A packet of vegetable seeds may look dry, brittle, and lifeless, but in many cases, seeds are very much alive. Inside each plant seed is the embryo of a future plant. However, seeds do not remain alive forever. How long seeds remain viable depends on the type of seed and how well it is stored.
Most vegetable seeds remain good for about two to three years, but some, such as onions, deteriorate within a year and others such as lettuce, can successfully sprout after five years. The table below lists average years of viability for well-stored vegetable seeds, compiled from regional sources. There will be some variability because of the variety of seed and whether the seed was fully ripe and kept dry in storage.
You can’t do anything to change the life expectancy of different types of seeds. But if you save your own seed or need to store purchased seed, you can keep it fresh for the maximum amount of time by taking these steps to store it properly.
Realistically, if less than 70% of your test seed germinated, you would be better off starting with fresh seed.
You Will Need:
If 100% germinated, your seed is viable and you’re ready to plant.
If 70–90% germinated, the seed should be fine to use, but you should sow it a little thicker than you normally would.
There’s an easy way to determine how viable your saved seed is and what percentage of it you can expect to germinate.
There is no need to waste the seeds that have germinated; they can be planted. Don’t let them dry out and handle them very carefully so that you don’t break the roots or growing tip. It’s often easiest to just cut the paper towel between seeds and plant the seed, towel and all. If the root has grown through the towel, it is almost impossible to separate them without breaking the root. The paper towel will rot quickly enough and, in the meantime, it will help hold water near the roots.
Many vegetable seeds can be viable for years if they're stored properly. Learn how long each type of seed can survive and how to store and test them.
Seeds in good condition and stored properly will last at least one year and, depending on the plant, may last two to five years. I found a quite a few tables on the internet indicating the average shelf life of vegetable and flower seeds that are properly stored. Those sources are listed below. Here is a shorter version for a variety of vegetable seeds:
- 1 year: onions, parsnips, parsley, salsify, and spinach
- 2 years: corn, peas, beans, chives, okra, dandelion
- 3 years: carrots, leeks, asparagus, turnips, rutabagas
- 4 years: peppers, chard, pumpkins, squash, watermelons, basil, artichokes and cardoons
- 5 years: most brassicas, beets, tomatoes, eggplant, cucumbers, muskmelons, celery, celeriac, lettuce, endive, chicory
If you are uncertain about whether seeds will germinate, you can do an easy germination test. Count out a specific number of seeds, anywhere from ten to one hundred seeds. Moisten a paper towel or a coffee filter and place the seeds on it. Fold or roll up the moistened paper over the seeds, making sure that the seeds don’t touch each other, and put the paper inside a plastic bag in a warm place. Check the seeds after two or three days and then every day thereafter for a week or so. Spray the paper as need to maintain moisture. After the standard germination period has passed (as provided on the seed packet), count to see how many seeds have germinated and calculate the percentage of germination by dividing the number of seeds germinated by the number of seeds tested. Compare the germination percentage it to the germination rate (if there is one) on the seed packet label. If the seed germination rate is high, then the seeds are fine to plant. If the germination rate is low, you may want to purchase new seeds.
Each winter, I start thinking about what seeds I may want to plant in my garden for spring and summer. Before I get too far in my planning, I first rifle through the half-empty packets of seeds left over from the prior year (and in some cases, several years) and wonder if any of them are still viable. I usually shrug, toss the seeds in the ground, and wait to see what happens. If the seeds don’t germinate, then I buy some new ones. Obviously, this haphazard approach to planting is far from ideal because it can put me several weeks behind my intended planting schedule by the time I notice that the seeds haven’t germinated.
But this year, I decided to do a little research about how long seeds last. I was a little surprised to learn that seed viability varies considerably with the type of plant. Seed viability also will vary depending on whether the seeds are have been pretreated or pelletized. I was less surprised to learn that viability varies even under optimal storage conditions.
Sources for seed viability tables:
Seeds should be stored in cool, dry, dark conditions. Place the seeds in an airtight, watertight container such as a jar with a rubber seal (like a baby food jar or canning jar) or a zip lock bag inside a jar. To keep the seeds cool (ideally, below 50 degrees), some people store them in a jar in their refrigerator or freezer.
Vegetable and flower seeds
Seasonal observations of the Master Gardeners