Grass seeds are designed to last long. But they can lose their viability due to physiological factors and storage conditions. Temperatures and moisture are the main storage factors that can affect seed longevity.
How about if you have leftover seeds from last season? Is it good to throw them or store them for the next planting season? Saving the grass seed for next year is a good idea since buying new ones is expensive. All you need is to store them in the right conditions.
However, grass seed is likely to lose its viability with time. In this case, you need to learn how to test grass seed viability to avoid wasting your time and labor and maintenance cost. A viability test will help you know if the seed is worth sowing. Also, you will be able to figure out how many seeds to sow.
How to Test Grass Seed Viability
1. The paper towel test
The purpose of the paper towel test is to determine how well the seed will perform in the yard. If the seeds are about 50% viable, you may consider planting extra seeds to get a beautiful and uniform lawn. But if the seeds are not viable, it is good not to bother planting them.
Here are 7 steps for performing the paper towel test
- Gather equipment
Germination test involves materials such as:
- A paper towel
- A zip-seal plastic bag
- About ten seeds
- Place the seeds into a damp paper towel and fold it. Be careful not to mix grass seed varieties since different seeds have various germination rates.
- Seal the paper towel and the seeds in a plastic bag. Label the bag with the grass seed variety and the date you placed them.
- Place the sealed bag of grass seeds in a warm spot.
- Check the seeds after a few days to see whether there is any change. Depending on the grass seed type, the viable seeds can sprout in a few days, while others can take several weeks.
- After the seeds sprout, count those that can be seen above the ground. Multiply the number of seedlings by 10 to determine the germination rate.
- If none of the seeds germinated, then the seeds are not good for sowing. But if half of the seeds sprout, you will need to plant thickly since they may not have much success.
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2. Water test
The water test is an easy and fast way to determine grass seed viability.
Here is how to determine grass seed viability using water
Place about 10 grass seeds into a container full of water and leave them for about 15 minutes. If they sink, then they are still viable. But if they float on water, chances are, they will not germinate.
However, this method is not as accurate as the paper towel test. It will only give you a general idea. In this case, it is good to compare the two grass seed viability tests to see how closely they are.
Also read: Can I store grass seed in garage over winter
3. Soil test
The soil test works similarly to the paper towel method. This procedure is essential for those grass seeds that only perform well in the soil. For instance, if you want to plant tall fescue grass, you can consider clay soil.
- Spread soil in a tray or a container
- Wet the soil and plant the seeds
- Spread another layer of soil on top of the seeds and spray some water
- Keep the soil moist and warm until the seeds germinate
- Determine the results of the grass seed germination rate
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FAQs On Testing Grass Seed Viability
How do you know if grass seed is still good?
So, you have noticed bare spots on your lawn. You decide to use the old grass you kept in the store or garage a few months ago. How will you know if the grass is still good? Like other natural products, grass seed has a shelf life. While you can look at the expiry date to determine seed viability, storage factors such as moisture and temperature can affect the seed’s longevity.
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Nevertheless, even the expired grass seeds can result in a healthy lawn. But to be on the safer side, it is good to check the germination success by conducting a seed viability test. You can use the paper towel or the soil test for reliable results.
What makes some grass seeds fail to germinate in the viability test?
Seeds germinate in suitable conditions. But if grass seeds are dominant or dead, they may not germinate. Seeds can die due to excessive heat or high humidity.
However, some seeds remain hard and firm during the viability test. This may be due to dormancy. So, how can you treat the grass seed to overcome the dormancy?
You can use methods such as:
Stratification: Stratification involves placing the grass seed in a cold environment for some time.
Scarification: This involves breaking the seed coat with a knife or abrading it with a file.
Leaching: This method involves washing and soaking the grass seeds with fresh water for 12-48 hours.
When is the grass seed regarded as viable?
Many varieties of grass seeds can last for at least 3-5 years. And after this duration of time, only around 20-30% may germinate. As you know, storing the grass seed is not easy. The temperatures may fluctuate, making the seed lose its viability.
Also, there might be an increase in the humidity levels, which can increase the risk of molds. This situation makes many properties owners wonder if their grass seed is viable or not.
Grass seed is considered viable when it can germinate under the right conditions. On the other hand, grass seed is non-viable when it fails to germinate under suitable conditions such as the right temperature, moisture, and the treatment for dormancy removal.
No one would like to plant grass seeds only to find out that they did not germinate or only a few sprout. That’s why learning how to test grass seed viability is essential.
A seed viability test will help you know the number of seeds alive after storage. This technique is essential when planting. If the grass seeds have greater viability, you will require fewer seeds to establish a lush and healthy lawn.