July 15, 2017

1 - Summer lawn problems can be due to several stresses.

Yard and Garden July 15, 2017

Q.

We have a small grass area (6 feet by 33 feet) in our back yard. We water it on watering days. It was laid down last October. It was mostly green with two very small yellow patches where our dog had urinated. I did mow the small lawn with a non-electric mower.

We recently left town for a week. When we returned, much of the grass had turned silver-grey and was drooping. We have watered it, but most of the silver-grey areas have turned yellow.

I wondered if you may have any suggestions about restoring the lawn, and/or about future watering or other (Miracle Grow?) treatment?

- Jeff B.

A.

It is not possible to definitely identify the problem by e-mail, but I can suggest some potential causes and solutions. If the lawn was not irrigated for the week while you were gone, it is probable that it dried. Was the grass irrigated with an automatic irrigation system? Is there a chance a power outage changed the irrigation settings? The silver-grey appearance suggests it dried out. Grass also rolls its leaves when it is dry. The yellowing may indicate that the stress was enough to cause the leaves to die. If the crown of the grass (where the leaves originate) or rhizomes if it is a spreading grass have survived they will display new growth in a couple of weeks. The most important treatment is irrigation – not too much, nor too little. Plants with reduced leaf surface will need less water, but cannot be allowed to become completely dry.

Is there a chance the lawn was overwatered and remained waterlogged while you were gone? This could cause death of roots or even the death of the grass plants. Once again, if the roots died, the plants will exhibit symptoms of drying. If the problem was not too severe the crown of the plants may have survived or other plant parts such as rhizomes or stolons may survive. These may then develop new roots and leaves. Again, the best treatment is proper irrigation.

Another possibility for injury could be salt burn from fertilizer salts. Was the lawn fertilized just before you left? In the heat that has beset New Mexico at the end of June and early July salt burn becomes a possibility. Once again, irrigation is the proper treatment.

Disease is also a possibility either directly or secondarily after a stress event. A sample of the grass (taken from the boundary with both healthy and dying grass) can be taken to your local NMSU County Extension Service office. The Extension Agent may be able to diagnose the problem on site, or can send the sample to the Plant Diagnostic Laboratory in Las Cruces. This is a good practice to make sure that disease in not present in the lawn, or if it is to begin treatment as soon as possible.

All of the suggestions above depend upon the type of grass. Is the lawn a warm-season grass that normally tolerates heat, or a cool-season grass that may be going dormant in the heat? The type of grass also impacts how readily it can recover from stress. Your County Extension Agent can advise you about these issues as well.

For more gardening information, visit the NMSU Extension publications Web site at http://aces.nmsu.edu/pubs/_h, or to read past articles of Yard and Garden go to http://aces.nmsu.edu/pubs/periodicals.html.

Send your gardening questions to Yard and Garden, Attn: Dr. Curtis Smith at cwsmith@nmsu.edu or leave a message at https://www.facebook.com/NMSUExtExpStnPubs.

Curtis W. Smith, Ph.D., is an Extension Horticulture Specialist, retired from New Mexico State University's Cooperative Extension Service. NMSU and the U.S. Department of Agriculture cooperating.