• SEED STARTING 101 •

seed viability: How long are your garden seeds good for?

As you curl up in a ball of happiness with your newly-delivered seed catalog, you might be wondering about how long your leftover seeds are good for. Seeds have a shelf-life as to how viable (able to germinate and grow) they are. In a nutshell, if a brand new seed has a 90% germination rate, that means 9 out of every 10 seeds sown should grow. Now, once that same seed is around three years old, the germination rate probably drops to around 60%, so that means that you’ll need to sow more of these older seeds to have a better chance of germination. 

Below is a listing of the approximate life span of vegetable, herb and flower seeds when stored properly. This is just an estimate, many seeds have been viable for much longer, while some a bit shorter. It’s best practice to do a quick viability test to check your germination rate prior to planting when using older seed.

Storage life of vegetable seeds:

Asparagus—3 years

Beans—3 years

Beet—4 years

Broccoli—4 years

Brussels Sprouts—4 years

Cabbage—4 years

Carrot—3 years

Cauliflower—4 years

Celery—3 years

Chard, Swiss—4 years

Chicory—4 years

Chinese Cabbage—3 years

Corn, Sweet—2 years

Cucumber—5 years

Eggplant—3 years

Endive—5 years

Kale—4 years

Leek—2 years

Lettuce—4 years

Melon—5 years

Mustard—4 years

Okra—2 years

Onion—1 year

Parsnip—1 year

Pea—3 years

Pepper—3 years

Pumpkin—4 years

Radish—4 years

Rutabaga—4 years

Spinach—2 years

Squash—4 years

Tomato—5 years

Turnip—4 years

Watermelon—4 year

Storage life of herb seeds:

Anise—5 years

Basil—5-7 years

Calendula—3 years

Catnip—5 years

Chamomile—3 years

Chives—1 year

Cilantro—5-7 years

Dill—3 years

Fennel—4 years

Lavender—5 years

Oregano—2 years

Parsley—1 year

Sage—3 years

Savory—3 years

Thyme—3 years

Storage life of flower seeds:

Ageratum—4 years

Alyssum—4 years

Amaranth—4 years

Aster—1 year

Baby’s Breath—2 years

Bachelor’s Button—3 years

Calendula—5 years

Celosia—4 years

Clarkia—2 years

Coleus—2 years

Columbine—2 years

Cosmos—3 years

Dahlia—2 years

Daisy—3 years

Delphinium—1 year

Dianthus—4 years

Foxglove—2 years

Geranium—1 year

Hibiscus—3 years

Hollyhock—3 years

Impatiens—2 years

Larkspur—1 year

Lobelia—3 years

Lupine—2 years

Marigold—2 years

Nasturtium—5 years

Nicotiana—3 years

Pansy—2 years

Petunia—3 years

Phlox—1 year

Poppy—4 years

Salvia—1 year

Snapdragon—3 years

Sweet Pea—3 years

Verbena—1 year

Zinnia—5 years

As a general rule, most annual flower seeds are viable for 1-3 years and perennial seed for 2-4 years.

Your seeds definitely may have a little more kick in them than this list says, especially if stored properly. 

The key to keeping your seeds viable for a few seasons is in how your store them. 

A few keys tips to seed storage success:

• Keep in a cool spot that offers a consistent temperature. Your best storage bet is to put your seeds in a sealed glass container (must be moisture-proof) and store in your freezer or refrigerator.

• Keep out of direct sunlight.

• Keep away from any humidity or moisture.

• Store in glass containers to help keep moisture and pests away. If you are storing in a sealed container like this, it is extremely important the seeds are 100% dry or mold will develop. You can even add some rice to the container to wick away any possibly moisture.

And good storage isn’t just long-term, it’s your every day use of your seed packets when you’re outside sowing. I’ve been guilty of forgetting a packet or two of seeds out in the greenhouse (or sometimes, even right out on a garden bed). What I learned the hard way was, that by doing that, I damaged their probability of germinating by exposing them to high temperatures, sun  and humidity.

There are a few other items that can come into play for certain seeds to be able to germinate:

• Light — Some seeds need light to germinate, while others need dark.

• Pre-soaking and Scarification — Some seeds have tough outer seed coats that can make it tough for the seedling to break through. To soften that outer cover, you can presoak the seed overnight. You can also use sandpaper or a knife to gently scratch the seed coat, scarifying it, basically creating an opening for the seedling to emerge through.

• Cold Treatment — Some seeds need to be exposed to a period of cold prior to being able to germinate. How cold and for how long, all depends on the plant. But most are easy enough to just be placed in the refrigerator for a few weeks prior to sowing.

Visit my FAVORITE VARIETIES to grow to see what’s growing on in my garden this year.

Up next in Seed Starting 101, What to Sow Indoors vs. Direct Sowing.