The age-old question, do plant seeds expire or go bad? The answer isn’t as easy as a simple yes or no. While yes, there is an expiration date on the new seeds you picked up from the local garden store, they don’t technically expire. Can they go bad? Absolutely but let’s explore.
The first time I purchased garden seeds from the store, I saw the expiration date and threw my seeds away the second that date came and went, purchasing new seeds again the next year. Now, I realize how foolish that was. But as a new gardener, I didn’t know. I’ve been conditioned by the food industry to toss items once an expiration date has been reached. But seeds are not yogurt.
Do Plant Seeds Expire?
Seeds do not have an expiration date. The expiration date on a seed packet is a sell-by date. Seed companies must put a sell-by date on their packages to ensure consumers aren’t taken advantage of and are provided fresh seeds yearly. The expiration date on a packet is helpful when you have leftover seeds and are trying to judge how old they are, but it tells you nothing about the seeds’ viability.
Even though seeds don’t expire and can germinate well past their expiration date, you’ll get the best germination rate from vegetable seeds that started before that date. So try to use your seeds before the expiration date, but don’t worry about it if you don’t.
Do Seeds Go Bad?
While seeds don’t expire, seed viability does decline as time passes. Seeds aren’t meant to be tucked into seed packets or stored in jars. Think about how a seed works. It drops from a plant and often lies dormant over the winter months waiting for the right conditions to begin sprouting. This typically happens within the one year window. Seeds just don’t want to lie in wait year after year.
Some varieties tolerate a longer dormancy period than others. For example, I always purchase new onion seeds even if I have some leftover from the year before. Onion seeds have a high germination rate before the expiration date. The germination rate for this seed type significantly declines for older seeds.
Seeds can also go bad, especially when they aren’t properly stored. Seed storage is so important to keep old seeds viable. To keep seeds healthy, they should be stored in a cool, dry, dark place, preferably in airtight containers. Extra emphasis on a dry place with low humidity. These conditions will help keep seeds dormant and prevent them from becoming moldy.
The general rule of thumb to extend the shelf life of seeds is to store seeds properly. So do seeds go bad? Sometimes.
How Long Do Seeds Last?
Below are some general guidelines for seed longevity across different types of seeds. These aren’t hard and fast rules, but some general guidelines from the Farmer’s Almanac. The Almanac’s information came from research from Colorado State University Extension. I also share some of my experiences on how long are seeds good for as a zone 5a gardener with over 15 gardening seasons under my belt.
Replace After One Year
Lettuce Seeds
While the Farmer’s Almanac says to replace lettuce seeds after a year, my experience says not all lettuce seeds are created equal. Some varieties germinate great up to five years. Others need replacing every year. For me, I wait until I start noticing poor germination before I toss a lettuce packet.
Onion Seeds
Onion varieties, including leeks and chives, rarely germinate well after a year. I’ll never forget the year I missed starting my shallot seeds. I saved them to start the following year. Out of about 100 seeds sowed, maybe four germinated. Now I never save last year’s onion seeds.
Parsley Seeds
This category also includes cilantro and dill seeds. They don’t last very long. If I still have some leftover, typically I’ll overseed them the next year instead of buying more seeds. If you do this, expect slightly lower germination rates in year two.
Parsnip Seeds
Parsnip seeds are like onion seeds in my garden and are a type of plant seed that rarely germinates well if not used within the year. I tried sowing an old packet of seeds a couple of years ago with very poor results, about a 40% germination rate.
Replace After Two Years
Corn Seeds
It is recommended to replace corn seeds after a couple of years. In the past, I got relatively good seed germination rates for corn in years 2 and 3 before the rate plummets. Because corn is such a large plant, I’ll often start way more corn than I need in soil blocks so I can transplant them perfectly in a corn grid and not worry about germination rates as much.
Okra Seeds
Being in a northern climate, I don’t have much experience with heat-loving okra. Generally speaking, they are good for one to two years.
Pepper Seeds
While the recommendation for peppers is to replace after two years, I’ve experienced excellent germination rates up to five years before it starts dwindling. Although occasionally, different seeds yield different results. I do germinate my pepper seeds with a heat mat and some direct sunlight from a south-facing window, which might skew my results. Pepper seeds at room temperature often take longer to germinate and have a low germination rate.
Replace After Three Years
Asparagus Seeds
Chances of successful germination of asparagus seeds start to dwindle after three years. I’ve only used new asparagus seed packages and don’t have any experience with older seeds.
Bean Seeds
Old bean seed packets germinate well into their third year and just want to grow. While the germination rate does go down in later years, I’ve found older bean seeds germinating for a long time after that three year mark.
Broccoli Seeds
Generally speaking, from my experience, broccoli seeds and the rest of the brassica family (including cabbage, kale, brussels sprouts, and more) germinate well until about year four or five. The Farmer’s Almanac recommends replacing after the age of the seeds hits three years.
Carrot Seeds
The Farmer’s Almanac recommends replacing carrot seeds after three years, but I would recommend after year two. Or better yet, try to use all your carrot seeds each year. I’ve noticed about a 20-25% decrease in germination after year one and even higher after year two. While not as significant a decline as onions, carrot seeds have a shorter lifespan.
