How To Plant Grass Seed On Existing Lawn [ Full Guide ]

Planting grass seed on an existing lawn can be a great way to fill in sparse areas, improve the overall health and appearance of your lawn, and introduce new grass varieties. However, there are several crucial steps to take in order to ensure successful germination and growth. Before you begin this process, it’s essential to assess the condition of your existing lawn, choose the right grass seed, and carefully prepare the area for seeding. By following these steps and maintaining proper care after planting, you can establish a lush, healthy lawn that enhances your outdoor space.

Quick Answer: How To Plant Grass Seed On Existing Lawn

Planting grass seed on an existing lawn involves several key steps:

  1. Assess the condition of the existing lawn, identifying sparse areas, soil quality, and existing grass type.
  2. Choose the right grass seed for your specific climate, soil type, and lawn use.
  3. Prepare the existing lawn by mowing, dethatching, and aerating to create an optimal seedbed.
  4. Spread grass seed evenly over the prepared lawn and lightly rake to ensure good soil contact.
  5. Water the newly seeded lawn regularly and provide proper care to support successful germination and growth.

Assessing The Condition Of Your Existing Lawn

Before planting grass seed on your existing lawn, it’s important to evaluate the current condition of your turf. This assessment will help you identify areas that need improvement, understand the existing grass type, and determine the overall health of your lawn.

Identifying Problematic Areas

Walk around your lawn and take note of any sparse or thin areas where the grass is not growing well. These areas could be caused by factors such as heavy foot traffic, inadequate sunlight, poor soil quality, or existing grass types that are not well-suited to your region.

Assessing Soil Quality

Take a soil sample from different areas of your lawn to assess its quality and composition. You can use a soil testing kit or send the samples to a local agricultural extension service for analysis. The results will provide valuable information about the pH levels, nutrient content, and overall health of your soil.

Identifying Existing Grass Types

Identify the types of grass that are currently growing in your lawn. This information is essential when selecting new grass seed, as you’ll want to choose varieties that complement or match the existing grass to maintain a uniform and cohesive look.

Understanding Sunlight And Shade

Observe the sunlight and shade patterns in your lawn throughout the day. Note areas that receive full sun, partial shade, or full shade, as this will influence your choice of grass seed varieties.

Choosing The Right Grass Seed

Selecting the right grass seed is crucial for the success of your lawn renovation project. Consider factors such as climate, soil type, maintenance requirements, and the intended use of your lawn.

Climate Considerations

Choose grass seed varieties that are well-suited to your local climate. Some grasses thrive in cool, northern regions, while others are better adapted to the heat and humidity of the south. Selecting grass seed that matches your climate zone will ensure better overall performance and resilience.

Soil Type Compatibility

Consider the soil type in your lawn when choosing grass seed. Some grass varieties thrive in sandy soil, while others prefer loamy or clay-based soil. Select grass seed that is compatible with your soil type to encourage healthy growth and establishment.

Lawn Use And Maintenance

Consider how you use your lawn and the level of maintenance you’re willing to commit to. For example, if you have pets or children who frequently play on the lawn, choose grass varieties that are resilient and can withstand heavy foot traffic. Additionally, consider the mowing height and frequency that different grass types require, as this will impact the maintenance demands of your lawn.

Mixing Grass Seed Varieties

In some cases, it may be beneficial to mix different grass seed varieties to create a more resilient and visually appealing lawn. For example, blending cool-season and warm-season grasses can ensure year-round greenery, while combining shade-tolerant and sun-loving varieties can address different light conditions in your lawn.

Preparing The Existing Lawn For Seeding

Properly preparing your existing lawn for grass seed ensures that the seeds have optimal conditions for germination and establishment. This process may include mowing, dethatching, aerating, and amending the soil as needed.

Mowing The Lawn

Before seeding, mow the existing lawn at a height that allows the grass seed to make good soil contact. Trim the grass to a height of around 2 inches to expose the soil without scalping the lawn excessively.


