How to Fix Compacted Soil

Aeration, digging, and tilling can temporarily treat soil compaction. For a long-term fix, provide the soil with organic matter, cover, keep the soil planted, and have a healthy soil microbiome. Avoid compacting it further, and it will gradually cure itself. 

What is Compacted Soil?

Compacted soil has fewer and smaller pores for air and water movement because its particles are pressed tightly together. It’s dense and heavy, limiting nutrient absorption and root growth. 

In lawns, gardens, and crop fields, soil compaction leads to poor germination and thin, weak plants that grow slowly and are more prone to diseases and pests.

7 Ways to Fix Compacted Soil

1. Aerate the Soil

An easy, fast fix for compacted soil is to break the hard layer of dirt with core aeration, liquid aeration, a fork, or a shovel. 

Aeration makes tiny holes in the soil that improve absorption and drainage. It also loosens the soil structure, helping roots stretch out easier. You can aerate your lawn with a broad fork, a garden fork, or a manual aerator, but large areas are more manageable with a powered tool.

Here’s how to choose:

• A core aerator is the best option, especially for severe compaction. 
• A spike aerator works fine if compaction is mild. 
• Liquid aeration is recommended for light and mild compaction. In this case, you’ll use a garden pump sprayer or hose-end sprayer.
• If the compacted layer is more than 4 inches deep, you might need a deep-tine aerator (with tines up to 12 inches deep) or a tiller.

Sometimes, the soil is so tough that regular home-use aerators bounce off the ground and barely chip the dirt. If your lawn is too hard to aerate, you might need to dig it up with a shovel or a rototiller. 

Don’t over-till, though. It can make compaction worse. Till once to loosen the packed dirt, then focus on adding organic matter and keeping the soil covered.

Note: Always aerate or dig on moist but not wet soil since working on wet soil can lead to further compaction. Wet soil has visible moisture at the surface and sticks together and to your hand. Moist soil has less moisture but still enough to allow you to form it into a ball.  

Related articles:

• “Core Aeration vs. Spike Aeration: What’s the Difference?”
• “How Much Does Lawn Aeration Cost in 2024?”
• “When and How Often Should You Aerate Your Lawn?”

2. Add Compost

Compost improves the soil texture by adding organic matter.

Organic matter acts as a binding agent, allowing soil particles to form small clumps and create openings in the soil. Mixing compost into your soil is the easiest way to add organic matter. 

Experts at the University of Florida say that a 1-inch layer of compost incorporated while tilling is usually enough to improve the top 6 inches of soil. You can also add it as topdressing, though it is less effective in treating soil compaction, and the effects will be slower.

Note: You can make compost at home from kitchen scraps, fallen leaves, and grass clippings. 

3. Cover the Soil with Mulch

A thick layer of mulch keeps the soil in garden beds shaded, moist, and protected from extreme temperatures. It also leaks organic matter into the ground — a heaven for earthworms and other underground life that work on softening the soil. 

Spread 2 to 3 inches of mulch on garden beds. On lawns, leave the grass clippings as mulch, but make sure the layer is no more than 1 inch thick.

What kind of mulch? You can use straw mulch, dry leaves, wood bark, or grass clippings. My favorite mulch is grass clippings trimmed short. I keep a thick layer on my veggie beds during summer because it’s the only way to keep our clay-rich soil moist and fluffy. 

Related articles:

• “How Much Does Mulch Cost?”
• “How Often Should You Replace Mulch?”
• “Where to Get Free Mulch”

4. Attract Earthworms

Earthworms are natural soil aerators and a trustworthy indicator of soil health: the more you find, the healthier and fluffier the soil.

These diligent ground diggers create tunnels, loosen the soil, and burrow deep, breaking openings into hardpans. They also drag leaves and other litter into the deeper layers, where fungi and bacteria can decompose the organic matter.

Earthworms are also migratory. They go where they find proper food and shelter. 

If you create a moist, nourishing habitat, they will magically appear. To attract earthworms and keep them happily working the soil, add compost periodically and keep the area covered in mulch. They’ll slowly get into the hard layer of soil, breaking it and mixing in organic matter.

5. Keep the Soil Planted

What else can naturally break compacted soil? Groundcovers with extensive root systems and taproots.

Plant roots are great when you need to repair soil compaction. They dig into the ground and enlarge any openings, improving the soil structure. Some stubborn taproot plants, like dandelions and plantain, can even break heavily compacted soil you have difficulty splitting with a shovel.

Groundcovers also improve soil health by keeping it shaded and moist. Dead leaves, stems, and roots decompose into organic matter, providing soil life with precious food.

Some species that can help you solve the compaction problem are:

• Daikon radishes
• Dandelions (trim the flowers before seeding to avoid spreading)
• Alfalfa
• Chicory
• Fenugreek
• Comfrey
• Yarrow
• Mustard

Look for plants adapted to the local climate and soil. If your yard has waterlogged areas (causing compaction), plant species that can handle damp soil.

6. Use Gypsum Wisely

Gypsum only works for certain types of soils.

According to experts at Louisiana State University, gypsum can alleviate compaction only in soils rich in clay or sodium. “Adding gypsum to sandy or nonsodic soils (low in sodium) is a waste of money and natural resources and can have negative impacts on plant, soil, and ecosystem health.” 

Before applying gypsum to compacted soil, talk with the local Extension Office experts to ensure it’s the right choice.

7. Replace the Soil

To treat severe compaction quickly, remove the hard soil and replace it with a better one.

This is the most aggressive and expensive approach. It is helpful when planting a shrub or a tree, and you must treat the compaction in a limited area. You excavate the compacted soil and then fill the hole with garden soil.

Find out how deep and wide the roots will grow, and make sure you fill enough space with loose, fertile soil to ensure the plants’ growth.

How to Prevent Compaction

Fixing soil compaction can be difficult, so to keep this soil problem from returning, avoid habits that can compact the ground:

• Reduce tilling as much as possible.
• Don’t work or walk on wet soil.
• Install walkways, fences, and shrubs to redirect foot traffic out of compacted areas.
• Keep heavy equipment away from your lawn and garden beds.
• Eliminate areas where water may accumulate (fill in low spots, redirect downspouts).

FAQ About Fixing Compacted Soil

How to Fix Compacted Soil in Pots?

To fix compacted soil in pots:

• Add organic matter (compost, vermicompost, peat moss).
• Loosen the soil with a chopstick or a garden fork.
• Mix in soil amendments such as perlite or vermiculite.

How to Fix Compacted Soil Around Trees?

To fix compacted soil around trees with minimal harm to the roots, dig trenches from the trunk to the drip line, similar to the spokes of a bicycle wheel. Make them 4 to 6 inches wide and 12 inches deep. Fill the trenches with coarse gravel and cover with topsoil. 

What is best to fix compacted soil – aeration or tilling? 

Core aeration is often the best option. It is less invasive to the soil structure and existing plants. 

Tilling is helpful if the soil is too hard for aeration, the compaction is too deep, or you must mix in organic matter. However, tillage breaks the soil texture, can worsen compaction, and should be used only when necessary.  

Get a Professional Fix for Your Compacted Lawn

Soil compaction suffocates your beautiful turfgrass and turns it thin and yellow. Find a lawn care professional with LawnStarter to fix the compacted soil and restore your grass’s healthy green.

Main Photo Credit: U.S. Department of Agriculture / Flickr