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Grass Seed Not Growing After 3 Weeks – What To Do

We have heard stories throughout the years of homeowners having trouble with their grass seed not germinating as expected or grass seeds not germinating at all. If you join these gardeners, you may want to know why the newly seeded areas on your existing lawn show no sign of growth.

Many factors can affect grass germination rather than it being merely the grass seed you have. For example, you can have some of the best Jonathan Green grass seed and still find a lack of germination in your grass seeds.

In our guide, you can learn more about what to do if grass seed doesn’t grow. By the end, you’ll have more information on how to get a great lawn because you know how to get seeds to germinate at the best possible rate. (Read Why Did Stihl Discontinue The Ms290)


What Is New Grass Seed Germination?

To start to grow is where the seed germinates and can vary between grass types. Ryegrass can germinate in 7 days and grow to 3 inches in three weeks.

If Kentucky bluegrass and fescues make up most of the mixture, a 10% ryegrass mixture will not germinate quickly as Kentucky Bluegrass is the slowest species. When picking grass seed, you need to check product labels to ensure the species of grass included can germinate quickly or slowly.

Once you know this, you’ll know when to expect germination according to the type of grass seed you spread.

Here are more main reason grass seed won’t germinate as you expect.

1. Soil Temperatures

After raking the lawn and noticing bare spots, many homeowners apply grass seed throughout the spring months. But even in the same place, spring weather can change soil temperatures beside the air temperature after a frost, for example.

In the spring, chilly, wet weather is primarily to blame for grass seed’s slow germination as soil temperatures are low and the ground is overly wet. When grass seed is sown in the soil below 50°F, it frequently won’t grow.

In reality, you need 7–10 days with air temperatures over 60°F for the soil temperatures to reach 50°F and provide these warm soil conditions. So, you can find grass germinating more readily in August than in April.

If you have a small area and wonder, will grass seed germinate on top of soil? You would be fortunate if it did. It can get blown by the wind and eaten by birds without protection. Ensure your soil temperature is inside the range for 2–3 days before seeding for newly planted grass seed growth.

  • Warm-season grasses: Bermuda, Zoysia, and Centipede soil temperature of 65–70 are best for the seed.
  • Cool-season grasses: Rye, Fescue, and Kentucky Bluegrass need a soil temperature of 50–65 (10–18).

2. Water

Although water is essential for seeds to germinate, too much water can hinder germination and lead to poor grass seed growth. Excessive moisture will drown the young grass seeds, causing them to float to the surface rather than take root in the soil. (Read What Temperature Is Too Cold To Water Grass)

For this reason, excessive spring rains can delay germination. Moist soil helps seeds sprout, while dry makes seeds remain dormant. So, it is important to spread your grass seed on the moist ground and then water consistently.

  • Water before seeding, so the soil is moist to 6–8 inches.
  • Water for 5 minutes after spreading and covering your seeds.
  • Water 5–10 minutes twice daily after seeding to keep the soil moist to 1–2 inches.

3. Sunlight

lawn on a sunny day

All grass seed need some sunshine to produce chlorophyll and promote photosynthesis to grow. You can have more shady areas than sunny ones when the tree canopy increases come spring, thus blocking sunlight from your grass plants.

You can have problems growing grass in your shady region if it just gets 1-2 hours of sunlight each day. Your chances of success significantly rise if this same area receives 3–4 hours of sunlight each day, whether it is filtered.

Low soil pH in frequently shaded areas makes it great for tree growth but not grass seed. Besides your grass seed mixtures not getting the sun, you can also find soil temperatures colder in heavily shaded areas.

4. Soil pH

Do you know your soil’s pH? If the soil pH is too alkaline or acidic, you’ll have trouble growing grass seed. In soil with a pH of 5.8 to 7.2, grass grows best. Before purchasing grass seed and fertilizer, test the soil in places where you have difficulty growing grass seed.

Hardware and garden stores provide homeowner test kits, and you can either use a self-test kit or mail a sample to your county cooperative extension office for analysis.

Correcting the pH of the soil can significantly enhance the results of planting if you’ve had problems with grass seed development. Healthy soil enables grass to grow and discourages weeds. Apply the amount of lime or other soil amendments after conducting a thorough test.

5. Fertilizers

Before the new seed can grow, your lawn may require a boost if it hasn’t been fertilized in a while. The grass, however, could be harmed if you apply too much fertilizer to your lawn.

When growing grass from seed, the proper soil nutrients are crucial. New grass needs fuel, yet after sowing, it could be time to fertilize and add soil foods if you don’t notice healthy growth.

Using a slow-release fertilizer with a high nitrogen content encourages grass growth. To promote the development of young roots, you should include phosphorus in any soil foods you use as part of your lawn care. (Read Mixing Bermuda Grass With St Augustine Guide)

6. Weed Controls

You’ll find specific weed controls must not be used before, during, or immediately following seeding to allow grass seed to grow. After spraying, new grass seed cannot grow for 3–4 months because of pre-emergent crabgrass preventers.