If your lawn has a significant thatch buildup, consider dethatching before seeding. Thatch is a layer of dead grass, roots, and organic matter that accumulates on the soil surface. Excessive thatch can impede seed-to-soil contact and hinder proper germination. Use a dethatching rake, power rake, or vertical mower to remove thatch and create a more favorable seedbed.


Aerating the lawn is essential for improving soil structure, promoting better water and nutrient penetration, and enhancing seed-to-soil contact. Use a core aerator to remove plugs of soil from the lawn, allowing air, water, and nutrients to reach the grassroots more effectively. Aeration also helps alleviate compaction, which can hinder seed germination and root development.

Soil Amendments

Based on the results of your soil test, consider adding soil amendments such as lime, sulfur, or organic matter to correct pH imbalances, improve nutrient levels, and enhance soil structure. Incorporating these amendments can create a more favorable environment for new grass seed to take root and thrive.

Overseeding Or Spot-Seeding

In addition to preparing the entire lawn for seeding, you may need to focus on overseeding or spot-seeding specific areas that require improvement. Overseeding involves spreading grass seed over the entire lawn to thicken existing grass and fill in sparse areas, while spot-seeding targets specific patches or bare spots that need attention.

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Seeding The Lawn

Once the existing lawn is adequately prepared, it’s time to spread the grass seed evenly and effectively. Proper seeding techniques are crucial for achieving uniform coverage and successful germination.

Selecting Quality Seed

Purchase high-quality grass seed from a reputable supplier or garden center. Look for seed blends or mixtures that contain certified seed varieties with high germination rates and purity levels.

Calculating Seed Application Rates

Determine the appropriate amount of grass seed to apply to your lawn based on the recommended seeding rates for the specific grass varieties you’ve chosen. Application rates may vary depending on factors such as overseeding vs. establishing a new lawn and the seed size.

Spreading The Seed

Use a broadcast spreader or a handheld spreader to distribute the grass seed evenly over the prepared lawn. Start by walking the perimeter of the lawn to create a border, then work back and forth in a crisscross pattern to ensure thorough coverage. Pay close attention to avoid overlaps and gaps to achieve uniform distribution.

Raking The Seed

After spreading the grass seed, lightly rake the soil surface to ensure good seed-to-soil contact. Raking also helps bury the seeds at the optimal depth for germination without burying them too deeply. Avoid excessive raking, as this can disrupt seed placement and lead to uneven germination.


After seeding, water the entire lawn thoroughly to initiate the germination process. Use a gentle spray or mist setting on a hose or irrigation system to prevent disturbing the seeds. Keep the soil consistently moist but not waterlogged to support germination and early growth.

Caring For Newly Seeded Lawn

Once the grass seed has been sown, diligent care is essential to promote successful germination and establishment. Proper watering, mowing, and protection from external stressors will contribute to the healthy growth of your new grass.

Watering Schedule

Maintain a regular watering schedule to keep the soil consistently moist in the seeded areas. Avoid allowing the soil to dry out, as this can hinder germination. Be cautious not to overwater, as waterlogged soil can lead to seed rot and other issues. Monitor moisture levels and adjust watering frequency based on weather conditions and soil moisture.

Mowing New Grass

Refrain from mowing the newly seeded lawn until the grass has reached a height of at least 3 inches. When mowing, use a sharp blade and set the mower at a higher cutting height to avoid stressing the young grass. Bagging the clippings initially can also help prevent smothering of the delicate seedlings.

Protection From Traffic And Pests

Minimize foot traffic and other stressors on newly seeded areas to prevent damage and disturbance to the emerging grass. In addition, be vigilant against pests, such as birds or small animals, that may be attracted to the freshly seeded lawn. Consider using protective netting or scare tactics to deter these potential threats.

Fertilization And Maintenance

As the new grass begins to establish, consider applying a starter fertilizer to provide essential nutrients for growth. It’s important to follow recommended fertilization practices for newly seeded lawns to avoid causing stress or burning the young grass. Additionally, continue regular maintenance practices, such as removing fallen leaves and debris, to support the healthy development of the newly seeded areas.

