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Does Grass Seed Go Bad? – Tips on Storage and Germination Check

If some seeds are only viable for 3 to 4 years, does grass seed go bad as well? Every spring, gardeners are excited to bring back the lush green lawn in their yards. Some of us even buy lawn seeds in bulk, with the excess usually stored in the garage until spring. 

Nothing can be sadder for a gardener than expired seeds and gardening materials. In this post, we will share the longevity of grass seeds and the preservation techniques used by farmers.

We will also share the factors that affect the seed viability so you won’t mourn your expired and rotten ones. 

Table Of Contents

Q: Does Grass Seed Go Bad or Expire?

Yes, grass seeds go bad or expire, but there’s more to them than that. Two factors can indicate that grass seed is still alive or viable. These include the seed germination rate, seed age, and the moisture in the grass seed. 

The germination rate is usually on the label of the grass seed you bought. It determines the probability of the grass seeds developing into a seedling.

The range is usually around 80% to 90% germination rate for the first year. However, the germination rate of grass seeds usually declines by 20% to 10% annually.

If you’ve been into gardening for a while, you probably know that you’ll need to apply more seeds to compensate for their low germination rate. If you use a 3-year-old grass seed from your garage, you’ll need to place more seeds to grow your desired amount of grass. 

Viability and Germination Rate

According to Johnny Seeds, a seed company, the seed age determines their germination rate and viability.

Seed viability refers to their ability to provide quality seedlings. Viability of a seed declines before its germination rate. So, your long-stored grass seeds may germinate but produce weak and low-quality seedlings. 

How To Know If Your Grass Seeds Are No Longer Viable?

If you are not a fan of labeling your seeds, chances are you lost track of the expiration date or when you bought them.

Some brands of grass seeds may also provide an expiry date or use until info on their labels. A simple test to know the viability of the grass seeds that you have at hand is by germinating a few amounts in a sandwich bag. Here’s how:

Germination test
Germination test


  • Tissue paper
  • Ziplock bag
  • Spray bottle with water
  • 10 pieces of grass seeds from storage


  1. Place the grass seeds in tissue paper. Fold it to cover the grass seeds.
  2. Spray water on the tissue paper to add moisture to the seeds.
  3. Put the damp tissue paper inside the sandwich bag and place it at the desired germination temperature of the seed variety. Check the label to know if it is warm-season grass or cool-season grass. 
  4. Check how many seeds have successfully germinated. If five seeds have sprouted, your grass seeds have around a 50% germination rate. Therefore, the number of seedlings will be half of the grass seeds you plant. The quality of the seedlings may also be affected due to the age of the grass seed. 

Do Expired Seeds Still Grow?

The label of your grass seed may say that it is expired, but it may still germinate. The only problem is it will no longer provide the quality of the grass seedlings you are looking for. In some cases, the majority of the seeds will also no longer germinate.

5 Factors That Affect The Lifespan of Grass Seeds in Storage

Aside from the age of grass seeds, the quality of the storage environment can also affect its condition.

Here are the factors that you need to consider when storing your grass seeds to preserve their viability for a long time. 


Grass seeds need a cool, dry, and dark place to maintain viability. However, the type or variety of grass seed also plays a role in getting the right temperature to maintain its viability.

The ideal storage temperature of most grass seed varieties is 42°F. It usually has the same temperature produced by refrigerators. 

Freezing temperatures may prolong the life of your food but not the live seeds. Extreme heat or cold can bake the grass seeds, reducing their viability.

Most novice gardeners place their seeds in the garage. Though it is cold in the garage during fall or winter, the temperature is not well-maintained, which can still affect the viability of the grass seeds.

Fluctuations in the temperature in the garage or shed can also cause condensation inside the packaging of the grass seeds that will cause moisture. 


The reason seeds are dried before storage is to reduce the seed moisture. In essence, moisture brings back the grass seeds to life. So, it is ideal for grass seeds to have lower moisture levels to maintain their viability. 

If the seed moisture is high, their storage life declines. Moisture also attracts fungus to get to your seeds and form molds and mildew, even mushrooms. When that happens, your grass seeds are already dead and no longer ideal for planting.


Sunlight is another factor that can cause premature germination on seeds. The light activates certain enzymes in the seeds, which jumpstart their growth. Storing your seeds in areas where they receive light can reduce their germination and viability rate. 


Humidity is the amount of moisture in the air. If your grass seeds have been exposed to a humid environment, it may cause organisms to grow and affect the overall moisture level in the grass seed. Grass seeds with increased moisture are more likely to acquire mold and fail to germinate. 

Pest Infestation

Aside from environmental risks, place your grass seeds in a location where pests like rats can’t reach them.

Usually, grass seeds come in a big plastic bag prone to accumulating moisture in humid environments and not sturdy enough to be rat-proof.

How To Store Your Grass Seeds And Extend Their Shelf Life?

According to Oregon State University, the best way to avoid risks associated with storing grass seeds or any seed type is to avoid storing them.

That’s why some commercial seed companies already find several consumers for their grass seeds long before the harvest day to ensure they are planted immediately. 

