How Long Does Grass Seed Last in an Open Bag? Find Out Here

Whether you’re storing grass seed in bulk or forgot about a bag you got a couple of years ago, you’re not alone. Many people prefer grass seed over sod because it’s much more natural and affordable. However, leaving the bag open can invite mold and bacterial growth.

Grass seed lasts two to three years in an open bag if your roll it up and seal it as much as possible. If the bag is open to the elements, there’s a high chance it’ll get covered in moisture and mold. Expired grass seed can be used, but it’s usually only about 10% as effective as it should be.

In this post, we’ll cover everything you should know about using grass seed from an open bag. We’ll also talk about how long it lasts if the bag is closed, what you can do with expired grass seeds, and more.

Tip: If your grass seed is bad and you don’t want to risk the 10% ineffectiveness issue mentioned above, there’s plenty of high-quality grass seed on Amazon to choose from. Make sure you seal the bag with a clip after opening it, though!

Does Grass Seed Go Bad in the Bag?

Grass seed can go bad in the bag from becoming stale, humid, or too dry. The seeds will eventually crack or get moldy, so it’s important to rotate the bags and use them within a few years of purchasing them. The good news is that many grass seeds can last well beyond the predicted expiration date.

It’s also important to keep in mind that, just because it’s not growing in your yard, doesn’t mean the whole bag is bad. There are plenty of factors that could prevent your grass seeds from sprouting, including the weather, temperature, humidity, foot traffic, root growth space, and more.

For example, if there are too many pine needles piling up in the yard, there won’t be enough room for sunshine, water, and nutrients to get to the soil. Find out how to vacuum your pine needles here.

Note: If you think your grass seed is bad because it’s not growing in your yard, make sure you’ve chosen the right grass for the season. There are dozens of warm-weather and cold-weather grasses that don’t grow well in certain environments. Knowing which grass you’re planting is crucial to its success!

If you’re unsure whether or not you can still use the grass seed in an opened or unopened bag, try the quick test in the next subheading.

How Do You Know if Grass Seed Is Still Good?

To know if grass seed is still good, you can place the seeds in a cup of water and test if they float. If they rise to the top after a few minutes, they’re likely not good. Those that sink are still in good shape and will likely germinate. This test is free and easy, so why not give it a try?

Here’s the detailed process as provided by Horticulture Mag:

1. Place a few grass seeds in one cup of room temperature water.
2. Wait 15 minutes to give the seeds some time to soak up the moisture.
3. Floating seeds won’t germinate, but those that sank will still sprout.

If there are several seeds that sink and more that float, the bag is mostly expired. That being said, you can still use expired grass seeds. We’ll cover more details about what you can do with the seeds that won’t germinate later in the article. For now, you can try this test to figure out what condition the opened seeds are in.

If you have a closed bag of grass seed, it’ll last much longer than you might think. Read on to learn how durable sealed grass seed bags can be.

How Long Does It Last in a Closed Bag?

According to SF Gate, an unopened bag of grass seed can last three or more years. Some brands claim to last up to five years, which could provide quite a reliable supply of grass seed for the incoming years. Grass seeds can last longer if they’re kept in a cool, dry space without too much sunshine, rain, humidity, and debris.

So, how can you make your grass seed last longer in the bag?

• Keep it in a shed, garage, or other enclosed space. Wind, rain, and sunlight can ruin the seeds, so it’s important to protect the bag so it doesn’t rip open or fall apart.
• Mix the seeds in the bag (if it’s opened) to aerate them, shift the weight, and prevent moisture from pooling at the bottom of the bag.
• Use the seeds annually to keep them fresh and grow your lawn to a thick, vibrant green color. Overseeding has plenty of benefits, especially if your lawn is patchy or the seeds are expired.
• Store opened grass seed bags in an airtight container to preserve them for a long time.

Grass seeds can stay in good condition for many years, but improper storage can make them expire in less than a year. Following the tips mentioned above is a surefire way to get the most out of your fresh grass seeds, whether or not the bag is opened.

Will Grass Seed Grow if You Just Throw It on the Ground?

Grass seed will grow if you just throw it on the ground, but it has to sink into the soil, have enough water, and receive enough sunlight. These necessities are highly unlikely without your input, especially since lawns are unnatural.

In the wild grass naturally spreads and plants itself, but it takes a long time. If you want your grass seeds to germinate, you have to hydrate the soil, rake the seeds, and ensure they get enough fertilizer and sunlight to grow healthily.

If you want to have a grassy lawn without the world, you could get artificial turf or sod. These options are ideal if you prefer to reduce the germinating process, but they both have drawbacks.

You can’t walk on the sod for a while after it’s planted since the roots have to grow. On the other hand, sod isn’t natural, it can overheat, and there are many debates about whether or not it’s bad for the environment.

What Should You Do With Expired Grass Seeds?

If you have expired grass seed, you can plant it or toss it into a compost bin. Expired grass seed still contains a few essential components for fertilizer once it breaks down. It’s unlikely to germinate, but it works for patchy areas and overseeding since most of them won’t grow.

The best way to dispose of expired grass seed is to throw it into the yard waste bin. It decomposes, so there’s no point in throwing it into the dumpster or recycling bin. Squirrels, raccoons, and many other animals eat grass seeds, too.

Keep in mind that it’s best to try the aforementioned test with a cup of water to know if your grass seeds are in good condition before throwing them away. However, if you notice mold or fungus on the seeds, don’t use them! They can spread to the whole lawn and cause long-lasting issues.

In Conclusion

Just because you accidentally left the grass seed bag open for a couple of months doesn’t mean it’s expired. Do your best to seal the bag and prevent it from getting moldy, humid, or dirty. You can use the expired seeds, but remember that they’re much less effective and likely won’t germinate at the same rate as brand-new, unopened grass seed bags.