Q: I have some cosmos and zinnia seeds from last year that I never planted. Can I plant them this year?
A: A garden friend recently presented me with seed packets he’d found in his mother’s cabinets. One pack was “Mixed Herbs” with a label saying it was packed for sale in 1964. Curious, I scattered the seed on a damp paper towel, rolled it up and sealed the roll in a plastic bag. I put the bag on top of my refrigerator where it stays moderately warm all the time.
After a week none of the seed had sprouted, so I concluded that 42 years of viability is too much to expect in a household environment. That said, one year of storage, in a place where your seed didn’t get too hot or too cold, shouldn’t have harmed them much. Do like I did and wrap some up in a paper towel. You will probably have more than 80 percent germination.