You don't have to slave over your lawn to keep it healthy
If you’re an average
homeowner (and of
course you’re not!), you
spend 3.8 hours a week
on yard work and mow
your lawn 30 times a year.
And while you may not
realize it, your lawn pays
you back for all this hard
work. It serves as a giant
air conditioner to help
cool your home. It releases
a tremendous amount
of oxygen and captures
tons of dirt and dust to
help keep you and your
family healthy. It gives
you a place to play croquet.
And the healthier
your lawn is, the better it
keeps up its end of the
The good news is, you
don’t have to slave over
your lawn to keep it
healthy. In fact, to a
great extent, it’s not
the amount of work
you put into your
lawn—it’s when and
how you do it. The following
are essential for a healthy
lawn. We focus on northern
or cool-climate grasses
like bluegrass and fescue,
but most of the information
applies to warm-climate
grasses like zoysia
and Bermuda grass, too.
Tip 1: Adjust your cutting height to the time of year (and use a sharp blade)
For cool-climate grasses, use a 1-1/2 in. cutting height for the first mowing of the
year to remove dead grass and allow more sunlight to reach the crowns of the
grass plants. Raise the blade during the heat of summer to 2 or more inches. Then
lower the blade back to 1-1/2 in. for the last cutting of the year. For warm-climate
grasses, these heights will be about 1/2 in. lower.
When adjusting your blade height, measure from a hard surface to the bottom
of the mower deck, then add 1/4 in. (most blades sit 1/4 in. above the bottom of
Cut your grass using a sharp blade (illustration below). A dull one tears grass rather
than cutting it cleanly. Damaged grass turns yellow, requires more water and
nutrients to recover, and is more susceptible to disease. Sharpening and balancing
a blade three times a year is usually enough to maintain a good cutting edge—
unless you hit lots of rocks.
A well-maintained blade and a poorly maintained blade
Use a Sharp Mower Blade
A well-maintained (sharp and balanced) blade cuts grass cleanly
A poorly maintained (dull) blade shreds grass, leaving it more
susceptible to disease and in need of more
nutrients to repair the damage. An unbalanced
blade compounds the problem (and
can damage your lawn mower’s bearings).
Tip 2: A few good soakings are better than lots of light sprinklings (but not in the evening)
Deep watering helps develop deep
roots that tap into subsurface water
supplies (illustration below). Light sprinklings
wet only the grass and surface
of the soil; this encourages shallow
root growth and increases the need
for more frequent watering. As a
general rule, lawns require 1 to 2 in.
of water per week (from you or
Mother Nature), applied at three- or
four-day intervals. But this varies
drastically depending on the temperature,
type of grass and soil conditions.
Lawns in sandy soils may need
twice as much water, since they drain
quickly. Lawns in slow-draining clay
soils may need only half as much.
When your lawn loses its bounce
or resiliency, or when it wilts,
exposing the dull green bottoms of
the blades, it needs water. As a general
game plan, water until the soil is
moist 4 to 5 in. down, then wait to
water again until the top 1 or 2 in. of
soil dries out. To find out how much
water your sprinkler delivers, set
out a cake pan, turn on your sprinkler,
then time how long it takes for
the water to reach a depth of 1 in.
The best time of day to water is
early morning. Water pressure is
high, less water is lost to evaporation
and your lawn has plenty of
time to dry out before nightfall.
Lawns that remain wet overnight
are more susceptible to disease
caused by moisture-loving mold
and other fungi.
A properly watered lawn and an
improperly watered lawn
Good Watering Pays Off
Properly watered lawns receive an initial soaking 4 to 5 in. deep,
and are then watered when the top 1 to 2 in. of soil dries out,
develop deep, healthy grass roots. This usually means applying
1 to 2 in. of water per week at three- or four-day intervals.
An impact sprinkler delivers water quickly, with less
“hang time” for evaporation; a 3/4-in. hose delivers much
more water volume than its 1/2-in. cousin.
Improperly watered lawns receive short daily waterings that promote shallow
root growth. Oscillating sprinklers
toss water in a high arc, so
more evaporates before reaching the
soil. Watering late in the evening
when your lawn doesn’t have time
to dry out allows disease-carrying
fungi and mold to grow.
