Aerating a lawn is an often under-considered component in lawn care. The way in which a gardener aerates, either by spike or plug aeration, can affect the health of the lawn. Both the spike and plug aerators perform the same task; however, there are differences in the efficacy and the cost between the two tools that the lawn owner may wish to consider.
By aerating, water penetration is improved, thereby watering roots deeper. Fertilizer moves more effectively to the deeper root base, and oxygen and carbon dioxide exchange becomes more efficient. The results of aerating lawns are healthier, brighter and greener lawns.
Plug aerators, also called core aerators, remove a solid core about 1 inch in diameter and a length of anywhere between one to six inches in depth, and two to four inches apart, depending upon the aerator. Once the plugs are removed, the empty space can be lightly filled with composting mix and/or fresh seeds. The lawn can therefore re-oxygenate and fertilizer can move deeper into the root base.
Spike aerators, while performing the same act as the plug or core aerators by separating and breaking up the thatch, have the unfortunate after-effect of compacting the soil. Instead of removing a plug of thatch and soil, the thatch and soil is simply compacted around the spike, thereby allowing the material to revert to its original state after a couple of waterings.
One additional consideration, as the Kansas State University Horticultural Report states, is that by using the spike aerating method, the "turf heals quicker than with core aeration because no soil is being removed." The effects of spike aeration may be short-term, but results in less destruction.
For most gardeners, cost is a major consideration in determining if spike or plug aeration will be used. Spike aerators can run as little as $10 for a set of spikes to put around your shoes. Many home gardeners prefer this inexpensive alternative, especially those with smaller patches of lawn. Plug aerators can run over $400.
Large lawns benefit from plug, or core aerators, but for the small lawn owner, spike aeration can make good sense. According to the University of Georgia Cooperative Extension, a "solid spike aerator is better than nothing but inferior to the hollow core aerator." One alternative would be to rent a plug aerator.
Areas of heavy clay or rocky areas are difficult to aerate. When using an aeration tool, always flag sprinkler heads to make sure they are not run over.