How to Break Up Compacted Soil for Grass Seed

There are three common methods to break up compacted soil in a lawn.
A gas-powered mechanical core aerator pulls 1- to 4-inch plugs of soil from the ground, allowing fertilizer, water and lawn roots to permeate the hard soil. A manual core aerator also pulls up soil plugs, but without mechanical assistance. Liquid lawn aerators are applied to the lawn with a hose sprayer attachment.

Things You'll Need

• Rake
• Lawn mower
• Mechanical or manual or liquid lawn/core aerator
• Garden hose and sprayer attachment (for liquid lawn aerator)

Instructions

Mechanical core aerator

1. Rake the lawn to remove leaves and other debris.

2. Mow the lawn.

3. Move the mechanical aerator to the edge of the compacted lawn area; start the aerator.

4. Guide the aerator over the lawn in a grid pattern to ensure that all areas of the lawn are treated. (Some aerators are push-style, others are towed behind a riding mower or tractor.)

5. Leave the soil plugs expelled by the aerator in place. They will break down completely in a couple of weeks, and will fertilize the soil.

Manual core aerators

1. Rake the lawn to remove leaves and other debris.

2. Mow the lawn.

3. Plunge the manual core aerator into the compacted lawn area and pull it out. Move forward a step, plunge the core aerator into the soil again. Repeat this step across the lawn, following a pattern or grid to ensure that the entire lawn is aerated.

4. Leave the soil plugs expelled by the aerator in place. They will break down completely in a couple of weeks, and will fertilize the soil.

Liquid lawn aerator

1. Rake the lawn to remove leaves and debris.

2. Add liquid lawn aerator to the reservoir of the hose sprayer attachment.

3. Turn on the water supply to the hose.

4. Spray the solution over the entire compacted lawn, following a pattern or grid to ensure that the entire lawn is treated.

Tips & Warnings

• Mechanical core aerators are the best, fastest, most effective method for alleviating compaction in large lawns or in very hard, dry soil.

• Because manual core aerator operation requires more muscle, it's best used on rain-softened soils and for smaller lawns.

• Plug aeration should be performed no more than once every three years.

• Liquid lawn aerators are quickly and easily applied, but must be reapplied monthly over the course of the summer and fall until the compaction problem is alleviated.

References

• Soil Compaction: Causes, Effects, and Control
• Lawn Repair and Renovation
• Help your lawn breathe; organic or mechanical treatment?