•
Poor preparation of the site at lawn installation
•
Neglect or incorrect turfgrass management
Proper
mowing, watering and fertilizing will correct most
if not all weed incidences.
There
are two groups of chemicals that will assist you in
your lawn care and battle with weeds:
Post-Emergents
– just as the name implies, Post Emergents
are chemicals that are used to eliminate weeds AFTER
or post germination. 2-4,D and Trimec are two common
and readily available products that are post emergents.
Pre-Emergents
– again as the name implies, Pre-Emergents are
chemicals that are used to eliminate weeds BEFORE
they germinate and become visible. Dacthal and Ronstar
are two common pre-emergent products.
There
are also two major groups or classifications of Weeds:
Grassy
Weeds - The appearance of this weed resembles
grasses in that they are stout and smooth stemmed,
are sheathed in long slim and often hairy leaves.
Germination of these weeds occurs when day time
temperatures exceed 80 degrees. In the south this
can occur as early as March and in the North around
June. Examples of this type of weed include Barnyard
grass, Crabgrass, Goosegrass and Dallisgrass.
Broadleaf
Weeds - The appearance of this weed is
synonymous with its name in that it generally possesses
a distinguishable leaf, has weak and pithy stems,
sometimes a showy flower and often a large tap root.
Examples of this type of weed include dandelion, kochia,
bindweed, lambsquarter and henbit.
Both
types of chemicals will eliminate both types of weeds,
yet there are times when only one type of chemical
will eliminate a certain weed. For example: The dandelion
seed can be prevented from germinating by applying
a pre-emergent to your lawn. If however a dandelion
plant is already growing there the pre-emergent will
not harm the plant and in order to eliminate the dandelion,
you will have to apply a post-emergent chemical.
The
best insurance against any weed incidence is a healthy
lawn that is properly maintained. As every lawn and
landscape has thousands of tiny time bombs (weed seeds)
hiding in the soil, a pre-emergent program can be
an important part of this maintenance.
To
create a year long Pre-emergent Weed Barrier, you
will need 3 applications. This applies to all turfgrass
varieties:
Pre-Emergent
Schedule
figure
1.1
•
Depending on the pre-emergent chemical used, effective
time periods may vary (some chemicals will provide
control for 30 days and some up to 90)
•
Grassy weeds are more difficult to eliminate and the
pre-emergent application for them is critical for
your lawn to remain weed free. Grassy weeds begin
to germinate when daytime temperatures exceed 80 or
50 degrees soil temperature, so depending on where
you are located this may occur in April, May or June.
Your application needs to coincide with this temperature occurance.
•
Application 2 in the chart above (figure 1.1) can
be applied (May-June-July) to Grassy and Broadleaf
weeds, timing is important.
Post-Emergent
Schedule
|
There
is no recommended schedule for Post-Emergent
Applications as they are done on an as-needed
basis only.
|
|
Weed
Control
d)
n. – a weed is a
plant (of no value) growing in the wrong place
and at the wrong time.
