Dethatch or Aerate First? Proper Order Explained 

To maintain a healthy lawn, you need to water the lawn, fertilize it, and mow it.  However, even with this regular maintenance, the grass may start to thin and display other signs of nutrient deficiency and under-watering. 

When the lawn displays the above symptoms, the roots are not getting sufficient nutrients and water. To rectify the problem, you need to dethatch and aerate the lawn.

Should I Dethatch or Aerate First?

Whether to dethatch or aerate will depend on the problem facing your lawn. However, if you have to do both, it is advisable to dethatch and then aerate the lawn. Check the best time to aerate and overseed a lawn.

Dethatching and aeration will help the roots of your lawn access air, water, and nutrients effectively. Although the end goal is similar, the two lawn practices are different because they remedy different problems.

Below are the key differences between dethatching and aerating.

  1. Dethatching is simply removing thatch from the lawn, while aeration is poking holes to relieve soil compaction.
  2. Dethatching is done using a dethatcher, while aeration uses a lawn aerator.
  3. Dethatching is done before over-seeding, while aeration can be done before or after over-seeding.

When Should I Dethatch?

Dethatching involves removing thatch (layers of living and dead grass shoots, stems, and roots that build up between the grass blades and the roots).

The right amount of thatch benefits the lawn because it keeps the grass warmer in winter and shades the soil from the sun, helping it retain moisture. The thatch also breaks down into nutrients that feed the grass.

However, when the thatch exceeds ½ an inch, it is no longer beneficial to the lawn as it will prevent water, oxygen, and nutrients from reaching the grass roots, causing stunt growth. The thatch also becomes a breeding ground for insects and fungal disease-causing microorganisms.

Below are the causes of excessive thatch on the lawn.

  • Water lightly and frequently.
  • Using too many herbicides and fertilizers kills the microbes that help in the breakdown of organic matter.
  • Overfeeding grass with nitrogen causing it to grow aggressively.

Signs that your lawn needs dethatching include;

  1. The lawn is spongy and springy.
  2. The grass is thinning or drying.
  3. When the lawn grass starts losing its color.
  4. If the lawn is affected by fungal diseases and insects.
  5. If new shoots are struggling to emerge. They will also appear weak.

After observing the above signs, you can do a thatch test to ascertain before you dethatch. Dig a 3 inches hole and remove a slice of soil. If the thatch is more than ½ an inch, you need to dethatch.

Importance of dethatching

  1. Enables the grassroots to get water, air, and nutrients.
  2. Encourages new root growth.
  3. Fertilizer is able to reach the soil. 
  4. Improved drainage.
  5. It helps grass seeds germinate appropriately if done before overseeding.

When Should I Aerate?

Aeration involves correcting soil compaction by loosening the soil. It is done by poking holes and removing sections of the soil. 

When the soil is compacted, the soil becomes very hard such that air, water, and nutrients cannot get to the roots. The grass will be stressed and will grow slowly or not grow at all. It can also start to dry out. It will also be vulnerable to diseases and insects.

Below are some causes of soil compaction.

  • High foot traffic on the lawn.
  • Operating machinery on wet soil, e.g., vehicles or using a lawn mower when the soil is wet.

Although it is important to aerate and dethatch, it is only done when necessary because if done often, you will destroy the lawn. Below are signs that indicate you need to aerate the lawn.

  1. The soil is hard and difficult to pierce with a shovel.
  2. The emergence of weeds that thrive in compacted soil.
  3. If no weeds are growing on bare patches, and you have not used any weed killer.
  4. The grass starts to thin.
  5. Slow or no growth of lawn grass.
  6. The lawn fails to drain properly after watering or rainfall.
  7. The emergence of lawn diseases such as the brown patch.

After observing the above aeration signs, you should do an aeration test to ensure it is the cause because the signs could also indicate other lawn problems like grubs

Dig out a section of the grass (at least 6 inches deep). Measure the length of the root. If the root’s growth is only 1 and 2 inches deep, you need to aerate.

Importance of aerating 

  1. Improves root growth and the overall health of the lawn.
  2. Enables nutrients to reach the roots effectively. 
  3. Helps curb soil erosion.
  4. Increases microbes’ presence in the soil. 
  5. Increases drought tolerance of the lawn.

Can you dethatch and aerate at the same time?

If your lawn has both thatch and soil compaction problems, you can dethatch and aerate at the same time. There are lawn machines that have both a dethatcher and aerator that will ease your work if you want to perform the two at the same time. 

However, if you cannot access the machine, you can dethatch and aerate afterward. If the lawn thatch problem is not extreme, aeration can help sort the thatch and soil compaction. When you aerate, microorganisms that help decompose thatch will show up. 

How often should you aerate or dethatch your Lawn?

It is important to dethatch and aerate during the grass growing season to enable the grass to recover quickly. Dethatching when the grass is dormant could kill the grass because it might not recover from the injuries sustained from dethatching.

For cool-season grasses such as Kentucky bluegrass and tall fescue, aeration and dethatching should be done during early spring or early fall. For the warm season, grasses dethatch and aerate during late spring or early summer. 

How often you aerate a lawn will depend on the type of soil and the traffic on the lawn. A sandy soil lawn should be aerated once in two years, while a clay soil lawn should be aerated once or twice a year.

A high-traffic lawn should be aerated twice a year. Fast-growing grasses such as Kentucky bluegrass should be dethatched at least twice a year. 


Dethatching and aeration are important practices to grow a healthy lawn. Dethatching helps in removing thatch while aeration corrects soil compaction. 

Dethatching should be done before aeration, but if there is no thatch problem, you can aerate the lawn instead. Aeration should be done once a year, but for lawns with high traffic, you can aerate twice a year.


  1. University of Maryland Extension: Lawn Aeration
  2. University of Illinois Extension: Lawn Aeration and Overseeding
  3. University of Missouri Extension: Managing Thatch in Home Lawns

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