A healthy, well-draining lawn will feel solid and even when it is stepped on.
When your lawn retains too much moisture, it will begin to have a spongy, soft, sometimes squishy texture.
So what causes this excess water retention and makes your lawn spongy?
A spongy lawn occurs when a thick layer of decaying organic material, known as thatch traps moisture on top of the soil. As a result, the grassroots are shallow because they are unable to penetrate deep into the ground. Your lawn will have a soft, squishy feel under your feet as you walk on it.
With proper lawn care and maintenance to remove the thatch layer and fix any possible drainage issues, you will be able to have a beautiful lawn once again.
It is usually not difficult to repair a soggy lawn, but it may take some time to find and completely solve the primary cause.
Keep reading to learn more about why your lawn is spongy and the steps you need to take to fix it.
Table of Contents
How Does Thatch Build Up?
Thatch is a layer of decomposing plant materials consisting of roots, stems, dried leaves, and other organic matter.
This layer of decaying organic materials builds up in a layer between the grass and the soil.
It is normal to have a layer of thatch on your lawn, but when it becomes thicker than 3/4″ of an inch, you will need to remove it.
Mowing your grass too short or cutting too much grass at one time after letting your lawn grow too long will cause thatch to develop.
Both of these actions will result in excess of dead plant material.
The microbes and insects in your lawn will not be able to break down the extra organic matter quickly enough, and it will build up in a thick layer on your lawn.
Thatch will form in any lawn, but it occurs more frequently in grounds with higher clay content in the soil.
It is also easier for thatch to form in lawns with shallow grassroots, which is often caused by fertilizing too often.
Lightly watering your lawn too frequently instead of deeply watering for a more extended period will also cause your grass to have a weak and shallow root system.
As the thatch layer gets thicker, the grassroots have a more difficult time growing down into the soil.
What Does a Thick Layer of Thatch Do to Your Lawn?
Mowing your grass while it is wet will increase the chance of your grass clippings becoming clumped together and forming a layer of thatch.
Every time you mow your lawn, the decomposing grass clippings are added to the thatch layer.
As the thatch layer builds up on your lawn over time, it will trap more moisture and nutrients on top of the soil instead of allowing them to soak down into the roots of your grass.
This will not only cause nutrient deficiencies, but it will also make your turf more susceptible to rot, erosion, disease, and fungal infections.
Your grass will not receive the proper nutrition to stay healthy, and it will become fragile.
Fertilizers will not affect your lawn because the nutrients will never reach the grassroots.
When enough moisture builds up in the thatch layer, your yard will begin to have a squishy, spongy texture.
As your grass dies, you will have more muddy areas and bare spots from soil erosion.
What Causes Your Lawn To Retain Too Much Moisture?
Several reasons for your lawn to retain too much moisture, and most of these issues are easily fixed.
Sometimes excess water on your lawn is unavoidable, such as with heavy rain or localized flooding.
A common mistake many homeowners make is overwatering their lawn.
Your lawn only needs around 1″ inch of water once per week, even during the peak of the growing season, to stay lush and green.
If you add too much water to your lawn at one time, or you frequently water with not enough water, your grassroots will be too shallow.
Improper mowing habits, such as mowing a wet lawn or cutting too much grass at one time, will also cause excess lawn thatch to build up.
With more shallow roots, thatch will quickly take hold of your entire lawn unless you develop better lawn care habits.
Below are some of the most common reasons why your lawn is spongy from retaining excess water.
Too Much Thatch
As previously stated, allowing thatch to build up thicker than 3/4″ of an inch will cause any water your lawn receives to stay above the soil.
To check the thatch layer for your lawn, dig up a small piece of your grass at least 2″ inches deep and measure the thatch layer between the grass and the soil.
If the thatch layer is allowed to become too thick, it will be more difficult to remove without causing damage to your yard.
If the thatch is not maintained at least once or twice per year, your grass will remain in poor condition, and your lawn will never be as lush and green as you would like.
Low spots in your yard are another cause for concern when it comes to having a squishy lawn.
These low-lying areas will cause water to pool, creating soggy spots where grass will eventually stop growing because it is too water-logged.
Once the low parts of your yard are completely saturated, excess water will start to seep into nearby areas.
These soggy patches will be more prone to fungus and other diseases.
Having standing pools of water on your lawn may also contribute to increasing your local pest population, especially mosquitoes.
The grass will not survive in an overly saturated low spot, and the ground will become muddy.
Soil with a High Clay Content
Another issue causing your lawn to be spongy is the content of your soil.
Heavy clay soils usually have drainage issues, and this causes water to pool on the surface.
If your soil has a lot of organic material, it will retain a lot of water and leave the ground spongy.
A soil test will tell you what your ground is missing.
While it is possible to fix some drainage issues by adding sand to your lawn, it is better to leave the work to professionals.
Adding amendments to clay-rich soil may be complicated, and if you add sand to the wrong type of clay soil, you will end up with a rock-hard and compacted lawn.
Poor Soil Drainage
If you have clogged gutters or an overflowing drainage spout, you will likely end up with water pooling in your yard.
The problem is made even worse if the water has nowhere to go.
Without a proper drainage system, your lawn will become water-logged every time it rains.
