Irrigation involves the use of a precious natural resource that is in limited supply at various times in many parts of the earth.  Many grass varieties which are irrigated do not require irrigation and will go dormant and stop growing during dry periods and even droughts and then resume growing when the conditions are favorable.  In 2012, the Midwest experienced record droughts.  In central Illinois the drought turned lawns that were not irrigated brown and left homeowners wondering if the grass was dead.   Many cities imposed water use restrictions and guidelines as drinking water reservoirs fell below normal levels.  As the rains came and the summer heat subsided, life came back into the grass and after several weeks lawns were green again.  If you do irrigate, do so responsibly and consider the following.
 

Before using the irrigation system each season evaluate the irrigation system to ensure that water is distributed evenly across the lawn and measure the water application rate to determine how long the system needs to run to meet grass water requirements.  Adjust irrigation emitters so water does not fall where it will be wasted on areas such as driveways, roads, sidewalks etc.  Contact your irrigation company if adjustments are needed.
 

Do not exceed the water holding capacity of the soil by allowing water to run off the lawn into areas where it will be wasted and possibly carry soil, grass clippings and nutrients that may become pollution.
 

Use a rain gauge and factor in water from rainfall when determining when and how long to run the irrigation system to meet grass water requirements.   Don’t irrigate when it is raining.
 

It is also recommend that an instrument be used to measure soil moisture to assist in determining when to water.
 

The publication, Turfgrass Maintenance in the Midwest, recommends for common cool season grasses in the Midwest, 1 to 2 inches of water each week of the growing season if maintaining a green lawn is a priority.  Check with knowledgeable persons in your area to determine the water requirements for the grasses in your lawn and manage your irrigation system accordingly.
 

Irrigate early in the morning to reduce the amount of water lost to evaporation and to decrease the chance of fungus.
 

When the amount of water supplied by rainfall begins to fall short of grass needs, it is recommended that irrigation not begin immediately to encourage grass roots to grow deeper in pursuit of water.  Deeper roots will help increase the vigor of the grass.  Begin watering before the grass goes dormant.
 

Established lawns respond best to infrequent deeper watering while newly seeded or recently established lawns with shallow roots respond favorably to more frequent watering until root systems are developed.

 

In addition to irrigating responsibly choose organic lawn care.
 

References:
 

The NOFA Organic Lawn and Turf Handbook. (First Addition, March 2007). Organic land Care Committee of the Northeast Organic Farming Association, Connecticut and Massachusetts Chapters
 

Turfgrass Maintenance in the Midwest. (1997). University of Illinois at Urbana-Champaign, U5009.

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​Earth Friendly Land Care, Inc. (February 2013)