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how old can seeds be and still germinate

How to Know If Garden Seed Is Viable

I have old packets of seeds. How can I tell if they are still viable?

Answer: Most seeds last for several years, however others have a relatively short life. How do you know if your seeds are still viable? When properly stored in a cool, dry place, seed’s shelf life can be extended. Yet, even then, there is no guarantee that they will still be productive for next season’s planting. There are two easy tests you can take to check to see if there is life left in your old seeds.

Water test: Take your seeds and put them in a container of water. Let them sit for about 15 minutes. Then if the seeds sink, they are still viable; if they float, they most likely will not sprout. This method, in my opinion, is not the best way to check your seeds. For surer results, try performing a germination test.

Germination test: Take some of your seeds, preferably 10, and place them in a row on top of a damp paper towel. Fold over the paper towel and place in a zip-up plastic bag and seal it; this helps to keep the towel moist and protected. Then put in a warm location, like a high shelf or on top of the refrigerator, and check the seeds often—around once a day—to see if they have began to germinate and/or to check the moisture of the paper towel. If it needs more water, carefully mist the towel to where it is damp, but be careful not to apply too much water. Make sure the location you have chosen is away from exposure to direct sunlight. This can overheat your seeds.

Your seeds should begin to germinate in several days up to a couple of weeks, depending on the seed-type. A good rule of thumb is to wait roughly 10 days; however, if you want to give your seeds the best chance, research the germination time of your specific seeds. Once the allotted time has passed, check to see how many have germinated. If you placed 10 seeds on the paper towel, this will be pretty easy to calculate. If less than 5 seeds sprouted, your old packet may not have much success when it comes to planting. If more then 5 sprouted, than your seeds still have a lot of vigor left in them!

Some people wait to perform this germination test around the time of planting, so that the successfully sprouted seeds can be placed directly in their garden—a good way to cut time and ensure the plants will flourish beautifully outdoors.

No matter what step you take to test the viability of your seeds, always remember that every seed is different and your results may vary. With success, you can help your little seedlings sprout into the magnificent, thriving plants they were meant to be.

Image: Jeffdelonge
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If you have an old packet of seeds, here are some ways to determine if it is worth planting.

Can Old Vegetable and Flower Seeds Still Be Planted?

The Spruce / Lacey Johnson

Seed packets you purchase often contain more seeds than you can plant in one season, and over time you may have many partial packets of seeds without knowing just how old they really are. You might rightly wonder if they will germinate (sprout) again if you plant them. Do seeds go bad with time, or can you plant them no matter how old they are?

The answer is, yes, seeds will eventually go bad and no longer germinate, but it can take quite a long time. There is a good chance that those old seed packets will have a high percentage of seeds that will germinate just fine. Most seeds, though not all, will keep for at least three years while maintaining a decent percentage of germination. And even a group of very old seeds may have 10 or 20 percent that still sprouts.

Proper Storage

Your old seeds will stand the best chance of germinating if they have been stored correctly. All seeds will store most effectively in cool and dry conditions, so you should be wary of any seeds that are stored in opposite conditions—warm and moist. When you examine seeds, discard the entire packet if they show signs of mold or another fungus.

Many commercial seed packets may have a “use by” date printed on them. Don’t take this date too seriously—the seed manufacturers use this date to ensure that customers experience a large percentage of germination, and many seeds may remain viable for many years after the date printed on the packet. But the printed date will give you a sense of how old the seed packet is. If you are only a year or two beyond this date, there’s a good chance most of the seeds will still germinate when planted. But if the seed pack is six years old or more, expect to have a much lower percentage of germination.

Going forward, proper storage procedure is to date the seed packet when you buy it, to ensure that you’ll know exactly how old it is when you reach for it in the future. If possible, store the seeds in a sealed plastic bag containing a desiccant packet (those small packets that often come in over-the-counter medicine products), which will keep the seeds dry. If you don’t have desiccant, packets of dry rice or powdered milk will also absorb air moisture. The sealed seeds can be stored in the refrigerator or another cool place, but don’t freeze them.

Average Shelf Life of Some Common Seeds

Here are some estimated shelf life figures from Oregon State Cooperative Extension, based on research. Be aware, though, that even in seed packets much older than this, some of the seeds may still sprout.

  • Bush and pole beans: two years
  • Beets: two years
  • Broccoli:
  • Brussels sprouts: three to five years
  • Cabbage: three to five years
  • Cauliflower: three to five years
  • Carrots: three years
  • Collard: three to five years
  • Kale: three to five years
  • Kohlrabi: three to five years
  • Corn: one year
  • Cucumbers: three years
  • Leeks, onions: two to three years
  • Lettuce: three years
  • Melons: three years
  • Oriental greens: three years
  • Parsley: two years
  • Parsnips: one year
  • Peas: two years
  • Peppers: two years
  • Radishes: four years
  • Rutabagas: three years
  • Spinach: one season
  • Squashes: three to four years
  • Swiss chard: two years
  • Tomatoes: three years
  • Turnips: four years
  • Annual flowers: one to three years
  • Perennial flowers: up to four years

Is There a Way to Test Seeds for Viability?

Seeds gradually lose viability as they age, so a packet that begins with a 90 percent viability rating on the packet may, after three or four years, have a much lower viability rate. A simple seed viability test, done by placing a small group of seeds on a damp paper towel to see how many sprouts, can tell you roughly how many of the seeds in the packet will be viable when planted.

If you have a group of seeds you’re not sure about, you can still plant them, but space them with greater density than you would for fresh seeds. Even if only 30 or 40 percent of the seeds germinate, you can still have a successful planting.

Can I Save My Own Seeds From the Plants I Grow?

Saving and starting your own herb, vegetable, and flower seeds is a great way to garden for just pennies each year. Be aware, though, that seeds collected from hybrid plants may not “come true” from the seeds produced. You can still save the seeds, and those seeds will still sprout into seedlings, but it is likely that the mature plants will demonstrate different characteristics than the plants from which you took the seeds. This is because hybrid plants are created by cross-pollinating different parent varieties, and their seeds do not carry the full genetic information. This isn’t always a bad thing. You may actually find that tomatoes from saved seeds, for example, are tastier than the hybrids, although they may not look as perfect. Flowers seeds saved from hybrid plants may produce some unusual and interesting offspring.

If you save seeds from vegetables and fruit you grow yourself, store them in the same way that you save seed packets—in dry and cool conditions.

Learn how to save your seeds for future planting to save pennies in your garden, as they can last many years before losing viability.