Crabgrass
Control
Wisconsin lawns are primarily made
up of Kentucky bluegrass, perennial ryegrass and red fescue.
These are what are known as perennial cool season grasses.
Crabgrass can become a weed in our bluegrass lawns. Crabgrass is
a warm season annual grass which grows best in the heat of
midsummer when desirable lawn grasses are often semi-dormant and
offer little or no competition.
Crabgrass overwinters as seed,
comes up about mid-May or later when soils are 55 b or warmer,
and is killed by the first hard frost in fall. Crabgrass grows
best in full sun. It does not grow in shady places. Crabgrass
can be controlled in a number of ways, but the best defense
against crabgrass is a thick vigorously growing lawn that is
mowed no closer than 2 ½ inches. Fertilize the lawn in late
summer or fall and again in spring to develop a dense, healthy
stand of grass. Fertilized bluegrass does not go into midsummer
dormancy as soon as unfertilized bluegrass.
Set the mower to cut at 3 inches.
The taller height of cut produces more shade at the soil surface
and inhibits crabgrass development.
If you wish to apply a chemical
control, apply a preemergence crabgrass herbicide in April or
early May. You can usually buy these herbicides in granular form
either alone or mixed with fertilizer. Spread the product with a
fertilizer spreader to ensure even distribution. The herbicides
kill germinating crabgrass seedlings. One application protects
for the entire growing season. Timing of the application is
important. If you apply the product too early, it may become
diluted by heavy spring rains before it has a chance to work.
If you apply a preemergence
herbicide after crabgrass has germinated, it will not be
effective. You must apply it before the seeds germinate. Again,
the best time to apply the preemergent herbicide is between mid
April and early May.
Postemergence crabgrass herbicides
are now available. These are products that are applied after the
crabgrass seed has sprouted. The herbicide gives excellent
crabgrass control with one application. This product should be
applied when crabgrass is in the 3 to 4 leaf stage of
development.
From: Infosource |
