These articles are written to apply to the northeastern
corner of Illinois. Problems and timing may not apply outside of this
area. |
Think Ahead to Crabgrass Control in 2000
February 24, 2000
Crabgrass was a major lawn weed last season, as conditions were ideal
for development. If you had crabgrass problems last year, you probably
are concerned about stopping it in 2000. We have plenty of time to act,
but here's an overview of your options to keep crabgrass out of your
lawn.
Crabgrass is a warm-season annual grass. No matter how many crabgrass
plants appeared in your lawn last year, they are all dead. To have crabgrass
here in 2000, seeds in the soil must germinate into new plants. This will
not occur until soil temperatures get close to 60 degrees and stay there
for several consecutive days, which most likely is not until late May
or early June. So remember, you have plenty of time.
Sound lawn management practices help prevent crabgrass from becoming
a problem. Mowing height has a major impact on crabgrass. Mow between
2 1/2 and 3 inches and there will be fewer crabgrass plants in your lawn.
Also avoid frequent watering, especially frequent light sprinklings.
Crabgrass often invades bare soil in lawn areas that are disturbed in
late spring or early summer. If possible, hold off lawn establishment
or renovation work until late summer to avoid potential crabgrass problems.
The same holds true for destructive practices such as dethatching.
Several preemergence herbicides (weed killers) are available to use in
spring for
crabgrass control. These need to be applied to the lawn before crabgrass
germinates. Late April into early May is the suggested time for applying
preemergence crabgrass herbicide in our area. If April is unusually warm,
apply by late April, otherwise early May is not too late.
Most preemergence crabgrass herbicides are found as a combination with
lawn fertilizer at garden supply stores, so the crabgrass prevention and
spring fertilization can be done at the same time. Follow the rates given
on the bag. One of the management problems associated with preemergence herbicides
is seeding or overseeding practices. With the exception of a herbicide
called siduron, all preemergence annual grass weed killers will also damage
germinating desirable grass seed. Siduron may be found as lawn starter
fertilizer with crabgrass preventer. |