What's wrong with the lawn?
The first step
is to determine what is wrong with the lawn. Lawns go downhill for
many reasons, including:
soil pH (acidity/alkalinity) too high or too low
lack of or improper fertilization
lack of or improper irrigation
too much shade
competition from tree roots
turfgrass species not
adapted to the site
heavy thatch layer
insect or disease problems
the weeds are winning
A good place to
start is with a soil test. Inadequate (or excessive) fertilization
can limit turf growth. A soil test will tell you what type of
fertilization program is required. It will also tell you what you
have to do to get your soil pH into the optimum range of 6.5 to 7.0
that most turfgrasses prefer. Soil test kits are available from your
local Penn State Cooperative Extension office.
Proper mowing methods
Mowing practices greatly determine the quality of turfgrass. If you allow
your lawn to grow too long, then cut it short, you are not doing it
any favors. Most species of turfgrass should be cut at a height of 2
to 3 inches. The longer the grass, the more extensive its root
If you do not
water your lawn, drought years past and present have probably taken
their toll. Deep infrequent watering during hot, dry weather is
important to maintain a healthy lawn. Deep watering encourages the
turf to develop a deeper, more extensive root system. Conversely,
frequent shallow watering encourages a shallow root system that is
stressed during droughts.
Use a sprinkler
or an irrigation system to apply 1 to 2 inches of water weekly to
your lawn if we are not receiving any rain. This is best applied in
one long, deep soaking session. Our clay soils can absorb only about
1/2 inch of water an hour, so it should take two hours of watering
to apply an inch of water.
To measure how
long to run your sprinkler or irrigation system, take a
flat-bottomed container such as a coffee can and mark off half-inch
increments. Place the can where it will be hit by the water, and
time how long it takes to gather a half-inch of water. (You may want
to place several cans because your sprinkler may not distribute the
water evenly.) Then run your sprinkler twice as long.
You may need to
apply water even more slowly to steep slopes to avoid wasting it to
runoff. It is best to water in the morning. If you water during the
heat of the day, too much water is lost to evaporation; if you water
at night, the grass stays wet too long and may be more likely to
have disease problems.
species prefer full sun. If your lawn is heavily shaded, you may
need to remove or limb up some of the trees to allow more sun to
penetrate. You may also wish to overseed with fine fescues such as
creeping red fescue, hard fescue or Chewings fescue. They are the
most shade-tolerant species of turfgrass adapted to our climate. The
newer turf-type tall fescues perform reasonably well in shade, too.
compete with turf for water and nutrients. Turf grown under such
conditions should be watered more frequently and fertilized at a
heavier rate than turf that does not have such competition. Often,
shade-tolerant groundcovers such as barrenwort (Epimedium
spp.), ferns, Allegheny foamflower (Tiarella cordifolia),
pachysandra or creeping myrtle (Vinca minor) are better than
grass in such a situation.
frequently have thick thatch layers. Thatch is a tangled mat of
organic matter that accumulates between the soil surface and the
grass. Just as we slough off dead skin cells that are replaced by
new ones, turfgrass plants slough off dead roots and stems. When
these accumulate faster than they break down, a thick thatch layer
can build up. How quickly thatch accumulates depends on:
The variety of grass in your lawn. Kentucky
bluegrass and creeping red fescue spread by underground stems
(rhizomes) and tend to build up thatch faster than bunch-type
grasses such as perennial ryegrass, turf-type tall fescue and
Chewings or hard fescue.
The pH of your soil. Soil-dwelling microbes that
break thatch down are inactive when the pH falls below 6.5.
Mowing practices. Letting your grass grow long,
then cutting it short will create more dead roots and stems that
end up adding to the thatch layer. Also, leaving very long grass
clippings on the lawn on a regular basis will cause thatch to
build up. However, a properly used mulching mower does not
contribute to the thatch layer because it cuts the clippings
into very fine pieces that break down quickly.
Over-fertilization. Too much fertilizer causes
the grass to grow more quickly than normal and also speeds up
the process of sloughing off dead stems and roots, which
contribute to thatch build-up.
Compacted soil prevents the roots from
penetrating deeply. Shallow roots dry out and die faster and add
to your thatch woes.
A little bit of
thatch, say a half-inch or so, is actually helpful. It acts like a
mulch to conserve water, moderate soil temperature and shade out
germinating weed seeds.
thatch layer becomes a breeding ground for disease and insect
problems and interferes with treating root feeding insect problems,
such as white grubs.
Up to 2 inches
of thatch can be removed with a power dethatcher, often available at
tool rental shops. Or hire a lawn service to do it.
Run the power
dethatcher in one direction, then again in the perpendicular
direction. It is important that the tines get through the grass and
thatch layer and down into the soil. A properly dethatched lawn
should make you want to cry because it is so badly torn up.
Overseeding will help it recover.
should be done in fall only so that your lawn has ample time to
recover. There are limitations to what dethatching can accomplish.
If you have a thatch layer more than 2 inches thick, consider
starting a new lawn.
I have had better success planting grass in the fall than in the
spring. Is there any validity to that, or should it not matter when
I seed my lawn?
A: Fall is the
BEST time to establish a new lawn for many reasons. First of all,
soil temperatures are warm, which creates a favorable environment
for seed germination, as well as root growth and establishment. Root
growth continues until soil temperature falls below 40 degrees.
temperatures tend to be cooler in fall, which is much less stressful
for tender grass seedlings. The cool-season grasses typically grown
in our climate perform best in the cooler weather of spring and
fall. They generally stay green through much of the winter but will
go dormant during hot, dry summer weather unless provided with
lawns have fall, winter and spring to become established before
facing the stress of summer heat and drought. If you start a new
lawn in the spring, you must be prepared to water most of the summer
for it to become well established.
is much less weed pressure on a fall lawn seedling than there is in
the spring. Weed seeds are genetically programmed to germinate when
they have the best chance to survive and perpetuate the species. For
the vast majority of weeds, that is spring.
often see commercial landscape companies seeding new lawns late into
the fall, it is best to have your seeding done by Oct. 15th in