Planting grass seed on an existing lawn requires careful planning, preparation, and maintenance to achieve successful results. By assessing the condition of your existing lawn, selecting the right grass seed, and properly preparing the area for seeding, you can lay the foundation for vibrant, healthy grass to thrive. With diligent care and attention to watering, mowing, and protection during the germination and establishment phases, you can transform sparse or worn-out areas of your lawn into lush, resilient greenery. Following these steps will ultimately lead to a rejuvenated and visually appealing lawn that enhances your outdoor living space for years to come.

Clearing Debris And Weeds

Planting grass seed on an existing lawn is a great way to rejuvenate your yard and fill in any bare or patchy areas. Whether you want to improve the appearance of your lawn or repair damage caused by foot traffic, pets, or harsh weather conditions, planting grass seed can help you achieve a healthy and vibrant lawn.

Before you begin planting grass seed, it is essential to clear your existing lawn of any debris and weeds. This will create a clean, nutrient-rich environment for the new grass seed to thrive. Follow these steps to effectively clear debris and weeds from your lawn:

  1. Start by removing any large debris, such as fallen branches or rocks, by hand or with a rake. Dispose of this debris properly.

  2. Use a weed trimmer or mower to cut the existing grass short. Set the cutting height to approximately 2 inches to ensure you don’t scalp the lawn.

  3. Inspect your lawn for weeds and unwanted plant growth. Remove any weeds manually, ensuring you remove the entire root system to prevent regrowth. For larger areas affected by weeds, consider using a broadleaf weed killer according to the instructions provided by the manufacturer. Allow sufficient time for the weed killer to take effect before proceeding.

  4. Rake the lawn thoroughly to remove dead grass, thatch, and any other remaining debris. This will help ensure good seed-to-soil contact, allowing the new grass seed to establish itself easily.

Aerating The Soil

Aerating the soil is a critical step in preparing your existing lawn for grass seed. Aerating involves creating small holes in the soil to promote better air circulation, water absorption, and root development. Follow these steps to aerate your lawn effectively:

  1. Rent or purchase a core aerator. This machine removes small plugs or cores of soil from the lawn, creating the necessary channels for air, water, and nutrients to reach the roots.

  2. Before aerating, thoroughly water your lawn to ensure the soil is moist but not overly saturated. This will make it easier for the aerator to penetrate the soil.

  3. Start aerating by making parallel passes across your lawn, overlapping each pass by half to ensure complete coverage. The aerator should penetrate the soil to a depth of 2-3 inches.

  4. After aerating, leave the soil cores on the lawn. Over time, they will break down and contribute beneficial organic matter back into the soil.

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Fertilizing The Existing Lawn

Fertilizing your existing lawn will provide the necessary nutrients for both your existing grass and the newly planted grass seed. Follow these steps to fertilize your lawn:

  1. Test your soil to determine its nutrient needs. This can be done through a soil test kit available at garden centers or by sending a soil sample to a reputable testing facility. The results will help you choose the appropriate fertilizer and application rates.

  2. Choose a high-quality grass fertilizer with a formulation that suits your soil’s needs. Look for a fertilizer with a balanced ratio of nitrogen (N), phosphorus (P), and potassium (K), such as a 10-10-10 or 16-4-8 blend.

  3. Apply the fertilizer evenly across your lawn, using a broadcast spreader for large areas or a handheld spreader for smaller sections. Follow the instructions provided by the manufacturer regarding the appropriate application rate.

  4. Water your lawn thoroughly after fertilizing. This will help the fertilizer penetrate the soil and reach the grassroots.

  5. Repeat the fertilization process as recommended by the fertilizer manufacturer or based on the specific requirements of your grass variety.

