How long do unplanted organic seed packets last if unopened?
Ventura County California
Thanks for writing to us. Assuming you are referring to vegetable seeds, you can use the following chart as a guideline for the length of viability: http://www.ipm.iastate.edu/ipm/hortnews/1999/4-2-1999/veggielife.html
This information is based on averages and optimum storage conditions including a cool, dark and dry place. It is generally best not to store them in a refrigerator because of the humidity, especially when they are removed from the fridge. For the same reason, it is best to store them in paper instead of plastic bags. If your climate is very hot (making refrigeration necessary) place the seed packets in a sealed container such as a glass jar; then let them come to room temperature before opening the jar.
Keep in mind that seeds generally lose viability gradually. The germination rate may be reduced, but you can still use the seeds by planting more than normal. A easy way to check germination rate is to place 10 seeds in a folded paper towel that has been wrung out of water. Place the paper towel in a ziplock bag, but do not seal it. Just fold the top over, loosely. Place the bag in awarm dark place for about 10 days, then count how many of the seeds germinated. If only 5 have sprouted, your germination rate is 50% so you should sow twice as many.