The short answer is: Probably. Seed life and viability varies significantly among garden species. Certain seed sources may have you believe that seeds are suitable for sowing for just one season, but this is rarely the case. Parsnip and Chervil seeds should absolutely be purchased every year. Salsify is another that I would recommend buying annually. Allium species, particularly A. cepa, are notoriously difficult to germinate in the second year, although they will often germinate just fine if sown outdoors in late winter. Garden species derived from persistent weeds, like Chicory and Purslane, have very long lives indeed, remaining viable for a decade or more. Solanaceae family members, including Tomatoes and Peppers, are likewise very long lived.
Storage conditions can also affect seed life. Consistently cool dry conditions are the best for maintaining viability. Moisture and extreme fluctuations in temperature will significantly damage seeds. Some seeds can survive being frozen (beans fare very well), while others can be killed by such a harsh environment. An airtight container kept away from heat and light in a typical air-conditioned home is generally suitable for storing garden seeds.
Another aspect of seed life that gardeners frequently neglect to consider is that not every seed is viable to begin with. This is just a fact of nature. The standards published and enforced by the USDA are very low (see chart at right), and the majority of the seeds we sell at Farmacie Isolde far exceed those standards, but few if any seed lots test at 100%. Germination rates decrease only slightly during the years in which seeds are viable. Some species, like Beta vulgaris, occasionally see increased germination rates in the second or third year followed by slowly diminishing germination in subsequent years (which only makes them easier to thin, honestly).
Below you will find information as published by Vilmorin in ‘The Vegetable Garden’ in 1885 (and originally in French) regarding common garden seeds and the “Average and Extreme Periods of the Duration of their Germinating Power.”
In summation, don't throw old seeds away. Most common garden seeds can be tested indoors at any time during the winter using nothing more than a bit of moist soil or sand in an old plastic baggie. Kept warm and moist in bright light viable seeds will begin to germinate in a matter of days. If you find buckets of free seeds from last year at the hardware store don't hesitate to take a few. Gardening is always a bit of a gamble, but sowing last years’ seeds should be the least of your worries.