Seeding Techniques And Methods

Now that your existing lawn is prepped and fertilized, it’s time to plant the grass seed. Follow these techniques and methods for successful seeding:

1. Choose The Right Seed

Selecting the right grass seed for your existing lawn is crucial for achieving the desired results. Consider factors such as climate, soil type, sun exposure, and intended use of your lawn. Consult with a local garden center or lawn care professional to determine the best grass seed variety for your specific needs.

2. Prepare The Seedbed

To create an optimal seedbed, follow these steps:

  • Rake the soil to ensure it is smooth and free of any large clumps or stones.
  • Fill in any low spots with topsoil to level the seedbed.
  • Lightly compact the soil using a lawn roller or by gently walking over the area.

3. Apply The Seed

There are two common methods for applying grass seed: broadcast spreading and overseeding.

A. Broadcast Spreading

  • Use a handheld broadcast spreader or a walk-behind spreader.
  • Fill the spreader with the appropriate amount of grass seed, following the recommended seeding rate provided by the seed manufacturer.
  • Begin spreading the seed by walking in straight paths, making sure to overlap slightly to ensure even coverage.
  • After the initial passes, change directions and repeat the process to ensure complete coverage.

B. Overseeding

  • Overseeding is the process of spreading grass seed over an existing lawn to fill in bare or thin areas.
  • Use a handheld broadcast spreader or a walk-behind spreader.
  • Reduce the recommended seeding rate by half to avoid excessive seed application.
  • Begin spreading the seed, focusing on the areas that require additional coverage.
  • Rake the seeded areas lightly to ensure good seed-to-soil contact, which is crucial for successful germination.

4. Watering And Maintenance

After seeding, proper watering and maintenance are vital for the success of your new grass seed.

  • Water the seeded areas immediately and continue to keep the soil consistently moist. Light, frequent watering is recommended to prevent the soil from drying out.
  • Avoid overwatering, as excessive moisture can lead to disease and fungal issues.
  • Monitor the seeded areas regularly and adjust your watering schedule based on weather conditions and the seed’s germination progress.
  • Keep foot traffic to a minimum on newly seeded areas to avoid damaging the delicate seedlings.
  • Apply a light layer of straw or mulch to help retain moisture and protect the seed from birds.

Planting grass seed on an existing lawn requires thorough preparation, including clearing debris, aerating the soil, and fertilizing the existing lawn. The seeding process involves selecting the right seed, preparing the seedbed, and applying the seed using either broadcast spreading or overseeding methods. Watering and proper maintenance are crucial for the success of the newly planted grass seed. By following these steps, you can achieve a lush and healthy lawn that enhances the beauty of your home.

Spreading The Grass Seed

If you have a lawn that has some bare patches or areas where the grass isn’t growing as well as it should, it may be time to plant some new grass seed. Planting grass seed on an existing lawn can be a little tricky, but with the right techniques and a little patience, you can have a lush, green lawn in no time.

Before you can plant grass seed on an existing lawn, you need to prepare the soil. Start by raking the area where you want to plant the grass seed. This will remove any dead grass, leaves or debris from the surface of the soil and help to loosen the soil, making it easier for the new grass seed to take root.

Once you have cleared the area, you can spread the grass seed. The best way to spread grass seed on an existing lawn is to use a broadcast spreader. A broadcast spreader will help you to distribute the seed more evenly and will ensure that you don’t miss any spots.

When selecting the grass seed, consider the climate, soil condition, and the amount of sunlight the area receives. It is also important to check the label of the grass seed to make sure that it is suitable for overseeding on an existing lawn.

Once you have the grass seed, pour it into the spreader and adjust the settings according to the instructions provided by the manufacturer. Walk behind the spreader, and move in an up and down or side to side motion, depending on the spreader model, to ensure that the seed is evenly distributed across the entire area.

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Watering The Newly Seeded Lawn

After spreading the grass seed, it is important to water the newly seeded lawn immediately. This will help to settle the seed into the soil and promote germination. Water the area gently, so you don’t disturb the seed. You can use a garden hose or a sprinkler for this.

