Seed vitality or shelf life is an important concept. If you saved seed from last season or the season before or if you’ve been given seed and are not sure how long it’s been around, you might want to perform a seed vitality test a couple of weeks before you plan to sow.
Seeds more than a year or two old may not germinate well or at all, particularly if they have not been stored properly. Some seeds, even after a year of proper storage, may not produce the number of plants you expect or need.
To test your seed for germination, place two paper towels on top of each other and moisten them with warm water. Next place 10 or 20 seeds in the middle of the towels. Fold the towels over from the four corners to the center. Place the towels in a glass with about 1 inch of water in the bottom–enough to keep the towels moist without submerging the seeds. Cover the glass with clear plastic bag and set it in a warm place.
After the average number of days to germination, unwrap the towel and count the number of seeds that have germinated. If none have sprouted re-wrap the towel and replace it in the glass and wait several more days. If seeds have sprouted, count the number of sprouts and divide by the total number of seeds on the towel. That will give you a good estimate of the germination rate for that batch of seeds and the success you can expect when you sow in the garden.
Vegetable | Average rate of germination at 1 year (%) | Average years seed will germinate | Number of seeds per ounce | Average days to germination |
---|---|---|---|---|
Asparagus | 90 | 3 | 1,000 | 14-21 |
Beans | 90 | 3 | 90-100 | 6-15 |
Cabbage | 85 | 4 | 5,000 | 10-14 |
Carrot | 75 | 3 | 14,000 | 14-21 |
Cauliflower | 75 | 4 | 14,000 | 10-14 |
Corn, Sweet | 85 | 3 | 125 | 5-7 |
Cucumber | 85 | 5 | 1,000 | 7-10 |
Eggplant | 75 | 4 | 5,000 | 7-14 |
Lettuce | 90 | 6 | 12,000-16,000 | 7-10 |
Muskmelon | 85 | 5 | 1,200 | 6-10 |
Mustard | 85 | 3 | 18,000 | 8-12 |
Okra | 85 | 1 | 425 | 10-14 |
Onion | 80 | 2 | 12,5000 | 7-14 |
Parsnip | 85 | 1 | 600 | 21-27 |
Pea | 90 | 3 | 50-150 | 7-10 |
Pepper | 75 | 2 | 4,000 | 10 |
Pumpkin | 90 | 4 | 100 | 7-10 |
Radish | 90 | 4 | 5,000 | 4-6 |
Spinach | 80 | 3 | 3,000 | 8-12 |
Tomato | 85 | 3 | 6,000-7,500 | 5-7 |
Turnip | 90 | 4 | 10,000 | 7-10 |
Watermelon | 85 | 5 | 175-225 | 6-8 |