How Long Do Seeds Last? Test Old Packets Before Replacing Them

Vegetable seed kept cool and dry can reasonably be stored for 1 to 5 years, depending on the crop (Utah State University Extension). Age alone cannot say how a given packet will do; a 25-seed paper towel test gives a better read and sets how thickly to sow.

Sources: Utah State University Extension, Cornell Small Farms Program, eCFR. See the sources we used. How we source our guides

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Vegetable seed kept cool and dry can reasonably be stored for 1 to 5 years, depending on the crop: Utah State University Extension's table runs from 1 year for parsley and parsnip to 5 for cucumber, radish, spinach and others. Those years are storage-dependent guidance, not expiry dates, so age alone cannot tell you how a given packet will do. A sample gives a better read: sprout 25 seeds in a damp paper towel and work out the rate below before you give the packet a bed.

How long do seeds last? Years by crop

Utah State University Extension's figures for seed stored cool and dry, for all 31 crops in its table. A linked name goes to our guide for that crop or its family.

How long vegetable seed lasts in cool, dry storage
Crop Years in cool, dry storage
Parsley 1
Parsnip 1
Leek 2
Okra 2
Onion 2
Sweet corn 2
Asparagus 3
Beans 3
Cabbage 3
Carrot 3
Pea 3
Beets 4
Broccoli 4
Brussels sprouts 4
Cauliflower 4
Kale 4
Pepper 4
Pumpkin 4
Swiss chard 4
Tomato 4
Celery 5
Cucumber 5
Eggplant 5
Kohlrabi 5
Lettuce 5
Muskmelon 5
Radish 5
Spinach 5
Squash 5
Turnip 5
Watermelon 5

Source: the "Relative Longevity (Years)" column of USU's seed table. Read each figure as a rough span under good storage, not a date the seed dies. We leave out the table's minimum germination column, drawn from the Utah Department of Agriculture and Food's seed standards: a state standard is not a pass mark for the seeds on your towel.

Before you test: check the packet

Age is one clue among several. Check four things.

  1. What it is and when you got it. USU suggests keeping seed in its original packet, the simple way to remember the kind and when you bought it.
  2. Where it was kept. Warmth and high humidity speed the loss of viability, says USU, whose vegetable guide warns against storing seed above 70 F or above 60 percent humidity. A packet left in a hot shed has aged faster than its date.
  3. Primed or pelleted. USU says to use primed seed in the season you buy it, since it does not store well, and to test pelleted seed kept more than 2 years.
  4. Treated. Federal rules require treated seed to say so on its label and name the substance (7 CFR 201.31a). Handle it as the label directs, away from food.

Test any packet older than its row in the table, of a crop the table does not list, kept warm or damp, or pelleted and over 2 years old. The flow below sums it up.

Sow it, or test a sample first? Sow it, or test a sample first? Question 1: Is the seed primed? Yes: go to question 2. No: go to question 3. Question 2: Did you buy it this season? Yes: Sow it this season. No: Test a sample first. Question 3: Is it past its years in the table or not listed there, kept warm or damp, or pelleted and over 2 years old? Yes: Test a sample first. No: Sow it. QUICK DECISION Sow it, or test a sample first? Q1 Is the seed primed? Q2 Did you buy it this season? Yes A Sow it this season Primed seed does not store well Yes B Test a sample first 25 to 50 seeds in a damp paper towel No Q3 Is it past its years in the table or not listed there, kept warm or damp, or pelleted and over 2 years old? No B Test a sample first 25 to 50 seeds in a damp paper towel Yes C Sow it Follow the crop guide for timing and depth No

How to do a seed germination test with a paper towel

This is Utah State University Extension's home method. Use seed sold for planting, keep the towels and seeds away from food, wash your hands afterward, and never eat test seeds or their sprouts. Sprouts for eating are a different product, covered in our sprouts guide.

