In the USA, seeds are tested for germination in Fall and packaged for the next year. So those labeled 2014 should should have the germination rates listed if planted early in 2014 . Onions may fall below that if you wait for fall planting as they are relatively short life seeds. Still good. Example. I just recieved 1000 seeds of Miss Megan , Tested at 75% germination in August and packaged for 2014. I will plant them the first of September and expect a germination rate of less than 75%.

You should look at the test date as Farmerdill noted but if you want to keep onion seeds for another season all you need to do is keep them stored in your freezer. I have had excellent germination results with onion seeds held for 7 years that way. The tricky part is to avoid condensation when using a portion of those seeds. I pour an amount out of the packs I want while never removing the seed packs from the freezer compartment. Since I order larger quantities of these seeds I test germination (by planting) soon after receiving the seeds and I wouldn't hesitate to call the company if germination results were poor.