Homeowners often don’t realize how much
soil compaction
affects the overall health of their lawns. Insects, diseases,
improper
watering and a lack of fertilizer are often blamed for problems in
home
lawns, when the real culprit is compaction. The problem starts when
particles in the top 4 inches of the soil are compressed, reducing
the
pore space which impedes the movement of air, water and nutrients to
the
grass roots. This, in turn, stresses the grass plants, making them
less
able to compete with weeds and slow to recuperate from injury. In
time a
compacted lawn needs renovation. Golf course managers commonly
aerate
fairways and greens with dramatic results.
If soil is compacted, the solution is simple - aerify. The
practice of physically removing cores of soil and leaving holes or
cavities in the lawn is defined as core aeration or aerification.
Aerifying a lawn benefits compacted soil in the following ways:
1)
Loosens compacted soil and increases the availability of water and
nutrients.
2) Enhances oxygen levels in the soil, stimulating root growth and
enhancing the activity of thatch-decomposing organisms.
3) While
removing cores of soil, the spoons or tines also sever roots,
rhizomes
and stolons. Grass plants are stimulated to produce new shoots and
roots
which "fill up" the holes in the lawn and increase the density of
the
turf.
4) Reduces water runoff.
5) Increases the lawn’s drought
tolerance and improves its overall health.
Warm-season grasses such as zoysia, centipede, carpetgrass, St.
Augustine and bermudagrass, are best aerified in late spring and
summer
when they are actively growing. Choose a day when the soil is
moderately
moist, which makes the soil easier to penetrate. Avoid aerifying a
wet
soil because it is messy and leads to further compaction of the
soil.
Aerification is not expensive. The simplest and cheapest way to
aerify a small lawn is with a spading fork. Push the tines into the
soil
as far as you can (at least 4 inches) and rock the fork back and
forth
to enlarge the holes. This movement will loosen up the soil and make
room for new grass roots. The only limitation to using a spading
fork is
that at the same time that you are making a hole you are also
forcing
soil particles around the hole closer together, causing more
compaction.
Aerifying larger lawns requires a power-driven core aerator or
aerifier, which can be rented at area rental centers. The working
parts
of these machines are spoon-shaped tines or hollow tubes. As the
tubes
are driven into the lawn, cores of soil are removed from the ground
and
strewn across the lawn. Both types of tines work equally well, but
the
hollow tine makes a somewhat cleaner hole than the spoon type and
brings
up less soil.
Most of the lawns in this area would benefit from soil aeration
at least once per season. Penetration depth depends on soil type,
soil
moisture, tine diameter and the weight and power of the aerifier.
Soil
cores should be left on the lawn to be broken up by rainfall and
traffic. If their appearance bothers you, you can speed up their
disappearance by raking them into the grass. For best results, go
over
the lawn twice, once in one direction, then in a perpendicular
direction.
Don’t forget to send your garden questions
to Plant Answers at
9020 FM 1484, Conroe TX 77303 or e-mail me at t-leroy@tamu.edu .
Educational programs of Texas Cooperative Extension are open to
all citizens without regard to race, color, sex, disability, age or
national origin.
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