All of this excess water will soften the soil and give your lawn a squishy, spongy feel.
Drainage issues are serious and often complicated, so it is best to hire a garden professional to fix the problem for you.
Drainage ditches may be needed, but they don’t always look good.
Check out these beautiful ideas for making your drainage ditch look good.
How To Fix A Spongy Lawn
It will take a lot of time and effort to completely transform a soft, spongy lawn into lush, green grass.
You will be able to handle several things yourself, but if the issue is highly complex, it is better to hire a lawn care specialist to do the work.
If you are doing the work yourself, do your research and develop a solid plan of action to solve the problem.
Any large equipment you need to use may be rented from your local hardware store or garden center, which will make the job much easier.
The first step to fixing a squishy lawn involves removing the thick layers of lawn thatch accumulated.
The best time to remove excess thatch in lawns is just before the peak of the growing season.
For cool-season grasses, remove thatch in the early spring or late summer.
Since a lot of cool-season grass has another period of rapid growth in the fall, you may also want to dethatch in early fall as well.
For warm-season grass types, it is best to dethatch in late spring.
Use a metal thatch rake or rent an electric dethatcher to remove all thatch from your lawn.
You will need to aggressively rake the ground to pull up all of the decomposing organic material completely.
If your thatch is thicker than 1/2″ inch, a dethatching machine is the best tool for the job.
To thoroughly remove the thatch, you will need to run the dethatching machine across your yard in one direction and then go over your yard again from the other direction.
When the thatch has been uprooted from the ground, you may either add it to your compost pile or discard the debris in a municipal compost site if there is one in your area.
Removing thatch usually solves most issues with a spongy lawn, but you will still have some work to do if there are other issues at play.
Add a Drainage Line or Repair the Existing One
If you have poor drainage in your yard, you may need to add a drainage trench to allow water flow to drain away from your lawn.
A drainage line takes careful planning because you need to ensure enough elevation in your lawn for the water to run downhill.
A French drain is the most effective way to remove excess water from your lawn.
Unlike traditional surface drains, a French drain collects water over the entire length of the trench instead of in one specific area.
French drains are created by digging a trench and filling it with gravel and a length of perforated pipe.
It is easy enough to install a French drain yourself as long as you have done some careful planning, but you may need to consult a professional if your drainage issue is more complicated.
We have a guide on how to dig a trench for drainage if you want to learn more.
Fill Low-Lying Areas
Shallow holes and dents in your lawn tend to collect water every time it rains.
Filling in these low-lying areas will keep you from having a squishy lawn by preventing the water from pooling up in the first place.
Areas of dead grass may erode enough to leave shallow dips in your lawn.
It is essential to level as much of your yard as possible to completely get rid of any trouble spots.
To fill in a hole in your yard, first, you will need to carefully remove any existing patches of grass in or near the hole and set them aside.
Fill the hole with a sand and soil mixture for better drainage in the future, and be sure to mound the dirt up at least 1″ inch higher than the surrounding area.
Replace the grass, gently tap it into place, and water the area to stimulate contact between the grassroots and the soil.
The dirt will eventually settle, and the filled-in area will have the same soil level as the rest of the lawn.
Aerate Your Soil
Tightly compacted soil will not only encourage thatch and inhibit lawn drainage, but it will also prevent your grass from receiving the moisture and nutrients it needs at the roots.
If you have removed the thatch and fixed drainage issues but are still dealing with a spongy lawn, you will need to aerate your soil.
Core aeration is an excellent solution because it creates holes in your lawn, exposing the soil to air.
These holes allow water to penetrate the ground and give your soil the air exposure it needs to dry out when it needs to instead of retaining every last drop of water.
As a result, your spongy lawn will firm up again, and your grass will grow healthier as it receives more nutrients and moisture.
Commonly Asked Questions
Why is my new sod squishy?
If you have recently installed new sod and your lawn feels spongy and squishy, it is likely because the sod has been overwatered.
It takes up to three weeks for the sod’s roots to grow into the ground, and the sod will need to be irrigated thoroughly during this time.
However, adding too much water will cause the water to pool underneath the sod, and you will have a spongy lawn.
If you peel the sod away and discover brown and soggy roots, they rot because of too much water.
Take care not to add lots of water to your sod until the grass roots have established themselves into your lawn.
The area of sod needs to be kept moist, but there should not be standing pools of water.
How do you fix soggy sod?
Give your new turf a chance to recover by staying off of your lawn and allowing the areas of sod to dry out a bit.
Clear your lawn from any debris which may contribute to fungus or diseases in the wet environment.
Once your sod is no longer squishy, you may resume your regular lawn care routine and add fertilizer.
Never attempt to mow soggy or squishy sod because the weight of your lawnmower may cause ruts in your lawn.
These ruts will only exacerbate the problem by allowing more water to pool on your lawn.
If ruts are a problem for you, we have a post on how you can fix ruts in your lawn you should check out.
Does sand help soggy grass?
Sand may be added to the holes left after core aeration to give the soil better drainage properties.
However, adding sand on top of your lawn and hoping to achieve the same results is usually a bad idea.
Even if you are using specially formulated lawn sand, applying it on top of your lawn may lead to further drainage problems and dry pockets in the soil.