What is lawn aeration?
Lawn aeration involves the removal of small soil plugs or cores out of the lawn. Although hand aerators are available, most aeration is done mechanically with a machine having hollow tines or spoons mounted on a disk or drum. Known as a core aerator, it extracts 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 aerators push solid spikes or tines into the soil without removing a plug (spiking). These are not 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.
What will aeration do for my lawn?
As lawns age or sustain heavy use from play, sports activities, pets, vehicle traffic and parking, soil compaction can result. Soil compacting forces are most severe in poorly drained or wet sites. Compaction greatly reduces the pore space within the soil that would normally hold air. Roots require oxygen to grow and absorb nutrients and water. Compaction reduces total pore space and the amount of air within the soil. It has a negative impact on nutrient uptake and water infiltration, in addition to being a physical barrier to root growth. This results in poor top growth and lawn deterioration. Core aeration can benefit your lawn by:
How do I know if I need to aerate?
If in doubt about aeration, remove a square foot section of lawn at least 6 inches deep. If grass roots extend only into the first 1-2 inches, your soil may be compacted and could benefit from core aeration. Expect a seasonal effect with cool-season grass roots being shortest in late summer and at their greatest depth in late spring.
Other reasons to aerate include:
Is there any reason not to aerate?
A lawn that is not exposed to soil compacting events will likely grow well and may not need aerification. Winter freezing and thawing cycles and earthworm activity can help loosen slightly compacted soils. If the lawn has a thatch layer in excess of 1/2 inch, then core cultivation can be used as a preventative approach to control excess thatch build up. Newly seeded or sodded lawns should not be aerated in the first year.
When should I aerate?
In Virginia, the best time to aerate cool season lawns of tall fescue and Kentucky bluegrass is in late August to mid September. This is when these lawns are coming out of summer dormancy and beginning a period of vigorous growth. Lawns will recover quickly from aeration at this time. Competition from weeds is also minimal during this time. Warm season lawns like bermudagrass and zoysiagrass are best aerated during June and July, as this is their period of rapid growth.
Where can I get an aerator?
Aerators may be rented at many garden or rental centers. Some lawn or landscape companies will perform the service for a fee. Be sure that the machine has hollow tines or spoons to bring the soil core to the surface. Look for machines with deeper tines and weight over the tines for better penetration into the soil. Busy rental times include most spring and fall weekends; reserve early or plan on weekday use. These machines are large and heavy; they will require special handling and larger vehicles for transport. Many people cooperate with neighbors and make it a group effort, thereby also lowering the overall cost. If renting, be sure you are instructed in and comfortable with the operation of the machine before bringing it home.
How do I aerate?
What else do I need to know?