Garden of Eatin' / Seeds & Seedlings

How Long Do Seeds Last? (Plus a Cheat Sheet on Seed Life)

How long do seeds last? (Plus a cheat sheet on seed life)

The beginning of spring usually sees me sprawled in the middle of the living room floor, with all my ammo boxes, laying out rows and rows of seed packets sorted by vegetable, and then by variety.

Some are even color-coded… and I suddenly realize I have a rather strange obsession with collecting 12 different types of purple tomatoes (and counting).

Related: Grow the Best Tomatoes on the Block: 10 Tips for a Successful Harvest

Inevitably, a handful of seed packets get tossed in the compost pile as I double-check the dates… peppers from 2014, onions from four years ago. Yikes.

Some seeds I’ve only sown once or twice but still have half a packet left, some I’ve saved… and saved… and saved… because they’re so easy to save by the bagful every year (I’m looking at you, beans).

Others are rotated every few seasons as I try new varieties, and by the time I make it back to those Parisienne carrots, it’s already been a couple years.

Are they still good? Should I get new ones? How long do seeds really last, anyway?

I’ve combed through countless seed sites and extension sites over the years, wondering this very question.

So, how long do seeds last?

There seems to be no consensus, especially when you take into account the environment the seeds were stored in, the quality of the original crop the seeds were harvested from, and even the condition of the seeds themselves, as treated seeds will have a different lifespan than seeds in their natural state.

Seeds have a shelf life (as all living things do), and depending on where your particular shelf is, the viability of your seeds can vary by as much as a year or two.

When someone asks, “How long do broccoli seeds last?” a safe answer is three years, but in ideal conditions your seeds could still actually sprout after five.

So, you see where our dilemma lies.

Determining the germination rate of garden seeds

What are “ideal” conditions?

In a perfect world, we’d all have second refrigerators with perfectly controlled humidity levels in which to store our seeds.

Our seeds would live in this cool, dark, dry environment and 10 years later, those very first tomato seeds we’d ever bought would still be viable.

In reality, our homes go from hot to cold at the turn of the seasons, we sometimes forget our seed packets outside overnight (or at least I do), and an old shoebox will have to do for storage.

We can’t really fault ourselves either. Who knows what the seed went through before it even reached the store?

But here’s a proven fact.

Seeds store best below 40°F with less than 10 percent humidity, tucked inside airtight containers in a dark environment.

Every time a seed experiences less than ideal conditions, it suffers a decline in quality. It may not die right away, but it might take a little longer to germinate. Eventually, it will fail to germinate at all.

Using the baggie method with coffee filters (or paper towels) is a good way to test seed germination.

By taking a sample of 10 to 20 seeds and pre-sprouting them in baggies, you can gauge how viable those seeds are before committing to starting more of those seeds or transplanting the seedlings.

A good rule of thumb to know: less than 50 percent germination rate means it’s time to buy new seeds.

Then, there is the issue of seed vigor.

According to Oregon State University, vigor is the “ability of those seeds to produce normal seedlings under less than optimum or adverse growing conditions similar to those which may occur in the field.”

That is, the ability of your plants to survive in the ground outside with all the elements working against them (even if they’ve been hardened off), as opposed to being coddled inside in a cozy baggie.

Bean seed germinating
Bean seedling with great vigor
Above: A bean seedling that sprouted within days of being sowed. The cotyledons clearly look healthy and vibrant.

While a germination test can predict viability, it can’t truly predict vigor: how well a seedling will grow in terms of health, strength, uniformity, and root system, not to mention its production of flowers and fruits.

A seedling with compromised vigor may have a missing cotyledon, look stunted or scrawny, or seem overall slower to develop than seedlings from fresher seeds.

A bean seedling missing cotyledons
Above: A bean seedling (sprouted from a three-year-old seed) with missing cotyledons. This seedling will never develop into a normal productive plant.

Try as they might, sometimes older seeds just don’t have it in them to sprout, grow, and go all the way to seed again. A will to germinate does not equal an ability to thrive.

What the pros say about the average lifespan of seeds

The cheat sheet below takes the average life expectancy of seeds from a variety of sources, including the cooperative extensions of Oregon State University, Colorado State University, Purdue University, and Virginia State University.

Consider it more as a guideline, as the longevity of your seeds ultimately depends on the date on the packet and how carefully you’ve stored them since then.

Garden Betty’s Seed Life Cheat Sheet

Download printable chart
VegetablesShelf Life
Asparagus3 years
Beans3 years
Beets3 years
Broccoli3 years
Brussels sprouts4 years
Cabbage4 years
Carrots3 years
Cauliflower4 years
Celery3 years
Chard3 years
Chicory4 years
Collards4 years
Corn (sweet)2 years
Cress5 years
Cucumbers5 years
Eggplant4 years
Endive5 years
Kale4 years
Kohlrabi3 years
Leeks2 years
Lettuce3 years
Muskmelons5 years
Okra2 years
Onions1 year
Oriental greens3 years
Parsnips1 year
Peas3 years
Peppers2 years
Radishes5 years
Rutabagas4 years
Salsify1 year
Spinach3 years
Squash (summer and winter)4 years
Tomatoes5 years
Turnips4 years
Watermelons4 years
Herbs and FlowersShelf Life
Basil5 years
Chives2 years
Cilantro2 years
Fennel3 years
Oregano4 years
Parsley2 years
Sage4 years
Annual flowers1 to 3 years
Perennial flowers2 to 4 years
Download printable chart

This post updated from an article that originally appeared on March 17, 2015.

Linda Ly About Author

I'm a plant lover, passionate road-tripper, and cookbook author whose expert advice and bestselling books have been featured in TIME, Outside, HGTV, and Food & Wine. The No-Waste Vegetable Cookbook is my latest book. Garden Betty is where I write about modern homesteading, farm-to-table cooking, and outdoor adventuring — all that encompass a life well-lived outdoors. After all, the secret to a good life is... Read more »