Forrest Rose
Information Specialist
573-882-6843
RoseF@missouri.edu
March 5, 2003
A healthy, weed-free lawn
begins with spring regimen
"Cool-season grasses such as bluegrass, fescue and ryegrass grow favorably during this cool weather," said Brad Fresenburg, extension research associate at the MU Turfgrass Research Center. "Improving air, water and nutrient movement through the soil during this time significantly increases the quality of the grass."
The first step, aeration, reduces soil compaction, increases air exchange and allows water to percolate more quickly into the soil to create better root mass, he said. "Increasing root mass at this time of the year greatly improves the chances of cool-season grasses to reduce stress and survive the heat of the summer."
Fresenburg recommended aeration equipment that force hollow tines into the soil instead of pull-type drums with tines. "A machine that pulls half-inch diameter plug 3 to 4 inches deep on 4-inch centers will do an excellent job," he said.
The best time to apply fertilizer is just after aeration, "to move nutrients immediately into the root-zone of your lawn," he said. "This practice has shown excellent results in the density and color of cool-season grasses in preparation for summer stress."
Many types of quick-release fertilizers are available, and most of these work well for spring application, he said. "Applying one-half to one pound of nitrogen per 1,000 square feet would be acceptable from early March to early April."
"Weeds are opportunistic and invade weakened lawns," Fresenburg said. "When you're trying to keep your lawn weed-free, the saying, 'The best defense is a good offense' holds true."
Planting the right turf species, reseeding bare areas, and proper fertilization, watering and mowing can keep weeds at bay. "The height of mowing influences competition against weeds such as crabgrass," he said. "The higher the cut, the lower the crabgrass infestation.
"Optimum watering practices involve less-frequent deep-soak watering to encourage a deep, healthy root system and maintain a dry surface area where weeds get their advantage," Fresenburg added. "Frequent light sprinkling encourages shallow-rooted weeds and seed germination."
Crabgrass, the curse of home laws, germinates in the spring and thrives in the summer heat, he said. "In the spring, the new crabgrass seedlings emerge around the previous year's plant unless this open space is reseeded during the fall with a desired grass, and a pre-emergent herbicide is applied to kill the germinating crabgrass seedlings."
To be effective, a pre-emergent herbicide must be applied before crabgrass seedlings and other weeds begin to emerge, which occurs when daily high temperatures reach about 70 degrees, Fresenburg said. "Our general rule is that for areas in the southern half of Missouri, application should be made by March 15; for the northern areas, application should be made by April 15.
"A natural guide that's specific to each year's fluctuating weather patterns is to have your pre-emergent herbicide in place before the yellow blooms of the forsythia have all dropped," he said.
Source: Brad Fresenburg (573) 443-4893
| Return to Current News Releases | |
|
College of Agriculture Food and Natural Resources
AgEBB |