Spring grass seeding
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[MARCH 14, 2006]
With moisture falling around the county in the
past week, many may be willing to gamble on trying to establish some
grass from seed. Along with seeding, timing in the spring is
critical for some additional operations. Let's start with crabgrass
control. Crabgrass is an annual grass, meaning it comes up from seed
every year. One of the best ways to control annual weeds is to use a
seed germination inhibitor that works on that germinating seed. The
only problem is timing. These herbicides must be put on before you
see the weed -- in this case, the crabgrass.
Many of the germination inhibitors are combined with fertilizer.
They should be applied about April 1 in our area, but the timing
can vary a couple of weeks. The crabgrass seed germinates on the
basis of soil temperature, and soil temperatures need to be
about 55 degrees for seven to 10 consecutive days. Without a
soil thermometer and a continuing log of soil temperatures, one
of the good indicators is forsythia in bloom. If you don't have
your crabgrass preventer on by the time you see forsythia
blooms, you had best get it on quickly. Another thing to keep in
mind is that the same product that prevents crabgrass from
germinating will do the same thing to other seeds. This means
that you can't sow new grass seed and use a crabgrass treatment
at the same time of year. If you need seeding done, fall seeding
is actually the best.
Grass may be sown either March 15 to April 1 or Aug. 15 to
Sept. 10. Spring seedings don't usually have the success that
the fall ones do, because hot weather tends to hit before lawns
become well established. Last fall was an exception, when the
dry fall actually had seed lying dormant for months. Seeding
rates should be about 4 pounds of seed per 1,000 square feet for
bare dirt and half that rate for over-seeding thin areas. We
recommend using a blend of grasses such as Kentucky bluegrass, a
fine fescue and perennial ryegrass. You can actually buy the
seed pre-mixed from retailers. Some people leave out the
perennial ryegrass, but it does provide quicker germination and
The seeding times are also good times to use a plug aerator
or a power dethatcher. These operations are very hard on grass,
and doing them when the grass recovers quickly goes a long way
to keeping your lawn healthy. Both of these operations are
usually done to help remove thatch layers. This thatch should be
no more than one-half inch in depth, or you'll tend to have
disease problems come in.
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Fertilizer and broadleaf weed control are best applied in May
when they work better. This early in the season, lawn weeds aren't
actively growing, and turf isn't growing actively enough to make
good use of nitrogen fertilizer. Many broadleaf weed killers need
temperatures over 50 degrees to work properly.
Another item I am getting several calls on is grubs and moles.
The two are often related. Moles eat grubs and earthworms for food.
This really isn't a good time to try to control grubs, since they
are large in size and won't be around too much longer. They will
pupate this spring and come back out as June bugs, Japanese beetles
or green June bugs to start the process all over again. The best
control time is from August through September.
Mole control is best accomplished by doing away with their food
source, so they go elsewhere. Since newer grub controls don't result
in the same reduction of earthworms as diazinon did, insecticide
treatments may not eliminate enough of the food source to be
effective. Also, with this not being a good time for grub control
anyway, you are reduced to trapping for moles. The loop-type and
scissor-type traps seem to work better than the harpoon traps.
Hopefully these spring lawn tips will get you started on the
right track for the year. If you have further questions, feel free
to contact the office at 732-8289.
Fulton, unit leader,
University of Illinois Extension,
Logan County Unit]