Does Grass Seed Go Bad? How to Preserve It

If you’ve bought old grass seeds in the past year or months and are wondering whether you can still use them effectively after long, the short answer is that it depends.

Improper storage and other factors can affect the viability of the seeds long before the ravages of time eat into them.

Here’s what you should know to help understand grass seeds and their inevitable expiry.

What Makes Grass Seeds Go Bad?

Here are some questions to ask to understand where and how your seeds can go bad:

1. How Long Has It Spent in the Bag?

Before sowing the seeds in your lawn, you should check the bag, especially if you purchased it in bulk and stored it for several months. 

It all depends on the storage. Most cool-season grass seeds (like Kentucky bluegrass and fescue) remain viable for 2-3 years under ideal conditions, while warm-season grass seeds (like Bermuda, Zoysia) typically maintain good viability for 1-2 years if properly sealed. Once it’s opened, other factors begin to affect how well it preserves.

Using your grass seeds within a year of opening them can be beneficial. Anything more can affect the viability of grass seed, leading to poor or no germination.

2. What Is the Quality of the Seeds Themselves?

Long before the bag of grass seeds finds its way into your home, various conditions affect the seed quality. Factors like harvesting conditions, production location, and storage environment can all affect the germination rate.

When purchasing grass seeds from the store, mark each with a “tested” date and germination rate. This date can indicate how fresh the seeds are, ensuring that the bag of seeds you got isn’t old.

For germination rate, the ideal percentage should be at least 80%. Provided you use the grass seeds within a year of purchasing them, you can expect the germination rate to be within the desired range.

Seed viability decline rate per year varies significantly by grass species and seed storage conditions. Kentucky bluegrass might lose 20-25% viability in the first year under suboptimal conditions, while perennial ryegrass might only lose 5-8% when properly stored.

3. Are the Seeds Coated?

Sometimes, grass seeds come coated to help absorb moisture and increase seed longevity. Depending on the brand of product you get, some manufacturers add insecticides, fungicides, or fertilizers to the coating. This coating can help preserve your seeds for longer when stored in optimal conditions. 

While some coatings contain fungicides that can affect soil microorganisms, many modern seed coatings are designed to work with beneficial fungi. Coated seeds offer significant benefits including better germination in challenging conditions, moisture retention, and protection against diseases.

4. What Container Has It Been Stored In?

A significant factor affecting how long your seeds can keep while maintaining maximum viability is where they’ve been stored. The best way to store grass seeds is in the manufacturer’s bag they came with.

You can also use buckets with screw-top lids that help keep out moisture and pests. If you’re not planting right away, you can store the seeds in bulk storage bags in a cool, dry place. Make sure the container is airtight, and check the seeds for mold and excess moisture whenever you’re ready to use them again. 

What Are the Signs of Bad Grass Seeds?

Seeds gone bad don’t have to first fail the germination test before they can be declared bad. Here are some obvious signs to look out for:

1. Seed Discoloration

Visually inspecting the grass seeds is a quick way to tell whether the small, dart-shaped structures have altered physical appearance. As a rule, bad seeds will look less vibrant and display uneven coloring. 

There’s usually some dull, faded, or splotchy cast with most spoiled seeds. Other seeds look darker than usual, while others may feel damp with fungus or mold visible on them.

2 Musty Smells

Sniffing the seeds is another quick way to tell whether they have gone bad. Healthy seeds smell fresh, while bad seeds smell musty or rotten.

When stored improperly in damp spaces, temperature conditions can foster the growth of bacteria, which causes it to smell bad.

3. Brittle Feel

After the eye and nose test, it’s time for the touch test. Scoop out a handful of the seeds and feel them in your palm carefully for inconsistencies in texture.

Some might have gone soft, breaking easily the moment you apply pressure. Other times, you’ll find that some become brittle or mushy. Such discoveries indicate that your seeds have gone bad.

