The Benefits of Aerating Your Lawn

• The benefits of Aeration
• Why is Aeration necessary?
• When should lawns be aerated?

What is Aeration?

Technically speaking, aeration is the natural exchange of soil and air. Practically speaking, aeration is the process of mechanically removing small plugs of thatch and soil from the lawn to improve soil aeration.

Textbooks often refer to the practices of soil aeration as soil cultivation (coring, spiking and slicing). The aeration process is also commonly called core aeration in the lawn service industry, and homeowners often refer to it as aeration.

What are the benefits of Aeration?
Core aeration helps the lawn's health and vigor, and it reduces maintenance requirements. The following are benefits of core aeration.

• Improves the exchange between the soil and atmosphere.
• Increases water intake.
• Reduces water runoff and puddling.
• Stimulates root development.
• Reduced soil compaction.
• Increases the tolerance to heat and drought stress.
• Improved resiliency and cushioning.
• Enhanced thatch breakdown.

The type of aeration equipment used influences the benefits obtained from aeration. Equipment with hollow tines removes soil cores. Aeration equipment varies in tine size up ¾ inch and in depth of penetration up to 3 inches, depending on the manufacturer's specifications.

Penetration depth depends on soil type, soil moisture, tine diameter, and the weight and power of the aerator. For example, tines penetrate sandy soils easier than they penetrate heavy clay soils, and penetration is better in moist soils than dry soils. Turf responds best when core holes are close and deep.

A ¾ inch aeration tine with 6 inch spacing and penetrating depth of 3 inches
removes about 1.2 percent of the soil's volume in that 3 inch profile. The same tine spaced 2 inches apart removes about 10 percent of the soil in the same 3 inch profile. The closer tine placement removes more soil, exposes more soil surface area for water and fertilizer uptake, and it alleviates compaction quicker than the wider tine spacing.

Why is Aeration necessary?

In most home lawns, the natural soil has been seriously disturbed by the building process. Fertile topsoil may have been removed or buried during excavation of the basement or footings, leaving subsoil that is more compact, higher in clay content and less desirable for healthy lawn growth. These lawns need aeration to improve the depth and extent of turfgrass rooting and to improve fertilizer and water use.

Intensively used lawns are exposed to stress from traffic injury. Walking, playing and mowing are forms of traffic that compact soil and stress lawns. Raindrops and irrigation increase soil density. By compacting soil particles and reducing large air spaces where roots may readily grow.

Compaction is greater on heavy clay soils than on sandy soils, and it is greatest in the upper 1 to 1-1/2 inches of soil. Aeration helps heavily used lawn and lawns growing on compacted soils by improving the depth and extent of turfgrass rooting, allowing better water uptake, enhancing fertilizer use and speeding up thatch breakdown.

Most home lawns are subject to thatch accumulation. If thatch is left unmanaged, it can lead to serious maintenance and pest problems. For example, thatch accumulation of more than ½ inch on Kentucky bluegrass lawn impedes water, fertilizer and pesticide effectiveness. Core aerator reduces thatch accumulation, minimizes its buildup and modifies its makeup by incorporating soil into the thatch. As soil combines with the thatch debris, soil organisms are better able to break down the thatch and reduces its accumulation.

Thatch accumulates faster on compacted soils, heavy clay soils, and subsoil's that are disturbed during building processes, than on well-aerated soils. Therefore, lawns require frequent aeration to prevent that buildup. Most home lawn growing on heavy clay or highly compacted soils require annual or multiple aeration to restrict thatch accumulation.

Thatch accumulates faster on compacted soils, heavy clay soils and subsoil's that are disturbed during building processes, than on well-aerated soils. Therefore, lawns require frequent aeration to prevent that buildup. Most home lawn growing on heavy clay or highly compacted soils require annual or multiple aeration to restrict thatch accumulation.

When should lawns be aerated?

Annual aeration is beneficial for most lawns. Lawns growing on heavy clay or subsoil's, and lawns exposed to intense use benefit from more than one aeration each year.

Both spring and fall are ideal times to aerate cool season turfgrass such as Kentucky bluegrass and perennial ryegrass. In most cases, spring aeration is performed between March- May, depending on locations, turfgrass species and intensity of use. Fall aeration is done in late summer and early fall, usually between August-November. Aeration before or at the time of late season fertilization enhances root growth responses and improves spring greenup and growth.

Applying fertilizer after aeration helps the lawn compete against weeds. Water the lawn after aeration, particularly in areas where drought and high temperatures are common (i.e., along sidewalks and driveways).