Seed Viability Chart: How Long Do Old Seeds Last?
Do you have a stash of old garden seeds? Same friend, same. But should we be hanging on to them?One of the most common questions I get around seed starting time is: How long do seeds last? Or, can I plant old seeds? The answer is usually yes, but within reason. Garden seeds become less viable over time, but the majority of seeds should still sprout and grow when they’re a few years old.
Several factors influence seed shelf life and viability, including the type of plant, if the seeds are pelleted or treated, and how the seeds are stored. This article will briefly explore each of these factors, along with frequently asked questions about using old seeds. I’ve also included a handy seed viability chart that shows the average shelf life of dozens of vegetable, herb, and flower seeds for easy reference!
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Do seeds have expiration dates?
Seeds do eventually lose their vigor and “expire”, but don’t often have an exact expiration date on the package. Rather, most seed packages include a sell by or packed for date – such as “packed for 2021”. That date simply represents the year that the seed company packaged and sold the seeds, not the year they need to be used by. Refer to the seed viability chart below to help determine their expected shelf life.
The first year sold, seeds will be at their utmost prime and will most closely follow the germination rate listed by the seed company (if one was provided). The germination rate signifies how many of the seeds successfully sprouted during trials by the seed company, and is usually expressed in a percentage (e.g. 85%).
How long do seeds last? Will old seeds still sprout (germinate)?
Seed viability depends on the type of seed, and just how old they are. Some old seeds will stay good and germinate for up to 5 years or longer, while others are only viable for a year or two. On average, old seeds will still sprout for about three to four years after their “packed for” date – especially if they’re stored in ideal conditions. Keep reading to learn more about seed viability by plant type and seed storage tips below.
As seeds age, their germination rate will decline. Meaning, fewer seeds will sprout compared to when they’re fresh and new. To compensate, we always sow a few extra seeds beyond normal when planting old ones. If you want to know if old seeds will sprout before planting them, you can perform a simple seed germination test. Learn how to test seed germination here.
Seed Viability Chart (shelf life by plant type)
The shelf life of old seeds varies greatly depending on the type of plant. Refer to the seed viability chart below to see the average shelf life of many popular vegetable, herb and flower seeds.
Certain vegetable seeds are notoriously short-lived (will only sprout for a couple years), such as onions, leeks, parsnips and spinach. Use those seeds up quickly, and plan to replenish your supply every couple of years! On the other hand, tomatoes, cucumbers, and many brassica seeds can stay good and germinate for up to 5 years or longer.
Similarly, most annual flower seeds are viable for about 1 to 3 years, while perennial flower seeds are usually good for 2 to 4 years. Yet there are always some rule-breakers in the bunch! For example, calendula is an annual flower (and one of my personal favorites) but it’s seeds can last up to 6 years or longer. Sunflower seeds also have a long shelf life.
Seed storage conditions and seed viability
How seeds are stored also greatly influences their shelf life. Ideally, seeds should be stored in dry, dark, and cool conditions to help seeds last as long as possible. Below 40% humidity is best. Warm humid conditions are the worst for seed storage. If seeds are exposed to moisture and become damp in storage, they may partially sprout or mold – effectively killing them.
Therefore, it’s especially important for folks in humid climates to store seeds in an airtight container, such as glass jars with tight-fitting lids. It may even be worthwhile to use silica desiccant packets inside the container if moisture intrusion becomes an issue. Some gardeners store their seeds in the refrigerator or freezer, though that becomes tricky for those of us with large seed collections!
We store our seeds in these handy storage cases, tucked inside a dark cool closet. With individual compartments and a sturdy handle, the containers serve multiple purposes: they keep our seeds dry, organized, easy to find and use! I can take the whole container out to the garden with me, or grab just the few small cases of the seeds I need. It also makes taking inventory for seed shopping a breeze. I absolutely LOVE this system!
Pelleted seeds shelf life
Pelleted seeds come with a white round biodegradable coating over the seed. They offer many benefits: they’re easier to handle and evenly space, and germinate better and faster. Pelleted seeds are especially handy for tiny seeds or those that are often surface-sown (and therefore prone to drying out) like carrots and lettuce.
Yet pelleted seeds have one major drawback: they have a significantly shorter shelf life than regular untreated seeds. So much so, most seed companies recommend using pelleted seeds within one year for successful sprouting.
Do old seeds grow weaker plants?
Yes, old seeds may produce less vigorous plants. Seeds that are just a couple years old should still grow to become perfectly robust plants, but as seeds get really old, both the germination rate and plant vigor can decline. Meaning, even if old seeds sprout, the resulting seedlings may grow more slowly or spindly, and plants that reach maturity may be less productive or yield less fruit. So if you’re ever gardening with old seeds and experience lackluster results, it might be time to get some new seeds!
What to do with old seeds?
Once you’ve decided to get rid of old seeds rather than try to grow them, you can simply compost them. Or, if you have backyard chickens like we do, sprout the seeds as a healthy chicken treat! Did you know that sprouts and microgreens are exponentially more nutrient-dense than the mature plants they’ll grow into? The process involves soaking a lot of seeds in a jar of water, so it doesn’t really matter if they all sprout or not. The chickens can eat the un-sprouted ones too. Learn how to make sprouted seeds for chickens here, including what types of seeds are safe to feed them.
And that’s the 4-1-1 on seed viability and planting old seeds.
I hope this answers all the questions you had about those old seeds you’ve been saving! Thankfully, you should be able to use them for a few years to come. Now don’t get me wrong, I love shopping for new seeds just as much as the next gardener… But considering most seed packets come with enough seeds to last the average home gardener many years, it’d be a shame (and quite wasteful) if those seeds were only good for one season! What are the oldest seeds you’ve ever successfully grown?
You may also like:
- 12 Places to Buy Organic, Heirloom and Non-GMO Garden Seeds
- Seed Starting 101: How to Sow Seeds Indoors
- 9 Common Seed Starting Mistakes to Avoid
- When to Start Seed: Planting Calendars for Every Growing Zone
- Using Grow Lights for Seed Starting or Indoor Plants
- Why and How to Grow Microgreens At Home
My papaw had a certain type of green bean seed he would plant. He passed away and my parents found his old bean seeds that were 20 years old in his shed. My mom planted them just to see if they would come up and they did. Not many come up but they were able to grow them and collect fresh seeds again.
Aaron (Mr. DeannaCat)
That’s a great story Amber, thanks for sharing!
I wish you had included cannabis seeds on your chart.
I store my c-seed in airtight plastic containers (e.g.; old 35mm film cannisters and the square containers that cannabis dispensaries sell their product in) and this has proven to be viable.
I do the same airtight storage for our food crop seeds.
Thank you for your excellent informational posts!
Wishing you and your a New Year of Good Health, Good Harvests, and Peace.
Aaron (Mr. DeannaCat)
Thanks for sharing Doug, we do keep our cannabis seeds sealed inside of a mason jar with a food desiccant and store them in the fridge. I think shelf life on cannabis seeds stored in the fridge is around 5-10 years while storing at room temperature may be closer to 2-5 years. Happy New Year to you as well and thank you for your support!
This was very helpful and informative. Thanks for taking the time to put this information together. I’m now going seed shopping for a few veg vareties that are most likely past their prime according to your chart and I’m not mad about it, lol. I love seed shopping!
Aaron (Mr. DeannaCat)
In regards to loving seed shopping, you and us both!