Does Grass Seeds Go Bad?

Sherin Woods is a California-based DIY enthusiast and garden design aficionado. With a background in Environmental Science, she combines creativity and sustainability in all her projects. A Pinterest favorite, Sherin is committed to eco-friendly solutions and has contributed to various home and garden publications. Her areas of expertise include DIY project planning, sustainable garden design, and content creation.
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Are you confused about the grass seeds, its storage, and viability? Find out about Does Grass Seeds go Bad and the factors that affect them!

Does Grass Seeds Go Bad

Many gardeners store large quantities of grass seed in the shed or garage, to reseed any bare spot in the lawn. But what about their expiry date? Let’s find out does grass seeds go bad or remain workable for a long time to come!

Check out our article on growing ornamental grass here! 

Do Grass Seeds Expire?

Grass seeds are sold with an expiry date stamped on the bag and can go bad with time. Hence it’s a good idea to throw away unused seeds that have crossed the expiry date.

The seeds lose the germination ability with time, and you need to use more seeds than required. Also, you need to spend more time in irrigation, feeding, and nurturing expired seeds that are also not going to produce grass anymore.

How Long can Grass Seed be Stored?

According to many grass seed selling companies and horticultural professionals, any type of packaged plant seeds faces a reduction in their germination rate of about 10 percent per year.

If the package or box of the grass seed states that 90 percent of the seed would germinate when fresh, it will decline to 80 percent in year two, and 10 percent each year subsequently though it is also affected by how you are storing the seeds.

It has been mentioned in a study conducted by Oregon State University, that 50 percent of perennial ryegrass, Kentucky bluegrass, and fescue seeds can germinate after 3-5 years if stored properly, while 50 percent of creeping grass seeds can sprout after five years or more.

How to Store Grass Seeds?

Keep grass seeds in a cool, dry place, with proper air circulation. The temperature needs to remain between 40-50 F (4-10 C). Do not store seeds in a garage or shed where temperature can go below 32 F (0 C). Also, keep the bags off the floor where mice can’t reach them.

Keep the seeds in a cellar or basement, as long as it is dry and cool. You can also refrigerate them as well. However, don’t forget to place an open box of baking soda or a commercial desiccant. It helps in soaking up the excess moisture.

How to Check Seed’s Viability?

Does Grass Seeds Go Bad 2

Spread a damp paper towel on a plane surface. Now, place 10-12 seeds in a row and roll the sheet. Put it in a zipped plastic bag, and keep it in a warm place for one week.

After that, remove the bag and count how many seeds germinated. If 6-8 seeds sprout, it means they have a 60-80 percent germination rate. In case 4 or fewer seeds germinate, then the rate is 50 percent or lower, and you need to acquire fresh grass seeds.

Factors Affecting Seed Viability

The viability of seeds depends on storage conditions. Seeds can remain viable for a more extended period if appropriately stored in a cool and dry place. The factors that affect seed viability are:

  • Seed moisture content: The necessary internal moisture content is 10-20 percent for most seeds. When exposed to moisture below this level or high humidity, they have a chance of dying. Generally, seeds do not go below their optimal internal moisture levels. The surrounding humid conditions influence them and they absorb extra moisture from the atmosphere.
  • Temperature: For the majority of seeds, the correct storage temperature is above freezing but below 60 F (15 C). Temperature above 100 F (37 C) can affect seed’s viability severely.
  • Humidity: If you are storing seeds in open containers or cloth sacks, then there is a chance of change in the moisture content of seeds.


Use old grass seeds for reseeding or top seeding, but do not expect a high germination rate as compared to the fresh turfgrass seeds. Store new grass seeds in a tightly sealed plastic bag or container, so they cannot soak moisture. This increases the viability of seeds. Also, keep the seeds away from hot shed or garage and store them in a cool and dry place, indoors.

If the storage temperature is cold, and relative humidity (RH) is dry, then seeds will be viable for long. Refrigerate them, in airtight containers, or keep at the coolest location in your home. If you store the seeds as per the instructions on the label, then they’ll stay viable for up to five years!

Here are 12 DIY seed starting hacks you should have a look at! 

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