Core aeration is a process that removes thousands of plugs of soil from your lawn. These soil plugs are usually 1-3" long. Core aeration is done with a core aerator machine. Core aerators have hollow tines arranged around shaft or drum. As the machine moves across a lawn, hollow core aeration tines penetrate the soil and extracts plugs of soil.
There are a number of benefits to core aerating your lawn on an annual basis.