If you’ve ever bought a packet of fruit, vegetable, herb, or flower seeds at the store, you might have noticed that they are usually stamped with an expiration date. Quite a few people don’t know what that expiration date is for or what its purpose is. Here is the reason for the date.
Actually, the question was asked if it was okay to plant the seeds after the expiration date or if the date meant that the seeds were rotten. This is a very legitimate question since people are commonly used to seeing food stamped with a “use by” date. However, the purpose of that date on a packet of seeds is a little different.
Without going into a great deal of depth, plant seeds are usually good for about one or two years, provided that they are kept dry. However, even if they are kept dry, they do get old. Although there are some exceptions, seeds that are older than a year or two years, depending on the species of plant, have a greater failure rate than seeds that are fresh.
Put in another way, the older the seeds are, the fewer of those seeds will be likely to germinate when they are planted. The drop in germination rate can occur quite rapidly, too. However, that is the purpose for the expiration date; to let consumers know that if the seeds are older than a certain date, the number of those seeds that can be expected to actually grow starts dropping.
It doesn’t mean that the seeds are rotten. I’ve planted vegetable seeds that were over four years old and did have some seeds grow. However, only about 5% to 10% of them did grow. That means that out of every hundred seeds that were planted, only 5 to 10 of them grew. If the packet was new, the expectation would have been a germination rate of above 90%. That is, for a planting of 100 seeds, a person could expect that over 90 of them would grow.
For this reason, stores will often have tremendous sales on old seeds. A packet that normally costs $2 may be sold for half off or more. However, this might not be much of a deal after all. On the other hand, if the packet is being sold for 10 cents, it probably is a really good deal, as long as you realize that you’ll probably need to plant far more seeds to end up with the same number of plants you were expecting to grow.