The process of lawn aeration involves extracting cores of soil from the lawn area. It is a standard contractor technique for ground-maintenance professionals. In the context of landscape and lawn maintenance, aerate means “to supply with air.” This is accomplished with a device that has hollow teeth or tines. These machines are available in walk-behind models, or can be towed behind a tractor. As the machine's drum spins, the blades or “pluggers” cut into or remove cores of soil. With core aerators, the extracted plugs of soil range from 1/4 to 3/4 inch in diameter and 2 to 4 inches in depth. The process of aeration serves a two-fold purpose: It helps control thatch development and reduces compaction on the surface of the soil.