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How to Soften a Hard Soil Lawn

plowed soil close up arable land soil plowed new season How to Soften a Hard Soil Lawn

The ideal lawn should be soft and thick–maybe even luxurious–to walk or sit on. Compacted lawn soil makes it more like walking or sitting on the sidewalk. 

There are many ways to loosen compacted soil. Aeration, lawn additives, watering, and in some cases, cultivation will soften hard soil. Softer soil promotes oxygen and water penetration, and healthy root growth. And your lawn will begin to look healthy again.

Just pouring water and fertilizer onto a sick lawn will not repair it. Fixing the soil structure first will make your lawn maintenance plan more effective. 

Read about more ways to soften the soil and improve the health and looks of your lawn.

underground soil layer cross section earth with grass top with white background How to Soften a Hard Soil Lawn
Cross section of lawn

How Soil Becomes Compacted

Very healthy soil is made up of a 50/50 combination of soil particles and pores (tiny air pockets). The air pockets allow roots to find moisture and nutrients and provide space for the root system to easily grow and expand.

Compaction prevents all of this. Roots can’t penetrate the soil. Water runs off. Fertilizer can’t be absorbed. What causes soil that is hard? 

  • Heavy Foot Traffic. Hard lawn soil is created by people constantly walking on the same parts of the grass.
  • Vehicle Traffic. Driving on the lawn–or even worse, parking on the lawn–will squeeze the air pockets out quicker than anything else. Even lawnmowers using the same tracks will compact soil.
  • Heavy Use. Soil is compacted around firepits, kid’s play areas, and anywhere gatherings take place.
  • Heavy Rain. Heavy rain or overwatering combined with walking, mowing, or driving on still-wet lawns hastens compaction.
  • Aging and Gravity. Gravity continuously exerts downward pressure. Over time–especially without regular care–the soil becomes hard.
  • Clay Soil. Clay is a soil type that is easily compacted. The particles are so tiny they can easily be pushed tightly together.

Note: Even though it seems to make sense, do not mix sand into your clay soil trying to loosen it up. Michigan State University states “The soil can become like concrete.”

Impacts of Hard Soil

Compacted soil prevents roots from absorbing nutrients and moisture to feed the plant. Eventually, it will die from a lack of nourishment.

How to Recognize Compacted Soil

Some of the signs of compacted soil include:

  • Water pooling on the lawn
  • Yellowing grass blades
  • Shallow root structures
  • Thinning grass
  • Slow growth and fewer new shoots

Soften Compacted Soil

By using one of the following ways to soften soil, your lawn will start to look good again.

Core Aerate Your Lawn

Using a core aerator is one of the quickest and most effective ways to loosen the soil. It removes plugs of soil about 3/4″ in diameter and up to 3″ long–usually 3 – 4 inches apart. Water, oxygen, fertilizer, and/or topdressing get deeper into the soil. The plugs fall apart and decompose after a rain or two.

Machine aerators can usually be rented from home improvement stores, rental outlets, and (occasionally) garden centers. You can also use a manual aerator, which looks like a two or three-tine fork that you jump on to aerate the lawn. Consider this a small area piece of equipment.

Another aeration option is a spike aerator that you can strap to your shoes. Aerate and mow at the same time. If your lawn is wet and soft, you may do more harm than good.

Liquid Lawn Aeration

Liquid lawn aerators are applied with a garden sprayer or garden hose sprayer. Many of them–like the one pictured–are advertised as dethatchers/aerators. Follow container directions but expect to need more than one application. 

Liquid Lawn aerators take longer to work, may require numerous applications, and probably will not work well–or at all–on hard clay soil. Because of the amount required, liquid aerators could end up being more expensive.

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Courtesy: amazon.com – Liquid dethatcher and aerator

Dethatch Your Lawn

Lawns should be dethatched any time the thatch gets to be over an inch thick. To get the most out of aeration and soil loosening, dethatch your lawn first. 

Dethatching allows the aerator to go deeper. Little or no thatch leaves the holes clean for water, fertilizer, and topdressing to get deep into hard lawn soil.

Add Gypsum to Your Lawn

Maybe! Those that recommend gypsum really like it. Linda Chalker-Scott Ph.D. Horticulturist states “Urban soils are heavily compacted and layered (and gypsum does not work well on layered soils).”

Gypsum is also slow-acting. It may be more cost-effective to use organic topdressing such as compost or manure to repair compacted soil.

Topdress your Lawn

Topdressing your lawn with compost or organic matter like manure will attract earthworms that tunnel through the soil and leave castings of semi-digested material. The organic matter will also break down and be absorbed by the existing hard soil.

Note: For quick earthworm cultivation, buy some from one of the many commercial worm farms worldwide.

Over time the water and nutrients will be incorporated into the soil surface and soften and loosen it. Regular topdressing and patience are good ways to soften the soil. Your grass also becomes more healthy.

Note: Topdressing is much more effective after aeration and dethatching because water, oxygen, fertilizer, and topdressing penetrate easier and deeper.

Cultivate Your Lawn 

If you have tried everything and your lawn is still the consistency of concrete, you may have to turn it over. A heavy-duty rear tine rototiller should be able to get down at least 6 – 8 inches. Once it is torn open add 2 or 3 inches of compost or manure and mix it up. (I also add straw to our garden for added tilth. 8 square bales for 6000 square feet.)

Add lime to the mixture if your soil tester shows a pH of less than 6.5. Rake smooth, pack lightly, add fertilizer, and either reseed or sod the lawn.

soil moisture meter

Courtesy: amazon.com – 4 in 1 soil testing meter

Lawn Maintenance to Prevent Soil Compaction

Reduce compaction by following these suggestions.

  • Aerate yearly. Core aerate every year. Late summer is best.
  • Topdress Yearly. Topdress with compost after aeration for improved microbial action and drainage.
  • Water Regularly. Use a sprinkler and water until saturated–not soaked and muddy. Do not walk on or mow the lawn wet.
  • Dethatch Regularly. Dethatching is usually not required yearly. Often every 3 – 5 years. Do not allow thatch to exceed one inch.
  • Leave Grass Longer. Longer grass protects the soil from foot traffic compaction.