How Long Do Vegetable and Herb Seeds Last?

Are my seeds still usable? It’s a frequent garden question. Here’s a quick reference guide for the average lifespan of common vegetable seeds

Old seeds? Find out which seeds are still good and which you should toss.

We’ve all been there – you have half-used packets of seeds from last year, some seeds you saved from vegetables (or flowers) from the garden a couple of years ago, or maybe some seeds a friend gave you. But how do you know if they’re still any good?

Well, it depends.

There are lots of factors that affect the viability of seeds, but the two big ones are the type of plant and the age of the seeds. As long as you kept the seeds dry and didn’t expose them to high heat, all seeds should be good for a year or two. After that, seed germination rates start to drop off. Here’s a general guide for how long seeds keep fresh:

• 1-2 YEARS:
  onions (including chives, garlic, leeks, and onions), parsley, parsnip, and rhubarb
• 2-3 YEARS:
  beans, corn, peas, peppers, and spinach
• 3-4 YEARS:
  asparagus, carrots, celery, kohlrabi, summer squash and zucchini
• 4-5 YEARS:
  brassicas (including broccoli, brussels sprouts, cabbage, cauliflower, mustard, and radishes), pumpkin, tomato, and winter squash
• 5+ YEARS:
  cucumber, endive, lettuce, and melons

How Long Seeds Typically Last (Seed shelf life)

Here is a more detailed chart of typical seed shelf life. Keep in mind that these numbers are an estimate and that variables like heat, water, and light affect seed viability. It’s always best to store seeds in a cool, dry place away from light.

*Based on my experience. Your mileage may vary.

How to Tell if Seeds are Still Good

Commercial seed packets have a “packed for” date on them. This isn’t an expiration date, but the planting year for which they were packaged. So, if you buy seeds that have “packed for 2024” on them, they were probably grown in 2023, making them a year old by the time you get around to planting them.

Commercial seeds will have a date with the year the seeds were packed for

On the other hand, if you have home-collected seeds, the date on the container (you remembered to date the container, right?) is when they were collected, not the year they were supposed to be planted.

Either way, it’s not a big deal as long as you keep in mind that your seeds are at least a year old as you’re going through them. Most will be okay for 2-3 years after their packing date, but the germination rate will decline steadily the older they get (onions are especially short-lived). So, if you’re sowing seeds that are more than a year old, you’ll probably want to sow a few extra to make up for the ones that are no longer viable.

Seed Testing

If you really want to know whether the seeds are viable before you try planting them, you can do a germination test using a few seeds and a damp paper towel. Just get a paper towel, wet it and place about 10 seeds you’d like to test on it. Fold the towel over and put it somewhere dark and room temperature (a linen closet or under the sink works).

After about a week, check the paper towel to see how many seeds have sprouted. Assuming you tested 10 seeds and 7 of them sprouted, your seeds then have a germination rate of 70%.

Personally, I don’t do germination tests because I rarely have enough leftover seeds to waste on a test. I’ll just plant them in seed trays and see what sprouts.

How to Store Seeds for Maximum Shelf Life

Seeds last longest when they’re stored in a dry container, a cool place (i.e., below room temperature), and away from sunlight. Personally, I like Altoids tins and old medicine bottles, but paper packets like the ones the seeds come in or plain old coin envelopes work well too.

I like to use old Altoids tins and medicine bottles for my seed storage

I’ve seen some people use airtight containers and/or store their seeds in the refrigerator, but I think those are overkill (nature doesn’t store her seeds that way). As long as the seeds don’t get damp and exposed to light they should have a long shelf life.

What To Do With Old Seeds

Since old seeds won’t germinate, there’s no problem with throwing them in the compost pile or green waste bin. You can even till them back into your garden beds where they’ll release what nutrients still remain back into the soil.

Personally, because I have chickens, and they love to scratch around, I’ll just toss the old seeds to them and let them have at it. A lot of times I’ll throw them into a freshly emptied compost bin and let the chickens scratch at them there. They turn the soil and the fresh chicken poop will give the next pile of compostable materials a kick start.

My chickens working the compost

Conclusion

As a seed hoarder myself, I know it can be a struggle to get rid of old, past their prime seeds. But in the end, clearing out the seed collection is rather refreshing as it gives you a better idea of what you have available and what you need for your next garden.

Sometimes, however, I do admit that I’ll try and sprout some really old seeds either because that plant isn’t available anymore, or I just want to see if they’ll grow. Most of the time they don’t do anything and I re-use the potting soil for something else. But once in a while a couple do sprout and I have the satisfaction of knowing that those seeds I saved 10 years ago are making plants today. It feels pretty good.