What is aeration?
Aeration is the naturally occurring process of air exchange between the soil and its surrounding atmosphere. It is also the process of mechanically removing small plugs of thatch and soil from the lawn to improve soil aeration. Textbooks often refer to the practices of soil aeration as soil cultivation (coring, spiking and slicing).
Aeration refers to the opening of the sod mat to the atmosphere. An aerator is a machine that pulls finger-sized plugs of grass and soil from your lawn. These holes then allow air, water, and fertilizers to readily enter the lawn. Aeration works great on hard compacted lawns and should be done once a year, in the spring.
