.jpg)
How Long do Seeds Last in Storage?
- Krista Green
- 2 days ago
- 5 min read
Updated: 2 hours ago
All of us gardeners love buying seeds (well, maybe not the paying-for part), but sometimes we can get a little overzealous. Or maybe we only plant a few seeds from a large packet and store the rest away. Over time, those leftover seeds begin to lose viability and produce poorer germination rates.
Some vegetable seeds last only one or two years, while others can remain viable for six years or more. You may have even heard stories of gardeners discovering their grandmother’s old tomato seed collection and successfully getting some of those seeds to sprout. While that’s not always the norm, it is possible under the right conditions.
Do Seeds Expire?
Estimating seed viability is just that—an estimate. There is no true expiration date stamped on seeds, and no rule that says a seed suddenly becomes useless after a certain year.
The goal here is to help you understand when it’s still worth planting old seeds and when it’s time to replace them, especially if you garden in a northern climate with a short growing season.
When seeds pass their suggested viability window, it doesn’t mean none of them will germinate. Instead, it usually means only 40–60% of the seeds are expected to sprout. If you choose to plant older seeds, simply sow two to three times more seeds than normal to compensate.
What Affects How Long Seeds Last?
Several factors determine seed storage lifespan, including moisture, temperature, light exposure, and seed type.
Moisture
Humidity is the number one seed killer.
Moisture can trigger seeds to sprout prematurely inside the seed coat. This internal sprouting is usually invisible to the naked eye, but once it happens, the seed is no longer viable for planting.
Moisture also encourages the growth of mold and bacteria, which can destroy seed viability and overall seed health.
Temperature
Temperature plays a major role in how long seeds remain viable. In general, cooler is better when it comes to seed storage.
Ideal temperature range for seed storage
Most vegetable seeds store best between 32–50°F (0–10°C). This is why basements and refrigerators work so well for northern gardeners.
Why heat shortens seed lifespan
Heat speeds up the natural aging process of seeds by increasing metabolic activity, even while dormant. Repeated temperature swings are especially damaging and can also cause condensation to form—leading back to the moisture problems discussed above.
Light Exposure
Seeds are meant to sprout after planting, not while sitting on a shelf.
Why seeds should be stored in the dark
Light can trigger chemical changes inside seeds that slowly reduce viability. While light alone won’t kill seeds quickly, long-term exposure—especially when combined with warmth—shortens their lifespan. Opaque containers or dark storage spaces are best.
Seed Type
Not all seeds are created equal when it comes to storage.
Oily vs. dry seeds
Seeds with higher oil content, such as onions and parsnips, tend to go bad faster because oils break down over time. Drier seeds, like tomatoes and squash, usually last much longer when stored properly.
How Long Do Seeds Last? (Seed Viability Chart)
One of the most common questions gardeners ask is how long do vegetable seeds last—and for good reason. Knowing this helps you decide which seeds to keep, test, or replace before spring planting.
Below are general estimates assuming decent storage conditions.
Short-Lived Seeds (1–2 Years)
These seeds should be replaced frequently, especially in northern climates where strong germination matters.
Onions
Parsnips
Corn
Leek
If you’re planting these past one year old, a germination test is strongly recommended.
Medium-Lived Seeds (3–4 Years)
These usually perform well for several seasons if stored correctly.
Beans
Beets
Brassicas (Cabbage, cauliflower, broccoli)
Carrots
Celery
Lettuce
Melons
Peas
Peppers
Spinach
Plant a little thicker as seeds age, especially with direct-sown crops.
Long-Lived Seeds (5+ Years)
These are some of the most forgiving seeds for storage.
Arugula
Tomatoes
Squash
It’s not unusual for well-stored tomato seeds to germinate even after 8–10 years.
Get Your Complete Printable Seed Viability Chart HERE
Have it sent straight to your email. I don’t send spam or share your information—just occasional helpful gardening tips.
How to Tell If Old Seeds Are Still Good
Short growing seasons don’t leave much room for guessing. If you’re wondering are old seeds still good, a quick germination test can save you time, space, and frustration.
The Germination Test
This is the most reliable way to check seed viability.
Step-by-step (beginner friendly):
Count out 10 seeds.
Moisten a paper towel (damp, not dripping).
Place seeds on one half and fold it over.
Put the towel into a plastic bag or container (leave slightly open).
Label with seed type and date.
Keep in a warm spot indoors.
Check daily and keep moist.
After expected germination days (this can normally be found on the seed packet), count how many seeds sprout.
What success rate is “good enough” to plant?
80–100%: Plant normally
50–79%: Still usable—plant thicker
Below 50%: Only worth trying with backups
Below 20%: Replace the seeds
For northern gardeners, strong early germination is especially important due to our short growing season.
If your seeds pass the germination test, the next step is starting them properly so they get a strong head start. You can follow my full seed starting guide here: https://www.zone3vegetablegardening.com/post/when-to-start-seeds-indoors
How to Store Seeds So They Last Longer
If you want to know how to store seeds long term, remember this rule: cool, dry, dark.
Best Containers for Seed Storage
Paper envelopes - Good for short-term storage and preventing trapped moisture.
Glass jars - Excellent for long-term storage. Add a silica packet or dry rice.
Airtight containers - Great for organizing multiple packets—only seal when seeds are fully dry.
Best Places to Store Seeds
Pantry - Works if your home stays cool and dry.
Basement - Often ideal in northern homes—watch humidity.
Refrigerator - Pros: Stable temps, long lifespan Cons: Moisture risk if not sealed properly
What to Avoid
Garages – temperature swings
Greenhouses – heat and humidity
Plastic bags without airflow – mold and bacteria risk
Not sure you’re storing seeds correctly? This guide walks you through it in more detail.
Frequently Asked Questions About Seed Storage
Can seeds last 10 years? Some can, especially tomatoes and squash, with excellent storage.
Should seeds be frozen? Only certain seeds should be frozen. These can sometimes include native seeds to northern gardeners. Refrigeration is safer for most gardeners.
Note: a cold period is sometimes needed to cause seeds to germinate. This is called stratification. You can read more here on what seeds require cold stratification.
Do heirloom seeds last longer? No—storage conditions and seed type matter more.
Do flower seeds last as long as vegetable seeds? Some last longer, some shorter—always test older seeds. Refer to my free printable seed viability chart (link below) to find viability dates for flower and herb seeds. Some last longer, some shorter—always test older seeds.
Final Thoughts: When to Keep Seeds and When to Replace Them
Not every old seed packet needs to be thrown away. Before tossing seeds, take a few minutes to test their germination. Even seeds that seem past their prime can sometimes surprise you. A simple germination test, like the one outlined above, is the best way to know for sure.
When starting seeds indoors, I always recommend using a reliable indoor growing setup to give seedlings a strong start. Pairing that with seeds from trusted seed companies can make a big difference, especially for northern gardeners with short growing seasons. Check out my other posts on indoor seed starting and choosing the best seeds for northern gardens for tips, tricks, and recommendations.
If you have found this article helpful and would like to see more gardening tips and tricks for gardening in Calgary and the surrounding area, please subscribe to my blog (the bottom of the home page) and follow me on Pinterest, Instagram, Facebook and/or YouTube!