However, if you want to save the spare grass seeds that you have, here are some ways to store them safely:

Storage Container

The container for your grass seeds should promote good airflow. You may place the seeds in any of the following containers:

Burlap sack: A burlap sack is an ideal option to store grass seeds since it is breathable. It can prevent moisture buildup. You can place these sacks in a cool, dry place. However, you have to ensure that the storage location is free from rodents. Rodents can chew off the burlap fabric and feast on your grass seeds.

Grass seeds in burlap sacks
Grass seeds in burlap sacks

Glass jar with an airtight lid: Another best storage recommendation for grass seeds is a rodent-proof glass jar. To prevent moisture buildup due to condensation, you need to place desiccant inside the jar. You may put the seed jar inside the refrigerator until spring.

Seed jars
Seed jars

As you transfer the seeds in the jar, make sure to cut out the brand, testing date, and expiry date from the packaging and label it in the seed jar. The label will serve as a reminder of how long you can use the seeds.

Storage box: If your spare grass seeds are too many for a jar to handle, you can place them in a storage box like the one you use in moving in or storing your gadgets in your garage.

Storage box
Storage box

You may place a desiccant or an open box of baking soda to control the moisture and make the seeds last in a condition until spring.

Storage Location

Now that you have secured the moisture-proof containers for the grass seeds, their location is the next thing you need to consider.

Here are some locations that have a constant temperature that ranges around 40°F and 50°F degrees for storing seeds:

  • Heated garage: During the winter season, leaving your grass seeds in a shed or unheated garage can affect their viability. If your HVAC system is connected to your garage, you can safely leave the seeds along with your gardening tools. Just make sure that you place it in a container with a desiccant to prevent the moisture from building up. 
  • Refrigerator: Your fridge is another good location that can maintain a cool and dry environment for your grass seeds is in your fridge. Maintain its temperature at around 40F to maintain its quality. 
  • Basement or wine cellar: Your basement is usually the best place to hide your seeds that can lead them undisturbed. However, placing them in the basement can also make you forget the grass seeds you stored. Make sure to post a note or a visual reminder around your house about your grass seeds. 
  • Closet: The lack of a basement or storage space should not discourage you from storing seeds. You can place the seeds at the back end of your wardrobe. It is a perfect location to keep them away from moisture and sunlight. Just make sure that it is out of reach of children.

Frequently Asked Questions (FAQs)

Is it okay to use old grass seed?

It’s okay to use old grass seed. However, do not expect a high germination rate and produce good seedlings.

If the grass seeds are from your stock from the last spring, their germination rate may reduce by 10%. So, you may need to add more grass seeds than the recommended application rate.

Can grass seed go bad in the bag?

Yes, but it will take 3 to 5 years before it can expire compared to an opened bag of grass seed. As long as they are stored in a cool, dry, and dark place, you can slow down the decrease of their viability.

Does grass seed expire when frozen?

Yes. Grass seeds are baked in extreme temperatures. They should only be placed in above freezing temperatures that range from around 40F to 50F.

What to do with old grass seed?

You may check its germination rate by sprouting ten seeds in a zip-lock plastic. If the seeds germinated, you may still use them to cover the patches in your lawn in spring. Otherwise, if the grass seeds are no longer viable, you can add them to your compost pile.

How long does grass seed take to sprout?

Grass seeds usually take about 5 to 10 days to germinate. However, the duration depends on the variety of grass and the germination environment.

If the germination requirement of the grass variety is met, you can expect them to sprout within five days. Also, if you are using an old seed with a reduced germination rate, you must add more seeds to ensure you’ll achieve your desired coverage.

Can I store grass seed in the garage?

No, the extreme temperatures in the garage during winter can affect the viability of your grass seed. It may also encourage moisture buildup that can speed up the reduction in the viability of the grass seeds.

However, if your garage is connected to your HVAC, then you can store it in the garage. You may place a desiccant in their container to ensure a moisture-free environment.

Final Thoughts

We hope that this post helped you learn more about taking care of your seeds and proper storage techniques. Seeds can last for a long time as long as the standard seed processing and storage is observed. 

The timer of the seed variability starts as soon as they are removed from the mother plant. Proper seed processing and storage make some seeds stand out from the rest and are usually sold in the market at a higher cost. All in all, regardless of the quality, it’s still best to only buy seeds based on what you need to reduce waste. 

If you have a secret seed storage technique for your grass seeds, we highly encourage you to share it with our community. Comment your technique below to help more farmers save and enjoy lush green lawns.

Also, please don’t forget to share this post with your friends so that they’ll know how to handle their old grass seeds stored in their garage or storage room.

About Jeanne Keith F.

Jeanne Felipe is a content creator of anything that can make this world a better place. She is a self-improvement junkie and a nature lover at heart. She loves to help people through her writing, either finding the right tools or doing the right thing to accomplish their goals. Quotes, sprouting plants, and cute dogs make her feel ecstatic. In her free time, she loves tending her garden and cooking Chinese and Mexican dishes. Connect her on Linkedin.

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