What Is Core Aeration?
Core aeration for your lawn cultivates soil much in the same way that garden soil is cultivated: By creating holes in the soil water, air and nutrients can easily enter. You can expect vigorous root growth thanks to the increased penetration of air into the soil.
Core aeration also helps control thatch, but it can’t fix a severe thatch problem on its own without an aggressive turf grass management program. It can also be combined with overseeding.
How Does Core Aeration Work?
During aeration, a machine is used to extract plugs of turf, thatch and soil, creating holes in your lawn. The plugs are deposited on the surface. This process:
- Increases gas exchange in the root zone
- Improves penetration of moisture and nutrients
- Stimulates root growth
- Relieves compaction
- Helps manage thatch and prevents excessive buildup
Lawn Care Basics: Soil Moisture and Core Depth
When’s the Best Time to Aerate Your Lawn?
Aeration should be performed only when the conditions are right for active root growth in order to not cause any undue stress on your lawn. These conditions depend on whether you have warm-season or cool-season grass. Follow the lawn care tips based on your type of grass:
- Warm-season grass. The best time for warm-season grass aeration is during the summer months between spring green-up and fall transition. Never perform aeration on this type of grass during spring, winter dormancy or fall transition.
- Cool-season grass. Fall aerations are preferred. When performed in the late fall, recovery should take place before dormancy. Spring aeration is acceptable as well, but it may impact the performance of preemergence herbicides. Never perform core aeration on cool-season grass during the summer heat or winter dormancy.
What Is Thatch?
Thatch is a layer of slowly decaying organic matter composed of dead roots, stolons, leaves, rhizomes and other grass plant parts. This layer rests right above the surface of the soil and can either be beneficial or detrimental, depending on its depth. Detrimental thatch levels can increase insect and disease problems; decrease tolerance to heat, cold and drought; and prevent moisture from getting to the soil.
The key to core aeration rests in starting the program before thatch levels are excessive. Generally speaking, ½ to ¾ of an inch of thatch is healthy for your lawn—anything over 1 inch can reduce the quality of your grass. Aeration should be used to maintain healthy levels—for any thatch levels in excess, more frequent and aggressive lawn maintenance programs might be needed.