How many times have you opened a seed packet you saved from the previous year (or two…or three…) and wondered if you could plant them this year? Well, you can plant anything – the question is, will the seeds germinate and grow?
The answer is “maybe”. Some vegetable and herb seeds can be saved for up to 6 years under the proper conditions. Other garden seeds will only last 1-2 years. But that phrase “proper conditions” is key. If you leave your garden seed packets on a windowsill all year the seeds will not stay viable. If you store them properly as outlined below, there’s a good chance of using the same seed stock for multiple seasons.
How do I know if my garden seeds are still good to use?
Viability refers to a seed’s ability to produce a vigorous seedling. This means a seedling that will grow to full maturity and bear its intended fruit (in the botanical sense – the fruit, vegetable, flower, herb, etc). Seed viability declines before the germination rate does, so if the seed stock is old or if it’s not stored properly, the seeds may germinate but produce weak seedlings that die after days or weeks.
Sometimes you can see right away that a seed is past its prime. For instance, if the seed is normally round in shape, but now has indentations or divots, it’s probably not viable. See our post about how to test garden seeds for viability.
What is the proper way to store garden seeds?
To save garden seeds and keep them viable, you need to remember two words: cool and dark. If the seeds are exposed to moisture (water or humidity) and warmth, they won’t remain viable and their germination rate will plummet.
Seeds should be stored in their original packets or in a glassine envelope. That packet or envelope should then be placed in an airtight container in a cold room or in your refrigerator, but never let them freeze. To be specific, the perfect storage temperature for most varieties is 45 degrees Fahrenheit at 40% humidity. The rule of thumb is that the sum of the temperature and humidity should be less than 100.
My personal method, while a bit loosey-goosey, has served me well. Every packet of garden seeds is stored in its original envelope inside an airtight mason jar. To keep humidity very low inside the jar, I add a packet or two of standard-issue desiccant like silica gel – the little packets sent in shipments of food, athletic shoes, and other products. I have many mason jars of garden seeds and they all get stored in a plastic storage bin in a cool garage with no cars (exhaust fumes can kill seeds). The bins stay in the garage fall through late spring and are moved to the coolest room of the house in summer. I would store them in the refrigerator (this is the proper way), but I have too many jars of seeds… and a wife. Overall, this method has served me very well and I’ve kept seeds on average a year longer than the years shown in the seed viability table below.
How long do garden seeds last?
Garden seeds can be stored for years under the right conditions. Even though celery typically stays viable up to 5 years, I’ve been using the same seeds for 7 years – the germination percentage has decreased, but that’s a pretty good run. The actual storage life always depends on the viability of the variety, the seed stock itself, the moisture content of the seed when it’s initially placed in storage, and the conditions under which it’s stored.
How to test your garden seeds for viability
- Dampen or mist a plain white paper towel, fold it in half, and place a few seeds on one half.
- Then fold the paper towel in half again over the garden seeds and place it in a plastic bag. If you use a zip-lock type bag, leave it open a little bit so the seeds can get oxygen, which is necessary for germination. Note the variety of seeds and the date you started the germination test.
- Place the plastic bag in an environment appropriate for seed germination. Generally, this means 70-80 degrees with some light (some varieties will differ).
- Check the seeds each day for germination and re-mist the paper towel when necessary to keep it damp.
- After 3-10 days, most varieties of seeds will have germinated. More time may be required for varieties like celery or strawberries or if the seeds are old.
- You can plant the germinated seeds directly in your garden or in pots to get the seedlings established.
- Test your germination percentage to determine how many seeds in the remaining stock will germinate: Divide the number of seeds that germinated by the number of seeds tested. If the germination rate is under 70% your seed stock is considered unreliable and is on its way out.
It’s even easier to test the viability of peas – just place them in a bowl of water. If they float they’re sterile; if they sink they’re viable. The ones that float no longer contain an embryo and so are lighter than those that do.
Vegetable and Herb Seed Viability
These are rough estimates of how long a seed will remain viable. Proper saving methods and storage conditions can extend a seed's life considerably.| Seed | Viability in Years | Seed | Viability in Years | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Artichokes | 5 | Lavender | 4 | ||||||
| Arugula | 3 - 4 | Leek | 2 - 3 | ||||||
| Asian Greens | 3 | Lemon Balm | 1 - 4 | ||||||
| Asparagus | 3 | Lemon Grass | 1 - 3 | ||||||
| Basil | 3 - 5 | Lentil | 1 - 2 | ||||||
| Bean | 3 | Lettuce | 1 - 6 | ||||||
| Beet | 4 | Lovage | 1 - 3 | ||||||
| Borage | 1 - 4 | Marjoram | 1 - 4 | ||||||
| Broccoli | 3 - 5 | Melon | 3 - 6 | ||||||
| Brussels Sprouts | 4 | Mustard | 4 | ||||||
| Cabbage | 4 - 5 | Okra | 2 | ||||||
| Carrots | 3 | Onion | 1 | ||||||
| Cauliflower | 4 - 5 | Oregano | 4 | ||||||
| Celery | 5 | Parsley | 1 - 3 | ||||||
| Chamomille | 4 | Parsnip | 1 | ||||||
| Chinese Cabbage | 3 | Pea | 2 - 4 | ||||||
| Chard | 4 | Pepper | 2 - 4 | ||||||
| Chicory | 4 - 5 | Pumpkin | 4 | ||||||
| Chives | 1 - 2 | Radish | 5 | ||||||
| Cilantro | 5 | Rhubarb | 1 - 2 | ||||||
| Collards | 5 | Rosemary | 1 - 4 | ||||||
| Corn | 1 - 2 | Rutabaga | 3 - 5 | ||||||
| Cress | 5 | Sage | 1 - 3 | ||||||
| Cucumber | 5 | Savory | 1 - 4 | ||||||
| Cumin | 1 - 4 | Spinach | 1 - 5 | ||||||
| Dandelion | 1 - 2 | Squash | 4 - 5 | ||||||
| Dill | 5 | Strawberry | 5 | ||||||
| Eggplant | 4 - 5 | Thyme | 1 - 4 | ||||||
| Endive/Escarole | 5 | Tomato | 4 | ||||||
| Fennel | 3 - 4 | Turnip | 5 | ||||||
| Kale | 5 | Watermelon | 5 | ||||||
| Kohlrabi | 3 - 5 | Winter Squash | 4 |
Great article! Now I wish I can save your seed viability table.