In the first few weeks after planting, it is important to keep the soil consistently moist. Water the area every day or every other day, depending on the weather. If it is hot and dry, you may need to water more frequently. Avoid overwatering, as this can lead to fungus and other problems.

Maintaining The Newly Seeded Lawn

Once the grass has started to grow, it is important to take care of the area properly to ensure that the new grass seedlings establish themselves. Here are some tips on maintaining the newly seeded lawn:


Wait until the grass has reached a height of about 3 inches before mowing. When you do mow, set the mower blade to the highest setting and only remove the top third of the grass blades. This will promote healthy growth and help to protect the newly seeded lawn.


After the grass has been growing for a few weeks, you can fertilize it with a high-quality lawn fertilizer. This will help to promote strong, healthy growth and give your new lawn the nutrients it needs to thrive. It is important to follow the manufacturer’s instructions when fertilizing.


Weeds can be a problem for a newly seeded lawn because they can easily outcompete the new grass seedlings for nutrients, water and sunlight. To prevent weed growth, you can use an herbicide, but make sure it’s suitable for use on newly seeded grass. Alternatively, you can hand-pull them as soon as they appear.


It’s important to continue watering the newly seeded lawn until it becomes established. After the first few weeks, reduce the frequency of watering but make sure to maintain a consistent moisture level in the soil.

Avoid Heavy Traffic

Try to avoid walking on or allowing heavy traffic on the new grass. The seedlings are still fragile, and heavy traffic can damage or kill them.

Troubleshooting Common Issues

Sometimes even with the best care, a newly seeded lawn can face some common issues. Here are a few problems and how to address them:

Patchy Growth

If you notice patchy growth, or some areas of your newly seeded lawn don’t seem to be growing well, you may need to reseed those areas. Follow the preparation and seeding steps described earlier in this article.

Fungal Disease

Fungal disease can be another problem. You’ll know if you have a fungal disease if you see a white or gray film on the grass blades. To treat this problem, you may need to apply a fungicide to the lawn.

Insect Infestations

Insects, such as grubs, can also attack new grass seedlings. Look for signs of insect activity, such as holes in the soil or chewed grass blades. If you suspect you have an insect infestation, you may need to apply an insecticide to the lawn.


Planting grass seed on an existing lawn can be a great way to get your lawn looking lush and green again. However, it does require some patience and care to ensure that the new grass seedlings establish themselves properly. By following the tips described in this article, you can have a beautiful, healthy lawn in no time.


What Is The Best Time Of Year To Plant Grass Seed On An Existing Lawn?

The ideal time to plant grass seed on an existing lawn is during the early fall or spring when soil temperatures are between 60-70 degrees Fahrenheit. This allows for optimal seed germination and root development.

Do I Need To Prepare The Existing Lawn Before Planting Grass Seed?

Yes, preparing the existing lawn is crucial for successful seed growth. This includes mowing the existing grass to a shorter length, raking or dethatching to remove any debris and dead grass, and aerating the soil to loosen it up for better seed-to-soil contact.

How Much Grass Seed Should I Use On An Existing Lawn?

The recommended amount of grass seed for an existing lawn is 1-2 pounds per 1000 square feet. However, this can vary depending on the type of grass and the condition of the existing lawn. Consult the seed bag or speak to a professional for more specific recommendations.

Can I Mix Different Types Of Grass Seed When Planting On An Existing Lawn?

Yes, you can mix different types of grass seed when planting on an existing lawn. This can help create a more diverse and resilient lawn. However, make sure to choose grass seeds that have similar growth and maintenance requirements to ensure they grow evenly.

How Often Should I Water The New Grass Seed On My Existing Lawn?

Watering is critical for the success of new grass seed growth. Keep the soil consistently moist, but not soaking wet, by watering lightly 2-3 times a day for the first 2-3 weeks. After that, gradually reduce watering to once a day for the next 2-3 weeks, and then water as needed depending on the weather and soil moisture.