Can Garden Seeds Be Saved From One Year to the Next?

Longevity and Optimum Conditions

• Most seeds will not reach the 10-year mark, but many can remain viable for one to five years. Others, such as the seeds of asparagus, geranium, delphinium and salvia, can't be saved beyond the first year no matter how carefully they are stored. The more long-lasting seeds include beet, cucumber, eggplant, muskmelon and tomato. Assuming you're starting with high-quality seeds, the two factors that have the greatest impact on whether the seeds will store well are moisture and temperature. Instead of the warm, moist conditions that a seed needs for germination, those to be stored must be kept dry and cool.

Drying

• Attaining the maximum longevity for stored seeds requires a moisture level of no more than 8 percent. To obtain that degree of dryness, spread the seeds on a flat surface where the temperature is greater than 70 degrees Fahrenheit and let them dry for several days. If the seeds have been exposed to humid conditions, you can dry them in a conventional oven at 100 degrees Fahrenheit for six hours with the oven door open. Check the seeds frequently to avoid overdrying, which can result in hard seeds that are unable to absorb enough moisture to germinate. To gauge whether or not small seeds have reached the right moisture level, attempt to bend one. If it snaps cleanly in half, it's ready for storage. Larger seeds, such as corn, peas and beans, should shatter if you hit them with the head of a hammer if they're dry enough.

Waterproof Storage

• Store dried seeds in a moisture-proof container such as a Mason jar with a new lid or a heavy-duty plastic bag with a tight-sealing closure. Use lightweight plastic bags only for separating varieties of seeds inside a jar or heavy plastic bag. Place a desiccant (drying agent) such as powdered charcoal, silica gel or calcium chloride in the bottom of the container to remove any residual moisture. Place the seeds in a plastic bag to keep them from coming in contact with the desiccant. You can use rice or powdered milk to absorb moisture, but wrap powered milk in two layers of paper towel to keep it from dissolving.

Cold Storage

• Store seeds in their moisture-proof containers at a temperature below 75 degrees Fahrenheit. For long-term storage, place the containers in a refrigerator or frost-free freezer. If seeds have been dried properly, freezing won't harm them. Let them warm to room temperature before handling the seeds after you remove them from storage.