August 12, 2017

1 – Excess water may cause damage to lawns in New Mexico, but there are other problems to consider as well.

Yard and Garden August 12, 2017

Q.

I have noticed over the last few days that patches of grass in my lawn seem to be dying. With all the rain we have had in Las Cruces over the past week or so, I have not been watering. Is it possible the grass is getting too much water from all the recent rain and that is what is killing it?

- Gigi Z.

A.

It is possible that the rains have created problems for your lawn. The worst case is that the grass has become infected with a disease. Your local NMSU County Extension agent can help you determine if this is the case. Take a sample of the lawn to your Extension agent early in the week to be sent to the Plant Diagnostic Laboratory at NMSU to determine if there is a disease present. Collect a sample of the lawn (leaves, stems, and roots) from an area that includes healthy and symptomatic grass.

Other potential problems are associated with waterlogging of the soil interfering with the function of the roots even without a disease infecting the grass. I have seen lawns recently and in past years that developed a yellowish color in lower areas of a lawn where water collected. This chlorosis (yellowing) often vanishes as surplus moisture drains. This problem will be most likely to occur in sunken areas to which water drains and in clay soils that do not let water drain away readily.

Another possibility may be that the grass is not getting enough water. Since you are not watering, especially if your lawn is in sandy soil and used to frequent irrigation, the soil may not be receiving and retaining enough moisture and the grass may be drying. A similar result can occur if there is a thick layer of thatch (dead stems and roots) accumulated in the lawn. When thatch layers become dry, they are difficult to remoisten and may actually shed water from higher areas of the lawn. These areas may then display desiccation and dying of the grass. Such areas of dry thatch often reveal themselves when they are watered by making the sound of water hitting cardboard. You can also cut through the turfgrass layer and look for a thick layer of dead stems and roots. Aeration to allow water to permeate thick thatch layers is helpful as is removal of some of the thatch. Your NMSU County Extension agent can advise you as to the best time to remove thatch based on your type of lawn grass and location. A thin layer of thatch is beneficial, but when it accumulates it can cause problems.

Insects may also be the cause of dying areas of lawns. Your NMSU County Extension agent with the Plant Diagnostic Laboratory can help you determine if insects are involved and help determine an appropriate treatment if required.

And now dear readers, a much anticipated announcement: For over 22 years I have had the honor of writing the Yard and Garden column as NMSU Extension Horticulture Specialist and in retirement, but that time is drawing to a close. Dr. Marisa Thompson has assumed the duties of NMSU Extension Horticulture Specialist and will soon be answering your questions in the Yard and Garden column. I will continue writing for a brief period as Dr. Thompson gets settled into her office and the many aspects of her job, but you will notice that it is her contact information provided at the end of this column. I will soon begin writing a garden blog, so I hope I will be able to see my friends online as I do that. I hope to see you at SouthwestGardenSmith, but please also use the resources of NMSU’s County Extension offices and rely of the great expertise of Dr. Thompson. I remain your garden friend, Curtis Smith (SouthwestGardenSmith).

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. Marisa Thompson at desertblooms@nmsu.edu or leave a message at https://www.facebook.com/NMSUExtExpStnPubs.

Marisa Y. Thompson, PhD, is an Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, office: 505-865-7340, ext. 113. NMSU and the U.S. Department of Agriculture cooperating.