update each time you test)
A mislabeled or unlabeled seed supply creates planning failures at the worst possible time — the planting window.
Germination Testing: The 10-Seed Protocol
Test seeds before a major planting season, especially for any variety that is 3+ years old or was stored in suboptimal conditions. This procedure takes 7–14 days depending on crop.
Materials
- 2 sheets of paper towel per test
- 1 zip-close plastic bag per variety
- Water (room temperature)
- Warm location (65–75°F / 18–24°C) — top of refrigerator, near a water heater, or in a consistently warm room
Procedure (Step by Step)
- Count out exactly 10 seeds from the lot you want to test.
- Dampen one paper towel sheet — moisten thoroughly, then wring out so it is damp but not dripping.
- Lay 10 seeds in a row near one end of the damp paper towel, spaced 1 in (2.5 cm) apart.
- Fold the towel over the seeds, then fold it in half again to create a packet.
- Seal the packet inside a labeled zip-close bag. Label with variety name and test start date.
- Place in a consistently warm location — 65–75°F (18–24°C) is optimal for most crops. Some crops (peppers, tomatoes) prefer 75–80°F (24–27°C).
- Check daily starting at the expected germination day for that crop.
When to Check and What Counts
A seed "germinates" when the radicle (root tip) has emerged at least 1/8 in (3 mm). Do not count seeds that have swelled but not sprouted.
| Crop | First Check | Full Count |
|---|---|---|
| Radish, lettuce, spinach | Day 3–4 | Day 7 |
| Bean, cucumber, squash | Day 3–5 | Day 7–10 |
| Tomato, pepper | Day 5–7 | Day 10–14 |
| Parsley, carrot | Day 10–14 | Day 21 |
| Onion, leek | Day 7–10 | Day 14 |
Interpreting Results
| Seeds Germinated (of 10) | Germination Rate | Action |
|---|---|---|
| 9–10 | 90–100% | Excellent; plant at normal rate |
| 7–8 | 70–80% | Acceptable; plant 20–30% more densely |
| 5–6 | 50–60% | Marginal; plant at double density; replace soon |
| Below 5 | Below 50% | Replace before critical planting window |
Field Note
Always test seeds from your single most critical staple crop — the one whose failure would cause the most hardship — at least 6 weeks before the planting window. That gives you time to source replacements. Onions have the shortest viability (1 year) and one of the longest growing seasons — they need to go in the ground before most other crops. Test onion seeds in January for a late February/March start in Zone 6.
Seed Saving: Techniques by Pollination Type
To save seeds successfully, you must understand how your target crop is pollinated. This determines whether cross-pollination is a risk and what isolation measures are required.
Self-Pollinators (Easiest)
These flowers contain both male and female parts and pollinate themselves before or as the flower opens. Cross-pollination risk is very low. Best crops to start with for seed saving.
Examples: Tomatoes, peppers, beans, peas, lettuce, eggplant
Technique for tomatoes: 1. Choose the largest, most vigorous fruit from your best plant. Mark the plant with a stake when it is flowering so you can track it. 2. Allow the fruit to fully ripen beyond eating stage — for tomatoes, let the fruit sit on the vine until it begins to soften further than you would eat it; another 1–2 weeks past prime. 3. Slice the fruit and scoop seeds and gel into a glass jar with an equal volume of water. 4. Ferment for 1–3 days at room temperature, stirring daily. Fermentation destroys germination-inhibiting compounds in the gel and kills some seed-borne pathogens. A gray or white mold on the surface indicates fermentation is complete. 5. Add a large amount of water and stir — viable seeds sink, debris and non-viable seeds float. Pour off the floating material; repeat 2–3 times. 6. Spread viable seeds on a non-stick surface (ceramic plate, glass, or wax paper) and dry in a single layer at room temperature for 1–2 weeks, stirring daily. 7. Seeds are dry enough to store when they snap cleanly and do not bend.
