Seed Storage and Viability

What does seed viability mean?

Viability is the share of seeds that are alive and able to sprout. Fresh seed from a reliable source usually has a high rate, which declines with age at a speed that depends on the crop and on storage conditions. Some seeds, such as onions and parsnips, are known for losing viability faster than many others, while seeds of some crops stay good for several years.

Because the rates vary, look up the crop in an extension seed-storage guide instead of relying on a general rule. Seed packets may also show a packed-for year or a sell-by date.

Keep notes on your own results. If your onion seed fails after one year while your bean seed is fine after four, you have a local rule of thumb that beats any chart.

What conditions keep seed alive longest?

Three things matter: dryness, cool temperature and darkness. Moisture is the biggest danger, since damp seed can mold or start to sprout, and warm temperatures speed the decline. Light and fluctuating temperatures also shorten life.

Aim for stable conditions. A closet in a cool part of the house is often better than a garage or shed that swings from hot to cold.

• Dry seed completely before storage.
• Keep it cool and steady.
• Use darkness: envelopes or opaque containers.
• Avoid damp basements and hot sheds.

Which containers work best?

Paper envelopes allow air movement and are fine for short storage in a dry place. For longer storage, put envelopes inside a sealed glass jar or a tight container with a lid that keeps out humidity and pests. Label each packet with the crop, variety and year.

Some gardeners add a drying agent to the container. If you do, follow the supplier's instructions, keep it from touching the seed and keep it away from children and pets. Check seed and containers a few times during the winter.

Avoid opening containers in a humid kitchen or on a rainy day. Moisture entering the container is the most common cause of early loss.

Should you refrigerate or freeze seed?

Cold storage can extend the life of many seeds, but only if the seed is truly dry and the container is sealed. Moisture in cold storage can damage seed, and condensation when a cold container is opened in a warm room is a particular risk. Let the container come to room temperature before opening it.

Ask your extension office whether cold storage suits the crops you grow, since methods differ. Keep the container where it will not be disturbed by repeated temperature changes.

Do not store seed in the freezer unless you have dried it carefully and sealed it well, and let the container warm up unopened.

How do you test germination?

Count out a set number of seeds, for example ten, place them between damp paper towels, keep them warm and check them over several days. Count how many sprout, and the share that sprouts is your germination rate. Choose a method from an extension guide for the crop, since some seeds take longer or need particular conditions.

If the rate is good, sow as usual. If it is low, sow more thickly to compensate, or replace the seed if the rate is very poor.

When should you throw old seed away?

Replace seed that has gotten damp, moldy, insect-damaged or that has a very low germination rate. Old seed that still sprouts can be planted, but the plants may be weaker and less uniform. For a crop where a failed stand costs you a season, such as one with a short growing window, it may be worth buying fresh seed.

Do not eat or feed seed that was treated, and dispose of treated seed as the label directs.

How do you plan your storage?

Keep seed in one place, organized by crop or by planting date, with a simple list that shows what you have and its age. This helps you use older seed first and avoid buying duplicates.

Make the storage space part of your yearly routine: check, test and sort every winter before ordering. That habit saves money and prevents empty rows in spring. Put a reminder on the calendar for a yearly storage check in winter. Open each container in a dry room, look for moisture, mold or insects and test the oldest seed. A few minutes at that time of year prevents most storage losses and tells you what to order.

Last reviewed: November 12, 2026. Written by the Homestead & Small Farm Editorial Team. See our editorial policy.