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New Mexico State University

New Mexico State University

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Maintaining Healthy Lawn Takes Hard Work

Healthy lush lawns need careful maintenance, said a New Mexico State University plant pathologist.

"Unfortunately, wanting a well-maintained, aesthetically pleasing lawn and actually having one are often two different things," said Natalie Goldberg, with NMSU's Cooperative Extension Service. "That's because turfgrass is susceptible to so many different types of diseases."

Goldberg said good management practices like watering, fertilizing, mowing and aerating can keep lawns healthy.

"It's important to provide lawns with adequate moisture, however there is a fine line between keeping the area too moist and too dry," Goldberg explained. Both dry and wet conditions can lead to plant diseases.

Many diseases require 14 hours of continuous wetness to penetrate the leaf surface, therefore avoid watering in the late afternoon and evening. It's best to water in the early morning, allowing efficient water use and providing adequate time for the grass to dry, Goldberg said.

Irrigate deeply so the water moves completely through the root zone, she said. "This will help develop a deep root system, which will tolerate extremes in temperature and moisture conditions better than a shallow root system," Goldberg said.

Goldberg said homeowners should water according to the lawn's needs instead of on a set schedule because the amount needed varies depending on the type of grass and time of the year.

"All lawns need fertilizer for strong growth," Goldberg said. "Some diseases prefer nutrient-starved turf, while others like large amounts of nitrogen."

In general, homeowners should apply 50 percent or more of the total yearly nitrogen in the fall, Goldberg said. "That's when cool-season grasses produce most of their tillers and that helps create a thicker lawn," Goldberg said. Applying fertilizer in the spring will help reestablish grass that was dormant during the winter.

Applying a slow-release nitrogen fertilizer may be useful, Goldberg said. "This will help provide an even source of the nutrient and avoid the flush of excess nitrogen, which triggers so many diseases," she explained.

Mowers should be kept in good working condition with sharp blades, Goldberg said. "Dull mower blades will leave jagged cuts, which will be more susceptible to attack by diseases than smooth, clean cuts," she said.

Avoid switching back and forth from short to tall grass. Changing grass from conditions that are too short to too tall interferes with the plant's production of carbohydrates and can stunt growth, Goldberg said.

Grass clippings can be left on the lawn if the grass is mowed properly. If the grass is too tall, excessive clippings will block light from the plants, Goldberg said. "The plants underneath the clippings will die, just as if you had placed a solid object on top of the grass," she said.

Aeration, which refers to air's ability to penetrate the soil, influences surface drainage, Goldberg said. "Thatch is a mixture of living and dead roots, rhizomes and runners that develops between the green vegetation layer and the soil surface," Goldberg said.

A little thatch is good, but if the thatch layer becomes too thick, it can interfere with air and water movement into the soil. Roots that grow into thatch are more susceptible to drought, high-temperature stress and diseases, Goldberg said.

Goldberg recommended aerification, thinning and raking, and vertical mowing to prevent excessive thatch. Aerification means punching holes in the turf to improve the movement of air and water. Thinning or raking on a regular basis will help reduce the thatch layer, Goldberg said. Vertical mowing is cutting by blades or tines, which move perpendicular to the soil surface and act like a mechanical rake, she said.

"These management practices will help maintain the lawn in a healthy condition. However, occasionally, pests will invade the lawn," Goldberg said. "It's important to identify the pest, select the appropriate means of control and apply the control at the appropriate time."