Technique for beans and peas: 1. Allow pods to dry completely on the vine — pods should be papery and the seeds rattling inside. 2. Shell pods and spread seeds for 1–2 weeks of additional drying. 3. Test: bite a seed — it should be rock-hard. Any flexibility indicates inadequate drying.
Cross-Pollinators (Moderate Complexity)
These crops are pollinated by insects or wind carrying pollen between plants. Saving pure seed requires either isolation distance or mechanical exclusion.
Examples: Cucumbers, squash, melons, corn, brassicas (cabbage, broccoli, kale)
Isolation distances for home gardens:
| Crop | Minimum Isolation Distance |
|---|---|
| Cucumbers | 500 ft (152 m) from other cucumber varieties |
| Summer squash | 1/4 mile (400 m) — all Cucurbita pepo cross freely |
| Corn | 1/4 to 1/2 mile (400–800 m) — wind-pollinated; highly promiscuous |
| Brassicas | 300–1,000 ft (90–305 m) depending on species |
| Melons | 500 ft (152 m) from other melons of same species |
Bagging technique (for small-scale saving without isolation distance): 1. Select one or two plants designated for seed saving. 2. The night before a female flower is expected to open, loosely bag it with a small cloth bag, paper bag, or floating row cover secured with a twist tie. 3. When the female flower is receptive (stigma moist and sticky), collect pollen from a male flower on the same or another plant of the same variety (using a cotton swab or by rubbing directly). 4. Hand-pollinate the bagged female flower; re-bag until the flower closes. 5. Mark the hand-pollinated fruit with a tag. Allow it to mature fully for seed harvest.
Biennials (Advanced)
Some crops only produce seed in their second year of growth: carrots, beets, cabbage, onions, parsley, and leeks flower and set seed after overwintering.
Technique: In fall, select the best roots or plants. In cold climates, dig roots and store in a root cellar through winter (see root cellar storage); replant in spring. In mild climates, leave in the ground and mulch. Allow plants to bolt and fully mature seed stalks. Harvest when seed heads are dry.
Building a Seed Bank
A functional household seed bank covers: - 8–12 vegetable crops (prioritize what you eat) - Multiple varieties per crop for genetic diversity (2–3 varieties of tomato, 2 of squash) - At least 2–3 seasons of viable seed in reserve for each critical crop
Recommended starter collection: - Tomatoes: 2 open-pollinated varieties (e.g., Mortgage Lifter, Roma) - Peppers: 1 sweet, 1 hot (e.g., California Wonder, Cayenne) - Beans: 1 bush dry bean (e.g., Jacob's Cattle, Calypso) - Squash: 1 winter squash (e.g., Butternut, Delicata) - Lettuce: 1 loose-leaf variety (e.g., Black-Seeded Simpson) - Kale: 1 cold-hardy variety (e.g., Red Russian, Lacinato) - Radishes: 1 quick variety (e.g., Cherry Belle) - Basil: 1 sweet basil
These 8–10 packets are inexpensive each and represent an affordable foundation for a functional seed bank. Rotate and test annually.
Cross-References
- Gardening — crop planning and planting schedules that use your seed supply
- Permaculture — seed saving in the context of a perennial system with open-pollinated annuals
- Root Cellar — cool storage conditions that extend seed viability in the same space as food storage
- Long-Term Food Storage — dry storage strategy where seeds fit naturally
Practical Checklist
- Audit current seed supply: note variety, year, and source for each packet
- Replace any onion, leek, or parsley seed older than 1–2 years
- Set up airtight storage with desiccant packets in a cool, dark location
- Run 10-seed germination tests on any seed older than 3 years
- Convert at least 3 crops to open-pollinated varieties for seed saving
- Save seeds from one self-pollinating crop (tomato or bean) this season
- Label all stored seed with variety, year, and germination rate
- Review and restock seed supply each winter before ordering for the coming season