The most common and effective lawn aerator is known as a core aerator. It which uses hollow tines that remove soil cores from the ground. To understand this concept, let's take a look at the design of a manual core aerator.
Manual Core Aerator
The soil cores are "punched out" every time the aerator is stepped into the ground. The procedure is rather simple; the operator only needs to step and pull, as shown in the two pictures above. The soil cores should be left on the ground because they will help decompose grass clippings and thatch. The soil cores will also fill low spots in the yard to smooth out minor unevenness. The procedure looks easy too, until you have to do it several thousand times, making manual core aerators suitable for small areas only.
Gas-powered core aerators are more practical and can cover larger areas. These aerators are used by lawn care professionals and available for rent at most rental stores. Since they are used about twice a year only and cost about US$2,500 or more, very few homeowners should consider buying one. Popular brands are Bluebird, Ryan, Classen, and Turfco.
Ryan (A Commercial) Core Aerator
Homeowners who own garden tillers may have an additional option. There is an attachment that converts garden tillers into core aerators.
Aeroller lawn aerator attachment for front-tine garden tillers