How long can you save seed?I have heard stories of gardeners using 8-year-old seed with a great deal of success.I have used seeds as old as 5 years old with varying degrees of success.My dad inherited an old coffee can of okra seed that was about 30 years old and had some of them germinate and grow for him.So how long are seeds really viable and how can you tell?Seed sales greatly increased last year nationwide.Seed catalogs seem to come earlier every year, and many gardeners already have a collection of them.Garden seed can be expensive, and you may want to consider using seed from previous years. Seed stores best if kept in a cold, dark, dry location. We normally consider seed will stay viable for about three years under these conditions though there are exceptions.For example, members of the carrot family (carrots, parsnips and parsley) are short-lived and are usually good for only one to two years.If you are unsure of viability and have plenty of seed, there is an easy method of determining how good your seed is. Place 10 seeds on a paper towel moistened with warm water and cover with a second moistened towel.Roll up the towels and place inside a plastic bag with enough holes for air exchange but not so many that the towels dry quickly.Place the bag in a warm place such as the top of refrigerator. Remoisten towels with warm water as needed.After the first week, check for germination. Remove sprouted seed and check again after another week.Add these numbers together to determine the percent germination.Scott Eckert is Harvey County Extension agent, horticulture.