Spring rains and warmer temperatures have brought beauty to our yards — bright-yellow daffodils and, for most of us, lush green lawns. Of course, a few folks are happy with anything that’s green, but most prefer a lawn free of weeds.
What’s the best way to defend against weeds, insects, and disease? The answer’s
simple: Encourage a dense and healthy stand of turfgrass. That means selecting
the right turfgrasses, applying the correct kind and amount of fertilizer, and
properly mowing and watering your lawn.
Don’t underestimate the importance of mowing turfgrass to the proper height.
Turf cut too short has a shallow root system and allows weed-seed germination.
Most turfgrasses should be mowed to a height of two to three inches. Remove
no more than one-third of the grass blade in a single mowing to help maintain
turf’s root growth. This means mowing when the grass is three to four inches
tall. Maintaining turfgrass at the proper height deters weed-seed germination
by keeping the soil surface shaded. Annual grass weeds are more aggressive on
lawns mowed to less than two inches. Keep mower blades sharp; ragged grass blades
can invite leaf-disease problems.
One of the most common garden questions in the spring is “When do I apply
crabgrass control to my yard?” Keep in mind, weeds will thrive only if there
is space for them, so the best way to prevent annual grass-weed invasion is
to encourage a dense stand of vigorous grass.
Eliminating weeds is of little value unless enough desirable grass is present
to fill in bare spots. And remember, not all grassy weeds are crabgrass; properly
identify a weed before selecting a treatment to eradicate it.
Pre-emergence herbicides are the best way to control crabgrass. They’re generally
effective when applied before the annual grass weeds emerge. Some common annual-grass
herbicides are benefin, benefin/trifluralin, bensulide, dithiopyr, oxadiazon,
pendimethalin, prodiamine and siduron. All provide good to excellent control.
Timing is crucial: Apply crabgrass preventers approximately two weeks before
germination; in central Illinois, this means early to mid-April. Most pre-emergence
herbicides are good for four to six weeks after being applied. Crabgrass will
start to germinate when the soil temperature remains at55 degrees Fahrenheit
for seven to 10 consecutive days. For maximal effectiveness, apply preventer
uniformly across the lawn, making sure to read and follow all directions on
the label. Pre-emergence herbicides are more efficient when watered within one
to three days of application. With the exception of siduron, pre-emergents should
not be applied to newly seeded turfgrasses.
For more information, visit the University of Illinois Extension Lawn Talk
Web site at www.urbanext.uiuc.edu/lawntalk/index.html.
Kids’ gardening program
The University of Illinois Extension is offering a telenet, “Kids’ Gardening,”
at 1 p.m. Tuesday, April 13, and 7 p.m. Thursday, April 15. This program is
full of great ideas for creating a children’s garden in any community.
Monica David, state master-gardener coordinator, will share tips on developing
a team of dedicated volunteers to take on a kids’ garden project, how to develop
community support and how to find financial assistance.
She’ll also share great educational ideas for future gardeners to enjoy while
learning about gardening.
There is $2 charge for the program, which is being held at the University
of Illinois Extension Building on the Illinois State Fairgrounds in Springfield
with the use of the University of Illinois Extension telenet system.
Call 217-782-4617 to reserve a seat and an information packet.Â
This article appears in Apr 8-14, 2004.
