When buying a lawn aerator, you should consider how seriously your lawn needs aeration and how much elbow grease you are prepared to put into the chore. Aeration allows soil exposure to air, which keeps your lawn from looking thin, brown, or matted. Different kinds of lawn aerators span a wide range of costs, ease of operation, and efficiency with which they aerate your lawn.
One thing to consider when buying a lawn aerator is how much your lawn needs aeration. Certain types of grass tend to mat together and not allow water, fertilizers, and sunlight to reach the soil. Clay soil tightly compacts and has poor drainage, while sandy soil requires less frequent aeration.
If your lawn is generally healthy, consider getting aeration shoes. These strange looking sandals have an array of sharp, triangular spikes on their soles. They strap onto your regular shoes and for a small investment, they can contribute to a lush lawn. For people who are already out in their yard several times a week, lawn aerator shoes are a great choice. They give you exercise and provide a continuous, yet less powerful, method of spike aeration.
Seasonal treatments for your lawn, such as fertilization, seeding, and aeration, can also be accomplished in one easy step. If you only want to be bothered with major lawn care twice a year, you can consider investing in a hefty lawn maintenance equipment called a plug or coring aerator. This massive, wide, automated tool actually cores your lawn and removes small plugs of soil from the ground so there are noticeable holes.
A coring aerator is a good choice if you are maintaining an area that gets an extreme amount of traffic such as a playground, sports field, or dog park. In these instances, considering the amount of stress the turf is under, this more dramatic lawn aerator may be worth the cost. For a small, personal lawn, this method may be prohibitively expensive and unnecessary. Consider renting this tool once or twice a year.
There is an option that offers a compromise between those two tools to give a semi-automated yet efficient method of aeration. A rotary spike lawn aerator resembles a push mower piled with giant cement blocks to give it enough weight to penetrate a compact lawn. This would be appropriate if you don't have as much storage space or as large a budget as you'd need for a coring aerator, but you need something larger than spike sandals.