Good seeds should feel dense, smooth, and slightly hard when pressed together. They shouldn’t release powdery residue or feel brittle, rough, or cracked, despite being dry

4. Weight

It’s also important to check the weight of the seed when it’s been in store for a while. Fresh seeds should feel substantial, not lightweight or hollow 

Viable seeds contain a live embryo and starchy endosperm, which makes them dense. When the seeds go bad from decay, they noticeably feel hollow or shrivelled from weight loss.

5. Sell-by Date

If your grass seeds were store-bought, you can check the sell-by date to understand the germination rate better. The sell-by date is the last recommended date retailers should sell the product while it’s still at its best quality. 

Note, however, that the sell-by date isn’t necessarily an expiry date, so you can still use your grass seeds beyond this timeline. A slightly reduced germination rate may mean you’ll have to overseed your lawn when you sow next. 

How to Keep Grass Seeds From Spoiling

To help store your grass seed packs and make sure the grass seed is still viable months later, follow these steps:

• Keep it dry: Moisture is the biggest enemy of grass seeds, as it causes the growth of bacteria and mold. Ensure that your seeds are always stored in cool, dry places.
• Make sure the container is airtight: An airtight container prevents both moisture and pests from reaching your seeds. Sealing the bag prevents this, helping the seeds keep their viability for longer. 
• Date and label the containers: Penning and noting timestamps can be useful to know when a product has exceeded its shelf life and when it’s best to use it.
• Store correctly: If your place of storage can get excessively hot, move it somewhere cooler. Proper storage helps preserve the seeds from damage by heat.
• Avoid sunlight: Prolonged exposure to sunlight and UV radiation weakens the outer seed coats and makes them more vulnerable to disease. 
• Keep off the floor: Ground moisture can cause the seeds to clump together and decay. Place other material or a platform between the container and the ground to keep it fresher for longer.

Testing Your Unused Grass Seeds

If you’ve inspected to check for spoiled grass seeds and still are unsure about the condition of the stored seeds, you can subject them to a germination test.

To do this:

• Scoop out a few seeds
• Place them on a slightly damp paper towel
• Roll everything up and keep it in a plastic bag
• Place the plastic bag in a warm place for five to seven days
• After the duration, check the seeds to see how many have sprouted to know how viable the seeds are. 

During the test, maintain consistent moisture and specific temperature ranges (65-75°F for cool-season grasses, 75-85°F for warm-season varieties) to make sure the test results are accurate.

A Healthy Lawn Begins With Healthy Grass Seeds

A crucial step towards achieving a healthy lawn is sowing viable seeds whose germination rates have not been negatively impacted.

The passage of time, storage conditions, and the type of seeds can determine how well your seeds will thrive when they’re finally sown. 

At SunCoLawns, we thrive on selecting the best grass seeds for your lawn and can help you get the best value possible, whether you’re new to landscaping or not.

Let us be your guide towards achieving your dream lawn! Contact us today!

FAQs

Does Freezing Spoil Grass Seeds?

Freezing is NOT recommended for most homeowner grass seed storage. Residential freezers undergo temperature fluctuations during defrost cycles, which can damage seeds through moisture condensation. Commercial seed storage uses specialized freezers with controlled humidity. For homeowners, cool, dry storage (around 40-50°F with low humidity) is preferable to freezing.  

What Can You Do if Your Grass Seeds Have Gone Bad?

If your grass seeds exhibit any traces of spoil, getting them trashed isn’t always the only option. If you’re overseeding your lawn for the new season, you can add it to the mix. 

Can Grass Seed Expire?

Although grass seeds don’t have expiry dates like other products, they still expire and lose their viability over time. The duration of this process can change due to various factors, such as storage, opening, and general preservation.

How Long Can Grass Seeds Keep Before Going Bad?

The shelf life of grass seeds depends on their storage conditions, seed type, and whether they’re coated or uncoated. The germination rate reduces by about 10% each year, so ensure that you use the seeds well before this period.