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.