When & Why to Aerate and Overseed Your Lawn

Aeration and overseeding are important if you want to maintain a healthy, lush lawn. However, you’re probably wondering when the best time to aerate and overseed is. Today we are sharing tips to tell whether or not you should aerate and overseed, plus the best time of year to guarantee you end up with great results.

Why Aerate and Overseed Your Lawn

Aerating and overseeding your lawn can be an important part of your lawn care maintenance schedule.  

What is Aeration?

Aeration is the process in which you mechanically (use a machine or implement) to penetrate and puncture holes within your lawn. Mechanical aeration with a gas-powered aeration machine or core aerator is the standard for this practice. 

Liquid aeration is another method that is commonly mentioned, but it fails to meet the criteria to actually change or allow increased circulation to the soil.

During this aeration, a plug of soil is removed and discarded onto the lawn. 

Depending on your goals, these plugs that are created can be either removed or left alone on the surface. 

Aerating relieves soil compaction within your soil’s surface to allow for better movement of water, air and nutrients which can lead to a healthier lawn.

Aeration also creates a good seedbed if you are overseeding your lawn. 

When these plugs or cores are removed, the holes that are created make a great seedbed to ensure good seed-to-soil contact, which is one of the most important aspects of successful seeding.

What is Overseeding?

Overseeding is the process in which you add new seeds to an existing lawn. 

There are a few different scenarios in which you might want to consider overseeding. A major consideration is the type of grass you have.

If you have a cool season lawn which is primarily tall fescue or ryegrass, you may develop dead or patchy areas during the growing season.

Overseeding is also a great way to add new or improved varieties of grass to your lawn. 

Newer cultivars tend to be more drought tolerant These cool-season grasses do not have stolons or rhizomes, so they lack the ability to regenerate and spread. The best way to get these grasses looking their best is to overseed. 

Overseeding cool-season grasses is best accomplished in the early fall. 

Warm-season grasses traditionally do not require overseeding as their growth is aggressive in nature as these grasses have the ability to spread when they are cared for properly.

A common practice in southern states is to overseed your warm season grass, usually bermuda, during the winter as it will turn dormant and brown with the cooler temperatures. Bermuda is most commonly overseeded with ryegrass during this time of year to retain a green lawn.  

Aeration and overseeding, especially in cool season lawns, go hand in hand. If you have an existing area of turf that is in need of seeding, aeration plus overseeding is one of the most common ways to ensure you have a successful outcome and a green lush lawn for the season to come.  

When is the best time of year to aerate and overseed your lawn for optimal results?

The best time to aerate and overseed your lawn is in the fall. 

Fall weather and warmer soil temperatures provide the perfect opportunity to perform these tasks. It’s important to time these events at least 45 days before your first frost date.  

Fall aeration and overseeding is optimal but can also be performed in the spring if necessary. 

If your aeration and overseed is planned for spring you need to do so after your winter’s last frost and before warmer summer temperatures arrive. 

While early spring seeding can be done but note that your new grass will have a weaker root structure going into summer compared to grass that was planted the previous fall.

How can you tell if your lawn needs aerating or overseeding?

Aeration is needed when the lawn becomes hard and compacted. 

Indications of compaction include grass plants that have a shallow root structure. A yard that becomes hydrophobic where water pools easily and is unable to disperse into the soil. Your lawn may also benefit from aeration if you notice areas where the grass is thin and it has trouble establishing.

Aeration is also a great method to use when you are amending your soil to improve its structure and performance. For example, it’s common to amend clay soil or improve water penetration by aerating, collecting the plugs (cores), and then adding a different medium like sand.

Cool season lawns primarily made up of tall fescue and ryegrass can benefit from overseeding almost annually.

These bunch-type grasses are great and quick to establish but do not have the ability to fill in if areas are damaged or dead. 

The best method to rejuvenate a tall fescue or ryegrass lawn is to overseed. 

Common cool season mixes will include tall fescue, ryegrass, and Kentucky bluegrass and can also benefit from overseeding. 

Please note: If your lawn is 100 percent Kentucky bluegrass, overseeding is not necessary, as it has the ability to spread and fill in. If your Kentucky bluegrass lawn has some larger bare spots, you can easily spot-seed those areas.

Warm-season grasses do not need to be overseeded as they have the ability to spread aggressively on their own with proper nutrient feeding. Warm-season lawns can benefit from aeration, which is best performed after it greens up and breaks winter dormancy or in the fall if you are going to overseed a winter grass like rye 

What are some of the benefits of aerating and overseeding your lawn regularly?

If you have a cool season bunch type grass, like tall fescue, ryegrass or a mix, you can benefit from aeration and overseeding when the lawn is thin or patchy.

Annual aeration and overseeding will help keep your lawn full and improve weed control in thin turf areas or bare patches of soil.

Aeration alone is also a great tool if you have compacted soil and can be performed annually, usually in the fall or spring. 

Aeration will relative compaction and allow water and nutrients to flow easily through your soil. This process will help with root system development and promote strong deep roots, increasing drought tolerance and ultimately improving your grass’s health. ‘

Can I Overseed and Aerate My Lawn Myself?

Aerating and overseeding is a task that many homeowners are able to accomplish on their own. 

Core aeration machines can be rented at your local home improvement store or tool rental center. These machines tend to be heavy and there is definitely a learning curve for operation.  

Beyond renting a proper aerator, there are some manual aeration tools available that can also be purchased at your local home center. 

These tools usually have two or three tines (the implement that will create a plug and can be an option for small lawns. 

Manually aerating your lawn is a doable task, but it is extremely time-consuming as you would want to aerate in two or three directions.  

For seeding, you would also need to purchase or have access to a drop or rotary spreader. Spreading seed is similar in task to spreading fertilizer on your lawn, so if you can perform that task, you can easily spread seed and overseed your lawn. 

Should I Hire a Lawn Aeration Service?

To have a professional aerate and overseed your lawn, the cost will depend on the size of the lawn and the type and quality of the seed that is used. 

For a 5,000 sq ft lawn expect to spend somewhere between $150 and $300. Location is another thing to consider, as pricing will vary depending on the cost of living in your area.

Professionals with the proper equipment can successfully aerate and overseed your average homeowner’s lawn in a couple of hours.  

If you don’t own the equipment or have the time to aerate your lawn yourself, hiring a lawn care professionals to do it for you might be a good option.