Are Old Seeds Still Good? Shelf Life and the 10-Seed Test
Updated July 31, 2026 · By the makers of Seed Identifier: Sow & Track
The date on a seed packet is a freshness guideline, not an expiry. Seeds are dormant living things: stored well, many outlive their packet date by years; stored in a hot shed, they can die before it. The only date that matters is the one your own test produces.
Typical shelf lives (stored cool and dry)
These assume decent storage. Heat and humidity are the killers: a packet that spent a summer in the greenhouse aged five years in one.
- 1-2 years: onions, leeks, parsnips, spinach; the short-lived crowd
- 3-4 years: carrots, peppers, beans, peas, corn
- 4-5 years: tomatoes, squash, pumpkins, brassicas, basil
- 5+ years: cucumbers, melons, lettuce; the long haulers
- Wildcards: many flowers and natives vary wildly; test rather than assume
The 10-seed paper towel test
Bonus: sprouted test seeds of most vegetables can be planted carefully, so a passed test costs you nothing.
- Count out 10 seeds from the packet in question.
- Space them on a damp (not soaked) paper towel, fold it over, and slide it into a loosely closed plastic bag.
- Keep it somewhere warm (20-25 C, like the top of the fridge) and check every 2 days, re-moistening if needed.
- After the species' normal germination window, count the sprouts: 8 of 10 = strong packet, sow normally; 5-7 = usable, sow thicker; under 5 = replace, or sow very generously if you must.
Storing seeds so this stops being a question
Cool, dark, dry, and airtight: a sealed jar with a silica gel packet in the fridge is the gold standard, and a cool closet beats any shed or windowsill. Label everything with species and year; two minutes of labeling saves the identification job entirely. For saved seeds, dry them thoroughly for a week or two before sealing; trapped moisture is how jars of seeds rot.
When the packet has no name at all
Old saved seeds often lose their labels before their viability. Identify first, then test: knowing the species tells you the expected germination window, without which the paper towel test has no deadline, and it tells you whether the seed needs pre-treatment (some species fail the towel test simply because they wanted a fake winter first).
Name it, then test it, with Seed Identifier
- Photograph the mystery seeds and get the species.
- Check the germination timeframe so your towel test has a real deadline.
- Check pre-treatment needs; a dormant seed is not a dead seed.
- Log the sowing and track the days against the expected window.
AI-powered estimates. Never consume or plant seeds based solely on a photo identification: many seeds are toxic, and some species are regionally restricted or invasive.