Horticulture Hotline 02/06/17
By Bill Lamson-Scribner
The soil temperature indicates that it is just about time to
apply preemergent products to your beds and turf. Valentine’s Day and the
running of the Daytona 500 are just around the corner. The time to apply the
magical weed preventer is coming up fast, and this year, since our winter has
been pretty mild and the ground has been insulated with moisture,
the time might come a little early.
Depending on which Phd doctor you believe, crabgrass
germinates when the soil temperature (3 inches deep) stays above 55 degrees
(some people say 57 degrees), for 3 straight days provided adequate moisture in
the soil. Now some doctors say remains 57 degrees or above for 24 hours at a
depth of 3 inches with adequate moisture.
If you are not in to monitoring the soil temperature, Valentine’s Day or
the running of the Daytona 500 should work for you. Spreading a preemergent
product now could save hours of spot spraying later.
The turf areas as well as the landscape bed areas will
greatly benefit from the use of preemerge products. Not only will the yard look
better, but your plants will not have to compete with the weeds for sun,
nutrients, and water. If you are controlling weeds with preemergent products,
there are less weeds there for you to spray or pull, saving you time. There is
also less stress on you trying to find time to control the weeds in your yard later
once the weeds have emerged. Control them now with a preemergent control
product!
For those new readers of the Horticulture Hotline,
preemergent control products kill weeds as they germinate. The weeds never come up and you never have to
worry about them. Crabgrass, goosegrass,
barnyardgrass, crowfootgrass, dallisgrass (seedling), foxtail, annual
bluegrass, smutgrass, barley, kikuyugrass, wild oats, bittercress, carpetweed,
chickweed, Carolina geranium, henbit, knotweed, lespedeza, marestail, black
medic, mustard, oxalis, pineappleweed, pigweed, redroot, parsley-piert,
purslane, rocket, shephardspurse, speedwell, spurge, and woodsorrel are
examples of weeds controlled by preemergent products. Small seeded annual weeds are controlled by
preemergent products.
Read the label of the specific product that you are using to
get an exact list of weeds that the manufacturer has tested and shown to
control. Preemergent products applied now do not control winter annual weeds
that are already up like annual blue grass. To control annual bluegrass, you
would have used a preemergent in August and again in October (this could vary
with products and rates).
Clover, Florida Betony, Nutsedge and Dollar weed are not
controlled by preemergent control products.
These are perennial weeds. Weed Free Zone is a liquid that will do a
good job on controlling many of your broadleaf weeds. The Nutsedge will require
a different product and is most likely not visible right now. It is important to control these weeds now
before they go into their reproductive stage.
A weed in its reproductive stage is harder to control than a weed in its
vegetative stage. By controlling the weed now you avoid having to deal with
more weed seeds next year.
It is very noticeable when you ride through the Lowcountry
which homeowners and which businesses used preemergent products last fall at
the correct time. One business or home lawn will be nice and brown and dormant
without a spec of green in sight. Right next to it will be brown turf mixed
with green weeds. Again, it is very important to control those weeds now before
they begin to flower.
Always read, understand and follow product label. The
product label is a Federal Law.
