Using old garden seed

I rarely use an entire packet of vegetable seeds every year. Garden seed gets expensive so I hang onto them, thinking I’ll use them again the next year but I’m never sure if they’ll still germinate.

Ward Upham is an Extension horticulturist at Kansas State University. He says a packet of seeds will generally last three-to-four-years, but there are exceptions.

"For example, if you have onions, they are very short-lived, they will last about a year so you can plant them this year and then next, and that’s probably about it. Also things like carrots and parsnips, and parsley, maybe 1-2 years, corn and peppers maybe two-years," says Upham. "For most the other stuff it’s going to be a good three-years, some seed will last as much as five."

If you’re unsure of viability and have plenty of seed, there is an easy method to determine how good it is. Upham says to roll up 10-to-20-seeds in a moist paper towel, and put them in a plastic bag with a few holes for air. The bag needs to sit in a spot that’s 70-to-80-degrees. The top of the refrigerator is usually a nice warm place.

After about a week, check to see how many seeds have germinated.

"Pull those germinated seeds out, roll them back up, make sure that paper towel remains moist, and then check them after another week. And then, you can figure out what your germination percentage is," he says. "Some people say as low as 50% you can actually still use the seed, just sow it twice as heavy. I actually prefer probably closer to 75%. If you have 75%, just assume that seed’s good, and you’ll be fine."

You may have better luck with seed longevity if they’re stored in an air-tight container, in cool, dark, and dry conditions. Upham says one the easiest ways to do that is to put your seed packets in a canning jar and keep them in the fridge.