Do Seeds Expire?

I received a great email today from a gardener I helped mentor last year. We met for three hours, mapped out her year garden plan and she took off running! Her garden prospered last year, and I'm happy to hear she is ready to dig in for 2010. Here is her question, along with my answer: My question for you is about the dates on seed packets.  Are seeds only good for one year?  Should I not be using any of my leftover seeds from last year?  My Fedco seeds from last year are specifically stamped “09”.  Many of my Seeds of Change seeds from last year have 2010, or even 2011!  I’d love to use up these seeds, but wanted to see if “09” seeds were done for....I even have seeds that have a “sell by” date of 12/09.  Would they be OK to plant?

PLANT THOSE SEEDS! Certain families of plants have longer seed lifes than others, but definitely plant them and see if they germinate. If nothing sprouts in 2 weeks, they are 'bad' seeds. But the odds of that happening are 50-50, so definitely give them a go. I planted seeds from 2007 last year with success.

Also good to note......any left over seeds should be kept in glass jars with lids, sealed and held in a cool dark cupboard. This will extend their life from year to year!