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how to germinate old seeds

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.

Four Hacks for Germinating Old Cannabis Seeds

When your old cannabis seeds don’t want to pop, one of these four techniques could come to their—and your—rescue. Aging seeds are more difficult to grow than fresh ones and we’ll explain what you can do to help germination.

The older a cannabis seed gets, the harder it is to pop. But hard doesn’t mean impossible. If you’ve been saving your seeds for a rainy day and it finally started pouring, these tips could help you get most, if not all, of your old beans to germinate.

1. PRE-SOAK WITH SUPPLEMENTED WATER

As cannabis seeds age, their protective outer shell hardens and prevents water from passing through. Unless the tiny, dormant embryo that lives inside the shell detects moisture, it doesn’t know that the conditions are right to sprout. As a first step, pre-soak your old cannabis seeds for about 12 hours to see if that does the trick.

To improve your chances, use carbonated water and/or add one of these supplements that help with water absorption. Fulvic acid and most boosters also give your seeds a light dose of nutrients.

  • Fulvic acid
  • Germination booster
  • Hydrogen peroxide
  • Gibberellic acid

Keep the water warm, but not too hot. Aim for around 22°C. Avoid direct sunlight, and keep an eye on the glass. Do not soak seeds for prolonged periods, more than 24 hours can deprive them of oxygen and make them drown.

2. SCARIFICATION

Scarification, or scuffing the shell, can also help water pass through an older seed’s tough outer shell.

To scarify your seeds, line a matchbox or other small container with sandpaper. Drop the seeds inside, shake vigorously for 30–60 seconds, then remove. You may not notice much of a difference, but the small micro-abrasions are sometimes enough to let water breach the shell and trigger germination.

3. REMOVE THE RIDGE

The seed’s shell is made up of two pieces, with a seam going all around. The side that’s raised more than the other is the ridge. A hardened ridge can make it difficult for the seed to open. To remove the ridge, run a sharp blade along the ridge on both sides. Handle gently and it should come off without damaging the inside of the seed.

Removing the ridge not only makes it easier for the seed to open, it helps with water absorption.

4. SLICE THE SEED

In a life or death situation, surgery may be the only option. Meaning—only do this if nothing else has worked because this technique ruins as many seeds as it saves.

  • Remove the seeds from any moisture and allow them to dry out completely.
  • Use a sterile scalpel to slice into the seed at the seam and open it slightly.
  • Try to germinate it again.

THINGS TO REMEMBER

If you’re going to keep seeds more than a year or two, proper storage will dramatically increase the chances of late-stage germination. Place them in an airtight container. Put the container in a refrigerator set at 6–8°C with 20–30% relative humidity. If excess moisture is a concern, add silica gel packs to the container.

As you proceed through these steps, the risk of damaging your seeds past the point of recovery increases. Between each suggestion, give them a few days to a week to germinate. Allow the outside to dry each time to prevent rot. Do not try all or multiple techniques at once.

In the future, consider growing your seeds before they get a chance to get old. They’re not cheap, so letting them go bad is a waste in all kind of ways.

As cannabis seeds age, germination success rate decreases with each passing year. Use these tips to revive your old beans.