Equipment Affects the Outcome
The type of aeration equipment can
determine how effective the treatment will be. In general, turf
responds best when core holes are close and deep. Equipment with
hollow tines removes soil cores. Equipment with open tines divots the
soil surface. Aeration equipment also varies in tine size up to 3/4
inch diameter and in depth of penetration up to 4 inches, depending on
the manufacturer's specifications.
Why is Aeration Necessary?
In most home lawns, fertile topsoil may
have been removed or buried during excavation of the basement or
footings, forcing grass to grow in subsoil that is more compact, higher
in clay content, and less likely to sustain a healthy lawn.
Walking, playing and mowing will compact
soil and stress lawns. Raindrops and irrigation further compact the
soil, reducing large air spaces where roots 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 can help relieve soil compaction,
allowing your grass to grow deeper roots and make better use of water
Relieve Thatch Accumulation
Most home laws are subject to thatch
accumulation. Left unmanaged, it impedes water, fertilizer, and
pesticide effectiveness. Core aeration combines soil with the thatch
debris, so organisms are better able to break down the thatch and reduce
How Often Should Lawns Be Aerated?
Most lawns benefit from annual aeration.
Heavily used lawns, or those growing on heavy clay or subsoils, may
need more than one aeration each year. Again, turf responds best when
tine spacing is closer and penetration is deeper.
When is the Best Time to Aerate?
If you have cool season turfgrass such as
Kentucky bluegrass and perennial ryegrass, both spring and fall are
ideal times to aerate. In spring, aerate between March and
May. Perform fall aeration between August and November. Aeration
before or at the time of late season fertilization enhances root growth
and improves spring greenup and growth.
Warm season turfgrasses such
as zoyziagrass and bermudagrass should be aerated in mid-spring to
summer. Avoid aerating when warm season grasses are dormant - it may
encourage weed competition. In addition, avoid aerating warm season
grasses during spring greenup, and not until after their first spring
Herbicides, Fertilizers & Aeration
It's best to aerate before you apply
pre-emergence herbicides, rather than after. Aerating after a herbicide
application can reduce the chemical barrier formed by the herbicide,
allowing weeds to germinate. 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.
What can you expect?
Immediately after aeration, your lawn will
be dotted with small plugs pulled from the soil. Within a week or two,
they break apart and disappear into the lawn.
About 7 to 10 days after aeration, the
aerification holes will be filled with white, actively growing roots - a
sign that the turfgrass is receiving additional oxygen, moisture, and
nutrients from the soil.
On compacted soils and on lawns with
slopes, you should see an immediate difference in water puddling and
runoff after irrigation or rainfall. After aeration, your lawn should
be able to go longer between waterings, without showing sighs of wilt.
With repeat aerations over time, your lawn will show enhanced heat and
drought stress tolerance.
Remember, most lawns benefit from annual
aeration. And while you shouldn't expect miracles, especially with poor
soil, lawns that receive this care will be healthier, more vigorous,
easier to maintain, and have fewer pest problems.
Technical credit: This brochure was
written by Dr. Robert Shearman, horticulture professor at the University
of Nebraska, Lincoln NE.