However, they keep grassy weeds and crabgrass at bay without injuring seedlings. After any broadleaf weed controls have been applied to the lawn, you cannot plant grass seed for 3–4 weeks.

Only after the seed germinates and the grass has been cut three to four times should you use broadleaf or grassy weed control products. Pre-emergent weed killers eliminate seeds as they begin to grow. Follow these two guidelines for pre-emergent weed killers and grass seed to avoid damaging your grass.

Spreading grass seed should be delayed for eight weeks after using a pre-emergent weed killer. Pre-emergent weed killer should not be used for six weeks following seeding.

7. Cover Grass Seed

Plant grass seed 1/4–1/2 inch deep. Any deeper grass won’t grow and break the surface. Grass seeds that are not adequately covered will not sprout. Birds and other animals consume uncovered grass seed, which can be blown away.

Ensure seed-to-soil contact by brushing a thin layer of soil over your grass seed and using a lawn roller to compact the soil on the seeds.

Walk on new grass seed after four weeks as new grass shoots can be killed by walking on them. In addition, using a lawn or outside space can slow grass seed growth, so make it off-limits till the grass matures.

With too many activities, before or after seeding, you could have compacted soil. So, you’ll need to aerate your soil, so the roots can access air and water can penetrate and drain. 

What To Do If Grass Seed Doesn’t Grow?

lawn grass

Yes, you may end up buying grass seed in the wrong amount and use too much or too little grass seed when planting a new lawn. Too much seed might lead to unneeded competition for nutrients, light, and water.

Your seed should still generally germinate, but it might not grow well. When seeding a new lawn, I like to use a lot of seed (around 1.5 times the manufacturer’s recommended), but it’s crucial not to overdo it, or you risk stunting the growth of your entire new lawn.

It’s also possible that you used too little seed, of course. If this is the case, you could notice that your lawn has some thin or spotty sections. It’s crucial to measure your lawn correctly since using too much or too little grass seed may lead to problems. The same holds for other items, like fertilizer and pre-emergent.

The primary determinant of your seeding success or failure, but seed quality comes closely behind, is your work to prepare the place and care for your seed until and in the weeks following germination.

In most countries where it is appropriate to use cool-season grasses, early fall is the best season to plant grass (such as Fescue grass and Kentucky Bluegrass).

Generally, it’s best to stay away from sowing grass seed in the spring because your young seedlings will have to contend with perennial weed pressure and summer’s hard heat and drought.

The best time of year to seed warm season grasses (such as St. Augustine Grass) is late spring, except for southerners, since this will allow them to establish themselves during their prime growing season. (Read Grass Clippings Over Grass Seed Guide)

Time for Germination Of Grass Seed Differs

Remember that the germination period varies depending on the variety of grass seed. This implies that the time it takes for each type of grass to grow differs. Despite its notoriously slow germination rate, Kentucky bluegrass is worth the wait.

Kentucky bluegrass is one kind that grows slowly yet is best for lawns. The germination of Kentucky bluegrass seed might take up to one month. If you’re thinking, “Why is my grass seed not growing? “… It can simply be a seed that takes longer to sprout and show growth.

It might also take between 14 and 21 days for tall fescue and creeping grasses. Wide varieties of self-repairing rhizome grass take a little longer to sprout.

If Perennial Ryegrass is appropriate for your environment and demands, and you’re seeking a grass species that germinates particularly quickly, give it some thought. It will frequently germinate in about 5-7 days.

Water the Correct Amount

You must provide your grass seed with the right amount of water if you want it to grow successfully. Watering your grass seed at the wrong time or using too much or too little water will quickly lead to issues.

An excessive amount of water may thoroughly wash the seeds away or interfere with their germination ability. Because of this, trying to plant grass seed in the spring during a period of heavy rain can produce disappointing results. The seeds may be drowned by too much water.

They will float to the surface, be plucked from the soil, or wash to low areas of your yard (or worse, down the storm drain). Water your freshly seeded lawn frequently enough to keep it moist but not frequently enough to risk drowning it.

The period of grass growth before the appearance of sprouts is the most crucial. During that time, pay extra attention to how you’re watering.

Using A Mix Of Grass Seeds

Many homeowners also use a mixed seed that contains seeds for many grass species. Each will have a unique growth trajectory. Some seeds, such as ryegrass, may sprout fast, while others, such as Kentucky blue, may take many more weeks to germinate and establish.

Don’t be alarmed if you use a mix of grass seed and your lawn appears sparse when grass seedlings first appear. This is most likely what you are experiencing, and you will have proper germination.

If you decide to sow a seed combination rather than a single species, you can expect that the seeds will differ, especially in the early days. Once all of your new grass has grown in, that is typical and ideal for a lawn.

Various types of grass that grow in different ways can improve the appearance of your lawn all year long.

Because of environmental factors, you’ll have a more consistent lawn overall if one grass variety thrives when another does not work in a particular area of your lawn.

Grass Seed Not Growing After 3 Weeks