Tip 3: Mow only the top one-third of the grass blade (and don't rake up the clippings)
The top one-third of a blade of grass is thin and
“leafy,” decomposes quickly when cut and can contribute
up to one-third of the nitrogen your lawn
needs (illustration below). While it’s decomposing, this light
layer of clippings also helps slow water evaporation
and keeps weeds from germinating.
But the bottom two-thirds of a blade of grass is
tough, “stemmy” and slow to decompose. It contributes
to thatch, which—when thick
enough—prevents sunlight, air, water
and nutrients from reaching the soil.
Cutting more than the top third also
shocks grass roots and exposes stems, which tend to
burn in direct sunlight.
This means if 2 in. is your target grass length, cut it
when it reaches 3 in. Since grass grows at different
rates at different times of the year, “every Saturday”
isn’t necessarily the best time to mow. Sometimes you
need to mow it more; other times, less. The ideal
length for cool-climate grasses is 3 to 4 in.; for warm-climate,
1 to 2 in.
Mow when the grass is dry and avoid mowing
in the heat of the day when you’re more likely to
stress the grass—and yourself.
The correct mowing height and the
wrong mowing height.
Set the Correct Mowing Height
For the correct mowing height,
cut off no more than
one-third of the grass’s
height at a time. The upper
leafy grass clippings easily
decompose, adding nitrogen
to your soil.
Don’t cut off more than one-third of the
overall height of the grass or you’ll not only
shock the plant but also leave
thick, stemmy clippings that are
slow to decompose, and therefore
contribute to thatch.
Tip 4: Timing is everything when it comes to fertilizers and weed killers
When applying weed killers and fertilizers, you must
take into account such variables as geographic location,
grass type, weed type and soil conditions. But here are a
few general guidelines:
- The best defense against weeds is a thick, healthy
lawn (illustration below) that doesn’t provide weed seeds adequate
sunlight or open space to germinate.
- Attack weeds in the early spring and summer before
they have a chance to develop deep root systems, go to
seed or reproduce.
- Different weeds need to be dealt with using different
chemicals and methods. It’s best to eradicate
grassy weeds like crabgrass with pre-emergent weed
killers, which destroy germinating plants just as
they sprout. Broadleaf weeds need to be
attacked while they’re young and
actively growing; spraying the leaves
of individual plants or patches of plants is most effective.
Dandelion killers work by literally growing the
plant to death.
- Fertilize in early spring to jump-start root development.
Fall feedings help repair summer damage and
spur the root growth that goes on for several weeks even
after the top growth stops; this helps grass survive the
winter. Light feedings in between help maintain healthy
- Read the package. Some chemicals work only in the
presence of moisture; other chemicals are rendered useless
by water. Heed the safety warnings too.
The best resource for identifying and troubleshooting
weeds is a nursery or garden center familiar with local
A healthy lawn and a sick lawn
Get After Weeds Early—A Thick Lawn Will Crowd Out Most Weeds Later
A healthy lawn that’s full and hard to penetrate is your best defense against weeds. Preemergent herbicides knockout crabgrass and other grassy weeds before they have a chance to get established. Broadleaf weeds should be eradicated while plants are young by spraying herbicides directly on the leaves.
A sick, spotty lawn leaves lots of open space for weeds to take root and grow.
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Tip 5: Aerate your lawn to help it "breathe"
Grass roots need oxygen as well as water and
nutrients. Aerating—the process of removing
small plugs of soil (see illustration)—produces
multiple benefits. It improves air-to-soil
interaction. It allows water and fertilizer to
penetrate the soil deeper and easier. It
reduces soil compaction and opens space for
roots to grow. It removes some thatch and
stimulates the breakdown of the
remaining thatch. The best tool for
this task is a gas-powered aerator,
available at most rental centers.
Again, timing is critical. You can
aerate in the spring. But fall—after
the kids are through trampling the
grass and there are fewer weed seeds
to set up home in the open spaces—is the best time to aerate. It’s usually
best to aerate first, then apply any
weed killers so the open holes are
protected against weeds.
A Well-Aerated Lawn
A well-aerated lawn provides space for
grass roots to grow, reproduce and take in more
oxygen, moisture and nutrients. The plugs,
composed of thatch and soil, quickly break apart
A Compacted Lawn
The root of a compacted lawn have difficulty absorbing
air, water and nutrients.