Summer turfgrass doldrums
Tuesday, July 29, 2014 12:03 AM
By Curtis E. Young, Van Wert County Ohio State University Agriculture Extension Educator
Homeowners may be frustrated with the appearance of their lawns at this time of the year. Many lawns are pale green in color instead of the deep rich green color that it was in the spring. Why have lawns faded in their appearance? There are a multitude of reasons why lawns fade as the summer progresses. The following is a list of factors that alone or in combination can lead to lawns with poor color.
Factors that lead to dull or light colored grass in mid-summer:
• Mowing the turfgrass too short - The green color of turfgrass comes primarily from the blades of the turfgrass. The shorter that one cuts the turfgrass, the less of blade surface that remain to display the green color. What remains after being mowed short is mainly grass stems with limited color display. Additionally, grass stems without grass blades may die and turn brown in color. Turfgrass also produces seed in the spring. After seeds are produced or seed heads are cut off, the seed stems will die as well. The dead stems mixed in the lawn will dull the overall color of the lawn and will remain through much of the summer. OSU Extension turfgrass specialists recommend that turfgrass should not be mowed shorter than 2-2 1/2" and is better cut to 3".
• Mowing frequency - At each mowing, it is recommended not to clip off more than 1/3 of the total height of the grass to limit the amount and size of clippings thrown back on the lawn. To accomplish this, lawns may need to be mowed more than once a week. Clipping off more than 1/3 of the grass height may produce clumps and piles of clippings. Conditions under these piles of clippings are ideal for turfgrass disease development.
• Poor mower maintenance - Mower blades become dull through the growing season for many reasons such as regular use, cutting sticks and other debris, and scalping the ground when cutting too short. Dull blades tend to rip instead of cut the grass blades. Ripped blades have ragged edges which desiccate and turn brown again dulling the color of the lawn.
• Low nitrogen fertility - Turfgrass requires nitrogen fertilizer throughout the growing season. The fertilizer should be meted out over that growing season with applications of 1/2 lb. to 1 lb. actual nitrogen per 1000 sq. ft. typically applied in the spring, late summer and fall. It is recommended to be composed of both quick and slow release nitrogen sources. Additionally, supplemental iron may help to green a lawn if nitrogen alone is not greening the turfgrass.
• Insect and mite damage - There are a number of insects and mites that can damage turfgrass. Lately, mites have been increasing in population. Mite feeding injury appears as a white speckling on the grass blade.
• Turfgrass species - Cool season turfgrass species grow best in the spring and fall of the year and go dormant during the heat of the summer. Kentucky bluegrass is one of those species that goes dormant during the heat of the summer if it is not irrigated on a consistent and regular basis. Once the Kentucky bluegrass goes dormant, then more heat tolerant species take over such as fine fescues with thinner blades and lighter color than the bluegrass.
• Undesirable plant species - There are several "weed" species of grasses that may invade a lawn. Several of these species have a paler green color than Kentucky bluegrass. Examples of these undesirable grasses include annual bluegrass, crabgrass, rough bluegrass and nimblewill. Control of these undesirable grasses can be challenging, but doable.
• Turfgrass disease - There are several diseases that impact turfgrass in Ohio. Management of turfgrass diseases first requires identification. The plant and pest diagnostic clinic at The Ohio State University can assist in identifying diseases. For more information on submitting a sample, either contact your local Extension office or visit the clinic's web site at http://ppdc.osu.edu.
• Soil conditions - Soil compaction will limit root system development of turfgrass to a fairly shallow depth. Shallow root systems are susceptible to rapid drying, stress and reduced health. Soil compaction is corrected with core aeration that is best performed in the fall of the year.
• Poor irrigation practices - Frequent light waterings result in moisture reaching only shallow depths that promotes in shallow root systems (see above note on shallow root systems). It is best to apply 1" of water in one long watering once a week rather than multiple 1/4" or less waterings throughout a week. The 1" of water soaks deeper into the soil. One can measure how much water is applied by a sprinkler system by placing a square pan on the lawn within the area hit by the sprinkler system. Run and time the sprinkler system until water of 1" depth collects in the pan.
Diagnosing turfgrass problems requires careful analysis of environmental conditions and management practices. Corrective actions may be simple to complex depending on which problems need correcting. Turnaround time on the condition of the lawn may be a few days to several months to a couple of years depending on the existing problems. For more information on turfgrass problems, contact the OSU Extension office in Van Wert on the fairgrounds (1055 South Washington Street) by calling 419-238-1214 or emailing the Agriculture Extension Educator, Curtis Young at firstname.lastname@example.org.