|
|
 |
|
Creating and maintaining quality turfgrass involves more than irrigation,
fertilization, and pesticide applications. A dense, healthy turf demands
proper mowing techniques, occasional dethatching, and aerification in addition
to fertilization and pest control. Knowing when and how to use these cultural
practices will help enable one to have a dense, vigorous turf.
Choosing a Grass
A beautiful lawn begins with choosing a type of grass that is suitable for the climate. Pacific Northwest, the best choice
is perennial ryegrass for full sun and a mixture of perennial ryegrass and fescue for part-shade.
One drawback to perennial ryegrass is that it has to be watered enough to keep it green during the
growing season. Otherwise, it thins out until the lawn is dense clumps with bare spots in between.
Perennial ryegrass will not spread to fill in the bare spots like most other grasses so bare spots
need to be reseeded. A lawn that won't be watered should be at least half fescue. Fescue is much
more drought tolerant and will come back quickly when rainfall resumes.
Mowing
A new lawn should be mowed as soon as it reaches regular mowing height. The mower should be sharp
because a dull blade might rip young seedlings out of the soil. Then regular mowing, usually weekly,
during the growing season is the main task in maintaining a lawn. It is a good idea to vary the
mowing pattern. I mow a clockwise spiral one week, then north-south the next week,
then a counterclockwise spiral, then east-west. This prevents ruts from running the mower wheels in the same track each time.
Edging
Edging the lawn along sidewalks and driveways is optional but it gives the lawn a professionally
manicured look. An electric or gasoline powered edger will be a small investment to give your lawn a finished and
kept look.
Watering
Most grasses in most of the country need the equivalent of an inch of rainfall each week.
More is needed during hot weather or in arid climates. If the grass has a dull appearance
or it fails to stand back up after being stepped on, it is dry and needs watering immediately.
Clay or sandy soils usually need a half-inch of water two or three times a week. If
the soil is loose and has lots of organic matter to hold water, an inch could be applied
once a week. Watering every day prevents the grass from growing a deep root system and also
causes tree roots to grow on the surface of the soil.
A handy way to measure how much water is applied is to scatter some tuna or pet food
cans in different parts of the lawn. Whether hose end sprinklers or underground
sprinklers are used, water should be applied evenly and slow enough that it soaks in
and doesn't run off. The best time to water is right after sunrise
when it is cool so less water evaporates before it hits the ground.
Fertilizing
Fertilizing a lawn regularly will give it healthy green color as well as help prevent
disease and weed problems. If a lawn is well fed and growing rapidly, disease spots on
the grass blades are mowed off before they become visible.
A thick lawn will prevent weeds from getting started.
Insect Control
Lawns in the Northwest are occasionally attacked by chinch bugs, bill bugs, and grubs
but the most common insect is the European cranefly which looks like a giant mosquito.
Cranefly eggs hatch into larvae in the fall. The larvae feed on grass roots from September
through May then the larvae pupates and emerge as adults in late summer. There can be as
many as thirteen larvae per square foot without causing any visible damage. Greater numbers
cause dead patches of grass, which can be pulled right out of the ground because there are no
roots. The easiest way to check for soil insects is to dig up a plug of lawn on the edge of a
dead spot, put it in a plastic bag and see what crawls out of the soil. Almost all lawn insects
can be controlled by applying beneficial nematodes which are microscopic worms which prey on many soil insects
Weed Control
Weeds are either broadleaf, such as dandelions and chickweed, or grassy,
such as crabgrass and annual bluegrass. Broadleaf weeds are easiest to control
since many lawn weed killers will kill broadleaf weeds without harming grass.
The active ingredient in most broadleaf weed killers is either 2,4-D or Trimec.
Weed and feed fertilizers have to be applied evenly over the entire lawn even
where there are no weeds. I prefer to use a plain fertilizer,
then spot apply liquid weed killer only on the weeds.
Grassy weeds are harder to control since most grass killers will kill
lawn grasses as well as weedy grasses. A grassy weed preventer, such as
Halts or Team, can be applied in the spring when the first dandelion blooms
to prevent crabgrass and around Labor Day to prevent annual bluegrass.
Coarse grasses which grow taller than the lawn grasses can be controlled
by using a paint brush to apply Roundup to the taller tips.
The best weed control is a thick healthy lawn that crowds out weeds.
Weeds are a sign that the lawn is stressed, usually by poor soil,
lack of regular watering, lack of fertilizer or mowing too short.
I once visited a natural prairie area on the edge of a school yard.
The school yard was so full of dandelions that they overlapped but
there were no more than a handful of dandelions in the entire prairie.
The dandelions ended right at the edge of the mowed area. Low mowing
allows more sunlight to reach the soil which encourages weed seed growth
while a higher mowing height causes the soil to be in deeper shade, which discourages weed seed growth.
Another common weed is moss. It is almost guaranteed to grow during the
rainy season anywhere there is shade. By spring, moss will have killed
out quite a bit of grass. It is better to use moss killer in early winter before moss smothers the grass.
Almost all moss killers for lawns contain iron sulphate. It will stain
concrete so sidewalks, driveways and patios should be hosed off immediately after moss killer is applied.
Aerating
Soils that get walked on or trampled will pack
down until air can't penetrate into the soil to
keep the roots healthy. If a lawn has patches where
grass won't grow in spite of fertilizing and watering,
it needs to be aerated. An aerator punches holes in the
lawn ever few inches to allow air and water to penetrate
into the soil faster and deeper. The easiest and best way to
deal with the cores that are left on the surface is to mow over
them and scatter the soil onto the lawn surface. This fresh soil
brings up microbes which help break down thatch.
The frequency of aerating depends on the soil and the amount of
traffic on the lawn. Athletic fields are aerated every few months.
A yard on clay soil with active kids may need aerating every year.
On the other hand, a yard with rich soil and lots of earthworms may never need aerating.
Thatching
Thatch is a layer of dead stems and roots that can build up on
the surface of the soil. If you dig into the lawn with your finger,
it is fairly easy to tell the difference between the soft, light thatch
and the hard, heavy soil. A quarter inch thick layer of thatch is of no
concern. If thatch is an inch thick, disease problems are almost sure to
occur. Also, a thick layer of thatch will make a lawn require more water and fertilizer to keep the lawn green.
There are several products available to reduce thatch. They contain
microbes that will break down thatch quicker. If the thatch is an
inch thick, then it is better to use a thatcher, also called a power
rake, to quickly remove thatch before diseases develop. Before using
a thatcher, mow the grass as low as possible to reduce the damage to
the grass. Set the depth on the thatcher so the teeth just reach the
mineral soil. Then run the thatcher over the lawn twice, going
east-west one time and north-south the other. The loosened thatch
then needs to be raked up and hauled away. Do not bother adding it
to the compost pile since it is tough roots and stems which are very slow to break down.
Thatching usually leaves bare patches so it is a good idea to spread
starter fertilizer and grass seed after thatching so the bare patches
fill in before weeds get started. Therefore, thatching should be done from mid-April to mid-October.
|
Providing your dream outdoor living environment.
|
|
Top of Page
|
|