  1. Wet two or three paper towels stacked on top of each other.
  2. Lay 25 to 50 seeds in lines across the uppermost towel, then fold or roll the stack closed.
  3. Slip the roll into a plastic bag and leave the bag open.
  4. Keep it in a warm spot such as a kitchen counter, clear of food; USU says 70 to 80 F suits most seeds.
  5. Every 2 or 3 days, unroll it, count and note the seeds that have put out a root, and take them out.
  6. Keep checking until no more sprout. That depends on the crop: in USU's examples radishes sprout in 2 or 3 days and peppers may need 10 to 14 days, so there is no single deadline.
  7. Add up your counts and work out the rate below.

Work out the germination rate

Formula: rate (%) = 100 x seeds that sprouted / seeds tested.

Example: 18 of 25 seeds sprouted: 18/25 = 72%.

The rate describes the seeds you tested, not the whole packet: another 25 can give a different count, and the smaller the sample, the more one seed moves the figure. There is no pass mark; use the number to set how thickly you sow. For a rate lower than normal, USU advises sowing two or three times the usual seed and not saving that seed for later years.

Why the garden can come up thinner than the towel

In our reading, a towel test counts germination in easy conditions: warm, evenly damp, no crust to push through, nothing to eat the seedlings. The garden asks for establishment, seeds that come up and keep growing in your soil, so a bed can come up thinner than the towel suggested. USU also separates germination from vigor, the strength of the seedlings that do sprout, and says heat and humidity in storage reduce both. Sow at the soil temperature and depth the crop's guide gives.

How to store seeds so they last longer

  • Cool and dry. USU's vegetable guide puts the ideal at 35 to 40 F with relative humidity under 40 percent.
  • Sealed. USU suggests mason jars with good lids or buckets with a rubber seal. A refrigerator runs about 40 F but is humid, so seal what goes in.
  • Dark and steady. In a Cornell Small Farms article, seed grower Petra Page-Mann favors a dry, dark kitchen cupboard over a spot that is only sometimes cold, and a basement only if it has low humidity. Her rule of thumb: temperature in F plus relative humidity in percent should total less than 100.
  • Frozen, sealed and dry. In an airtight container, frozen seed can last up to 10 years, says USU. Page-Mann says to freeze only completely dry seed, and that for seed you will sow within a few years, freezing makes little difference.
  • Short-lived seed first. Use onion, leek and parsnip seed soon: USU gives them 1 to 2 years, and Page-Mann goes further: she would not keep onion-family or parsnip seed past one season.
  • Labeled. Mark each packet or jar with the crop, the variety and the year (USU).

What you'll need for storing seed

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    USU suggests mason jars with good lids or buckets with a rubber seal.

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Sources we used

Read and saved on October 29, 2026. USU is Utah State University Extension.

Once you know what is worth sowing, the crop guide covers when, how deep and how far apart.

Frequently asked questions

Do seeds expire after the date on the packet?

No, a packet date does not mark the day the seed dies. Utah State University Extension says viability declines over time, faster in warm or humid storage, and that seed kept cool and dry can reasonably be stored for 1 to 5 years, depending on the crop. Test 25 seeds before you write a packet off.

Why do fewer seeds come up in the garden than in a paper towel test?

In our reading, a damp paper towel is an easier place to sprout than a garden bed. It stays warm and evenly moist, and Utah State University Extension says 70 to 80 F suits most seeds, while a bed can be colder, crusted or dry. USU also says heat and humidity in storage reduce seedling vigor, not just germination.

How many seeds should I use for a germination test?

Use 25 to 50 seeds, the sample Utah State University Extension gives for its paper towel test. A larger sample gives a steadier figure: one seed is 4 percent of a 25-seed sample but only 2 percent of a 50-seed one. Count every seed you lay out and note each check.

How long do seeds last in the freezer?

Up to 10 years, by Utah State University Extension's figure, if the seed is sealed in an airtight container so freezer moisture cannot reach it. A Cornell Small Farms article adds two points: freeze only seed that is completely dry, and for seed you will sow within a few years, freezing makes little difference.

Which vegetable seeds go bad the fastest?

Parsley and parsnip, at 1 year in Utah State University Extension's table, then leek, okra, onion and sweet corn at 2 years. A Cornell Small Farms article goes further: it advises against keeping onion-family or parsnip seed more than one season. Test any of these before you count on an older packet.