Summer Lawn Care - Marion County
Summer Tips for the Lawn
By Steve Mayer
Extension Educator-Horticulture
Purdue Extension-Marion County
Lawns need some attention during the summer to keep them looking good. However, practices such as grub control and irrigation are not always necessary.
If you had a severe white grub problem in the lawn last year, consider applying one of the preventative insecticides in July. Many products containing halofenozide or imidacloprid are available.
However, if you did not have significant grub problems last year, you may want to try a "wait and see" approach. Research has shown that many grub control applications are wasted because grubs were never present.
In this line of attack you need to monitor for grubs about mid-August by cutting into the soil at several locations. A curative insecticide treatment, such as trichlorfon or carbaryl, is needed only if soil sampling indicates 5 or more grubs per square foot.
Avoid frequent, excessive lawn watering in July. This attracts egg-laying adult Japanese beetles and increases white grub egg survival. Japanese beetles usually lay few eggs in non-irrigated turf or under trees.
Determine the frequency of normal lawn watering by the appearance of the turf. Before irrigating, look for a bluish-green color, the first sign of water stress.
To look good, lawns may need 1-1.5 inches of water per week during hot, dry summer weather. It is best to apply this amount at one time. If necessary, make two equal applications of water 3 to 4 days apart.
Avoid daily, light irrigations. This promotes shallow rooting, reduces drought tolerance, and encourages crabgrass and disease. If changes in watering frequency are made during the summer, make the adjustments slowly so the turfgrass plants can adapt.
Early morning is the best time to water (ideally between 4 and 8 a.m.). It will result in less water loss, more even coverage due to less wind, and less potential for disease problems.
If you do not mind a brown lawn, it is not necessary to water established turf during a drought. The lawn will naturally go dormant to survive. Generally a healthy dormant lawn can survive about 4 weeks without water before significant turf thinning occurs. However, in extended drought conditions, water once about every 4 weeks.
Avoid traffic (mowing, walking, etc.) on a dormant lawn because it will damage the grass and decrease its chance for survival. Herbicide applications are not recommended on drought-stressed or dormant turf. The applications are not very effective at controlling weeds plus they can damage the grass.
Try to use little, if any, fertilizer during the summer, especially on non-irrigated turf. Applications applied now tend to promote shoot growth at the expense of root growth. Too much nitrogen during the summer may prompt more disease problems.
With enough moisture, the grass will continue to grow. To avoid plant stress, mow frequently. Cut off no more than one-third of the grass leaf blade at any one time. Continue to mow tall (3.0-3.5 inches) but do not suddenly change the mowing height. It may take 4 to 6 weeks for the grass to compensate for an increase in mowing height.
Examine the mower blade to make sure it is still sharp. A dull mower blade will leave ragged leaf tips. This can result in a whitish cast when viewing the lawn from a distance. Bruised turfgrass blades stress the plant and provide a good opportunity for some disease organisms to infect the plant.
Questions
Q. Where can I find more information on lawn selection and care?
A. Purdue has an extensive list of lawn publications. They are online here.
Q. How do I control nimblewill and zoysia in my bluegrass lawn?
A. You only have two options for dealing with these perennial grass weeds. You can either live with them or use a non-selective herbicide containing glyphosate. This herbicide will try to kill everything green it contacts so spot treat the weeds this summer and reseed in mid-August. You may want to begin treating actively growing weeds in July to allow time for retreatment before seeding. For more information, read Purdue publication AY-11.
Q. I have leaf rust disease in my lawn. What should I do?
A. Early leaf rust infections may occur in the lawn at this time. For severe infections, apply a half rate of a slow release high nitrogen fertilizer. For more information, consult Purdue publication BP-110.
Steve Mayer is Extension Educator-Horticulture with Purdue Extension-Marion County. He coordinates the Master Gardener program in Marion County. To contact a Master Gardener, call (317) 275-9292, or e-mail: marionmg@purdue.edu
Photo Credit: Steve Mayer
Purdue University, Indiana Counties and U.S. Department of Agriculture Cooperating. An Affirmative Action/Equal Opportunity Institution.
July 2004
