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Compacted Soil

How to Identify, Treat and Prevent Lawn Compaction

A lush, healthy lawn needs air, water and nutrients to reach the roots. When soil becomes compacted, these essentials struggle to get through, resulting in patchy, thinning or waterlogged grass. Compacted soil is one of the most common lawn problems, but it’s also one of the easiest to fix with regular care and aeration.

What Causes Soil Compaction

Soil compaction happens when soil particles are pressed tightly together, reducing the space between them. This prevents air, water and nutrients from moving freely through the soil, starving the grass roots below.

Common causes include:

  • Heavy foot traffic or pet use – Frequent walking, playing or machinery compresses the soil.

  • Wet weather use – Walking or mowing on wet ground pushes soil particles together.

  • Clay-based soil – Naturally dense and prone to compacting, especially during dry spells.

  • Lack of aeration – Without regular aeration, the soil structure deteriorates over time.

As a result the grass becomes thin, patchy, and pale green, while puddles or moss may appear after rain... clear signs your lawn is struggling to breathe.

drought and unevenly watered lawn

How to treat compacted soil

Step 1: Test the soil

If water sits on the surface or it’s difficult to push a garden fork into the ground, your soil is compacted.

Step 2: Aerate the lawn

Use a garden fork, hollow-tine aerator, or mechanical aerator to create holes 10–15cm (4–6in) deep across the surface. For best results, do this in spring or autumn when the ground is moist but not wet.

  • For small lawns: A garden fork works well — simply insert and gently rock it back to open the soil.

  • For larger lawns: Use a hollow-tine aerator to remove small plugs of soil and relieve deeper compaction.

Step 3: Top dress the surface

After aerating, brush a top dressing of sand, loam or compost into the holes. This improves soil structure, aids drainage, and keeps the holes open longer.

Step 4: Feed and overseed

Apply a suitable lawn feed to boost recovery, then overseed with a quality seed mix such as Johnsons General Purpose Lawn Seed to thicken the grass and prevent weeds or moss from taking hold.

Step 5: Water regularly (but not excessively)

Keep the area evenly moist to help new roots establish, avoiding overwatering which can worsen compaction in clay soils.

Preventing Lawn Compaction

  • Aerate annually – Especially in high-traffic or clay areas.

  • Avoid walking on wet lawns – Wait until the ground has dried after rain.

 

  • Use stepping stones or paths in heavily used areas to protect grass.

  • Mow regularly, but lightly – Avoid heavy mowers or rolling during wet weather.

  • Overseed every year to maintain a thick, resilient sward that resists wear.

  • ​Regular maintenance ensures your soil stays open, oxygenated, and free-draining — helping roots grow deeper and your lawn stay greener for longer.

 

The All-Round Seed For Tough Conditions

General Purpose