By Sharon Omahen
University of Georgia
The abundance of rain in Georgia is, for the most part, a
blessing. Your turf grass may not agree.
“We’ve had one of the wettest Mays and Junes on record,” said
Clint Waltz, a turf specialist with the University of Georgia
College of Agricultural and Environmental Sciences.
Compacted soil
“Too much water combined with traffic can cause the soil to
become compacted. And when it does dry out, there isn’t enough
room for oxygen to get to the plant’s roots,” Waltz said. “Two of
turf grasses’ major needs are water and air. Too much of one can
affect the other.”
So how to do know if your soil is compacted?
“You’ll see wear patterns on the turf once it dries out,” he
said. “Or there will be thin areas and spots that are extremely
hard and too tough to penetrate.”
To solve the problem, Waltz suggests renting an aerator or
hiring
a service. An aerator is a device that punches holes in the soil.
These holes are typically 3 to 6 inches deep and will allow for
much-needed air flow.
Run the aerator over the affected area two to three times in
different directions, he said.
“Not all areas of the lawn need aerification,” said Waltz.
“Only
treat the area that needs it. And make sure you do this while the
grass is actively growing.”
Some aerators actually pull out cores of turf and soil. Either
dispose of these or work them back into your lawn, he said.
If your soil is clay, he recommends leaving the new air holes
unfilled and letting them fill in naturally. If your soil is
sandy, he said, you can incorporate an organic matter as an
amendment to improve its nutrient- and water-holding
capacity.
Waltz said centipede and St. Augustine grasses don’t respond
to
aerification as well as Bermuda and zoysia.
Disease pressure
Besides compacting soils, the recent rains have increased turf
disease pressure.
“By far the biggest turf disease problem caused by the rain
has
been brown patch,” said Mila Pearce, a UGA integrated pest
management specialist. Pearce works closely with UGA Extension
Service county agents to identify submitted disease samples and
make recommendations for homeowners.
“Brown patch is caused by a fungus that primarily gets in the
root and crown,” she said. “It causes large brown patches that
will slowly expand if they aren’t treated.”
Pearce said homeowners often make brown patch worse by acting
on
their first reaction. “Their instinct is to throw nitrogen to it
to green it up,” she said. “This is the absolute worst thing to
do and it makes it 10 times worse.”
If you have to fertilize, Pearce said, select a low-nitrogen
type. Brown patch is typically seen on zoysia and Bermuda
grasses.
Homeowners with St. Augustine grass are reporting a different
disease problem.
“We’re seeing a lot of gray leaf spot in St. Augustine grass,
which
is a direct result of all this wet weather,” Pearce said. “It
leaves gray, water-soaked lesions and eventually causes drying
and dieback.”
One dose won’t do it
To control these diseases, you have to develop a schedule.
“Homeowners think they can spray one time and be done,” Pearce
said. “One spraying will only reduce disease. It’s not uncommon
to have to keep a spraying schedule of every 10 to 14 days.”
Pearce said aerating the soil and reducing thick thatch areas
will help prevent diseases. To control them, she recommends
selecting a chemical treatment such as Immunox, Terraclor or
Cleary’s 3336.
“One thing you can’t control is Mother Nature. So as long as
it
rains, you’ll just have to be prepared to make continual sprays,”
Pearce said. “Spraying is not going to remove it. It’s just going
to reduce it and keep it from spreading.”
