Problem: Dog spots on grass
Symptoms: Dog spots are round patches
about 4 to 8 in. in diameter with dead
grass in the middle, encircled by dark
green grass. They’re most apparent in the
early spring when dormant grass first
begins to turn green again.
Cause: Dog urine contains high concentrations
of acids, salts and nitrogen,
which burn (dry out) the grass roots and
kill them. As rain washes the area, the
urine is diluted and the nitrogen spreads,
causing the grass
surrounding the spot
to grow faster and
Remedy: You have
to replant your grass;
it won't come back
on its own. But first you have to dilute or remove the
caustic urine from the soil (Photo 1). Thoroughly soak
the area with lots of water. Let the hose run for at least
three minutes. Then you can start the replanting process
(Photo 2). Add a half inch of new soil to help absorb any remaining urine
(Photo 3). Then you can spread new seed, as we show, or use a commercial
yard patch mixture (available at most nurseries or home centers) or even sod.
In any case, the secret of good germination is keeping the seed moist. And
keep the area moist until the new grass is about 3 in. high.
seed, moisten the
soil daily and keep
it damp—but don't
soak it. Overwatering
Recovery time: Four to six weeks.
Symptoms: If your grass feels soft and
spongy when you walk on it, your lawn
may have a thatch buildup. Thatch is a
fibrous mat of dead stalks and roots that
settles between the lawn's green leaves
and the soil (photo above). When this mat
becomes greater than 3/4 in. thick, it can
cause your lawn to suffer from heat and
drought. Affected lawns will rapidly wilt
and turn blue-green, indicating they're
hot and dry.
Cause: Cutting off too much at each
mowing (letting the grass get too long)
and cutting too low. Both will produce
more dead grass tissue than microbes and
earthworms can recycle. Thatch can
develop in any soil but is most often associated
with high clay content. Other causes
are overfertilization and frequent, light
watering, which encourage a shallow root
Remedy: Slice open a section of your
lawn (Photo 1). If your grass shows 3/4
in. or more of thatch, it's time to rent an
aerator. An aerator is
a heavy machine that opens the soil by
pulling up finger-size soil cores. The lawn
will absorb more oxygen and water, which
will encourage healthy microbe growth
and give worms wiggle room.
Aerate in the spring or fall when the
grass is growing but the weather is not too
hot to stress the plants (Photo 2). If the
machine isn't pulling plugs, your lawn
may be too dry. To avoid this problem,
water thoroughly the day before you aerate.
You can also rake in topsoil (Photo 3)
to increase the healthy microorganisms
that aid thatch's natural decomposition.
Topsoil is available at any garden center.
Recovery time: You can expect the thatch
layer to decrease by about 1/4 in. per year,
about the same rate at which it forms.
Renting a Lawn Aerator
If your goal is to have one of the
nicest lawns on the block, you
can go a long way toward achieving
it with annual aeration.
When a lawn lacks sufficient
air (a “compacted” condition), it
grows slowly and becomes vulnerable
to disease, insects and
heat damage. The soil will become
impermeable and shed
water instead of absorbing it.
Gas-powered aerators are available
at most tool rental stores.
They're slow-moving but powerful
machines, so ask the clerk for
handling directions. An aerator
weighs about 200 lbs., so be prepared
for some heavy lifting or
ask your rental store for a ramp
to get it into a truck bed or van.
Cool-season grasses should be
aerated in the late summer or
early fall. Spring is best for
warm-season types. (If you're not
sure what type you have, take a
sample to an expert at a local
Resist the temptation to remove
the thatch with a rented
power rake. Power raking is less
effective than aerating because
it typically removes less than 15
percent of thatch and may damage
the healthy grass as well.
Problem: Fairy Ring
Symptoms: Fairy rings are circles approximately
3 to 8 ft. wide that consist of a
dark green and fast-growing area of grass
surrounding an inner area of partially
dead or thin grass. Some rings also produce
Cause: Fairy rings are caused by fungi
that live in the soil. As the fungi feed on
organic matter, they release nitrogen,
causing the grass to turn dark green. As
the colony grows, it disturbs the flow of
needed water to the turf roots, creating
thin or dead spots. Fairy rings often begin
with the decomposition of organic matter,
such as an old tree stump buried under
Remedy: By bringing up the color in the
rest of your lawn with a nitrogen fertilizer,
you can mask much of the overgreening
of the fairy ring (Photo 1). Hand-aerating
the ring will break up the fungus and
allow the flow of water and other nutrients
to the grass roots (Photo 2).
Recovery time: Generally fairy rings can
be masked with the application of fertilizer,
with results in 10 to 14 days. The grass
within the ring will thicken up with aeration
in about two to three weeks.
Symptoms: Grub-chewed turf has patchy areas that wilt and die. You can easily pull
up the affected turf if you tug on it.
Another indicator of grubs may be
increased raccoon, bird or mole activity.
They like to dig up and eat the grubs at
night. While this may sound good, the
moles will kill the grass as they forage for
Cause: Lawn grubs are the larval stage of
moths and beetles. The grubs eat the roots
of grass, setting them up for death by
Remedy: Be vigilant. Are beetles swarming
around your porch light? In the next
month, keep an eye out for patches of
grass that wilt or are blue-green on hot
days. They may be larvae infested. Turn
over some turf (Photo 1). If you count six
to 10 grubs (white wormlike larvae with
black heads) under a 1-ft.-square area of
sod, consider using a grub insecticide
(available at home centers and nurseries).
Or talk to a professional (search “Grass Service”
online) about treating your
yard. They will be familiar with the grub
problems in your region and the most
suitable treatment methods.
If you spot the grubs but your count is
lower than six per square foot, baby your
lawn to strengthen its natural defenses.
Mow on higher blade settings and water
thoroughly but infrequently to encourage
the grass to grow new, deep roots. Do not
cut off more than one-third of the grass
height at each mowing, to avoid stressing
Back to Top
Symptoms: Shaded grass will
look thin and patchy. Some types
of grass actually produce wider
blades as the plant attempts to
catch more rays. But they also
produce far fewer blades, lending
a spindly appearance to the lawn.
The cold truth is, if your lawn
gets less than six to eight hours
of sun daily, you are unlikely to
sustain lush grass.
Cause: Trees, buildings and
Remedy:There are no good
remedies. You can increase the
sunlight as much as possible by trimming trees and
shrubs. Also try starting areas in shade with sod instead
of seed. The sod will adjust to the lower level of light.
Although all seed varieties have their shade limitations,
try overseeding your thin area with a shady grass mix.
Or throw in the towel, grab your trowel and plant a
shade-tolerant ground cover. Many will thrive where
your turf withered. Lamium (dead nettle) and ajuga
(bugleweed) collaborate nicely in providing lovely
blooms and an enthusiastic, but not invasive, carpet.
This pair fares well, with a hearty tolerance spanning
zones 3 to 8, and can be planted
right up to your grass. They are
fairly low growers and won't get
more than a few nicks from a
Also, mulching between the
ground cover plants will help
retain moisture. This is especially
wise if your new “shade garden”
is on a slope; mulch will
help prevent your fledging plants
from washing out in a hard rain.
Recovery time: The plants and
mulch will immediately boost
the appearance of an area that
was once thin grass. It'll take a
couple of seasons for the ground
cover to become established and
blanket the area.
Call your local
utility provider or
to mark your
before you dig.