Celery Seeds
Celery seeds should be replaced after three years. I generally struggle germinating celery seeds no matter what, so I always overstart and have poor germination no matter the age of the seeds. Sowing extra seeds ensures the best chance of having the number of plants I need to feed my family.
Kohlrabi Seeds
Kohlrabi seeds start slowly declining in germination rate after year one but seem to drop more rapidly after year three. My current kohlrabi seeds are about five years old now and are germinating around 60%.
Pea Seeds
Pea seeds, with their thick skins like bean seeds, also should be replaced after three years. I buy pea seeds in bulk and sow my oldest seeds first, followed by the newer seeds. There’s a noticeable yet slight germination decline when the seeds are older than three years.
Spinach Seeds
Last year, I started an entire tray of spinach seeds (72 seeds) and had three germinate. My seeds were five years old. I bought some new seeds and had nearly a 100% germination rate using the same seed starting methods. I support the recommendation of replacing spinach seeds after year three.
Replace After Four Years
Beet Seeds
Beet seeds, which I would also include turnips and rutabagas in this category, should be traded out for fresh seeds after four years. My beet seeds are currently over five years old since I bought a bulk bag in 2020. While the germination rate is a little lower, it’s still around 70% for my favorite Detroit dark red beets. That’s not poor enough for me to replace at the moment.
Brussels Sprouts Seeds
I’ve grown brussels sprouts in my garden every year but have always tried new varieties to find the best option for my space. While the recommendation is to replace after four years, I have no personal experience with older seed packets of brussels sprouts.
Cabbage Seeds
Cabbage seeds truly can last up to five years with minimal decline in germination rates. I can attest to this. My go-to large cabbage variety was bought in 2019 and is still going strong. Though this year I’m down to my last few seeds and will be replacing.
Cauliflower Seeds
Cauliflower seeds are a similar type of seed to cabbage and brussels sprouts and can also last up to four years. I haven’t tried germinating older cauliflower seeds since I’m still looking for my favorite variety.
Eggplant Seeds
With proper storage conditions, eggplant seeds can last and produce viable plants for up to five years. I don’t plant many eggplants each season and often sow old seeds. My four-year-old seeds last season germinated over the 60% mark so I opted to keep them for another year.
Kale Seeds
Kale seeds are another hardy seed type. I have an exorbitant number of seeds saved from my favorite kale plants that went to seed in 2018. They still germinate well over 50%.
Melon Seeds
Watermelon, cantaloupe, honeydew, and other melon seeds are in the same family as cucumber and squash seeds. With their thicker skins, they can be counted on for at least four years. Sometimes longer.
Pumpkin Seeds
Pumpkin seeds are another substantial and hardy variety that stays viable for a long time. Aim to replace them after year four for best results.
Radish Seeds
Another member of the brassica family, along with kale and beets, radish seeds can last a long time, up to four years with minimal impact to germination rates.
Squash Seeds
Similar in shape and size to pumpkin seeds, squash seeds remain viable up to four years. With the right care, one packet of your favorite summer or winter squash can last for seasons to come.
Swiss Chard Seeds
Swiss chard seeds, which look like spinach and beet seeds, last up to four years. I’ve had the same packet of bulk bright lights swiss chard seeds for more than five years now, and their germination rate has only dropped slightly.
Tomato Seeds
Tomato seeds, including tomatillos and ground cherries, are a hardy crew that last four to five years. Stories abound of gardeners finding air-tight containers of saved tomato seeds decades old and germinating them successfully.
Replace After Five Years
Cucumber Seeds
More substantial than many seeds, cucumber seed can easily grow after upwards of five years of storage. I tend to burn through all of my cucumber seeds before I get to that date, but I’ve had one variety from 2017 that’s still going strong.
Should You Throw Away Your Seeds On Their Expiration Date?
Absolutely not. Seeds can germinate whether they’re a year old or 50 years old. The rate of success, or the germination rate, is what changes. So if you have a packet of 100 seeds that’s newer, you may see a 98% germination rate. If you have a five-year-old packet of seeds, depending on the type, you could see a 75% germination rate. A ten-year-old packet of seeds could drop down to a 25% germination rate. So with a packet of 100 older seeds, you could still get 25 healthy plants. You don’t know until you try.
I love the story of Luke from the YouTube channel MI Gardener. He successfully germinated and grew a Giant Crimson Tomato, a variety thought to be extinct, from seed packets 80+ years old. Two seeds germinated and one plant survived. He produced cuttings, saved seeds, and now sells the seed variety in his store.
Can You Plant Expired Seeds?
Yes, you can plant expired seeds as the expiration date doesn’t tell you whether or not you have viable seeds. It’s a sell-by date and can help you, the gardener, determine how old the seeds are. If they’ve been stored properly and are free of mold or mildew, plant away!
An easy way to tell if the seeds you have are viable is to do a simple germination test. Take ten seeds from the packet, place them on a moist paper towel, fold the towel over the seeds, and place in a plastic bag. Put the bag in a warm spot and check in about a week to see if the seeds have sprouted. This test will give you an idea of the basic viability of your seeds, but also a super basic idea of the germination rate to expect.
So plant those expired seeds and grow something beautiful and delicious in your garden this season.
