Seed Viability

For many dedicated gardeners the 1995 gardening season is well under way. They began germinating their slow growing seeds in early- to mid- January. For many garden seeds, 8 weeks before the last frost will provide transplants of optimal size. Because many of our gardens are smaller than in the past, we often have seeds leftover from year to year. A commonly asked question is how long will the seeds remain viable?

Much of seed viability depends upon storage conditions. The ideal storage condition for seeds is somewhere cool and dry. For many homeowners a capped jar in the refrigerator serves the purpose. Just looking at the seed will often give an indication of seed quality. For seeds that are usually smooth and round or plump, they will not germinate well if they are pocked or wrinkled. Peas, corn, and many other seeds are normally wrinkled but may not look as good as they should.

If you are unsure of the seed quality, you can run a germination test. Count out at least 20 randomly picked seeds (50 is better, 100 is best). Spread the seeds on several layers of premoistened paper toweling and roll them up in the paper so the seeds stay separated from one another. Place the roll into a plastic bag and keep it in a warm place (70o to 80o F). Remember to label each roll with seed type. Check the seeds in two or three days, and every day thereafter for a week or so. When a root or cotyledon protrudes through the seed coat, the seed has germinated. When some seeds have sprouted, and a one-week wait indicates that no more are about to emerge, you can calculate your rate of germination. Divide the number of seeds germinated by the number of seeds tested to find out your germination percentage. If handled very carefully, germinated seeds may be planted in the garden (if the planting time is right) or in cell packs and peat pots for further growth. If the root or shoot is damaged in the transplanting process, the plant will not survive.

How long will vegetable seeds last if stored properly?

Seed Type Years Seed Type Years
Asparagus 3 Muskmelons 5
Beans 3 Onions 1
Beets 4 Peas 3
Broccoli 5 Peppers 2
Cabbage 5 Pumpkins 4
Carrots 3 Radishes 5
Cauliflower 5 Spinach 5
Corn 2 Squash 4
Cucumbers 5 Tomatoes 4
Lettuce 5 Watermelons 4

If you have some seed left from past gardening seasons, you may not have to buy new this year. Reflect upon the storage conditions, visibly inspect the seed, and run a germination test to check the seed viability. You may end up having extra money in your gardening budget to buy additional seeds.

This article originally appeared in the March 3, 1995 issue, p. 16.

Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on March 3, 1995. The information contained within may not be the most current and accurate depending on when it is accessed.