Lawn aeration is the removal of small soil plugs or cores out of the lawn. Although hand aerators are the most popular on small/medium sized lawns, aeration is also done mechanically with a machine having hollow tines or spoons mounted on a disk or drum. These are a core aerators, and extract 1/2 to 3/4 inch diameter cores of soil and deposits them on your lawn. Aeration holes are typically 1-6 inches deep and 2-6 inches apart. Other types of manual aerators push solid spikes or tines into the soil without removing a plug (spiking). These are not quite as effective because they can contribute to compaction. Core aeration is a recommended lawn care practice on compacted, heavily used turf and to control thatch buildup.