Irrigation ...Watering Tips

Many areas of the country regularly experience periods of dry weather during the summer. Irrigation is essential in these areas for maintaining attractive, healthy lawns. Lawns that are not properly watered become stressed and may brown and become thin. Weakened turf grass is more subject to certain disease problems, insect damage, and weed invasion.

Irrigation should wet the soil to a depth of 4-6". This depth in the soil is the area where most turf roots are growing. A loam or clay soil will be moistened to a depth of approximately 6" by 1-11/2" of water. A sandy soil will require 1/2 or 3/4" of water to moisten the top of 6" soil. Soils differ in the amount of time required to absorb a given amount of water. Clay soils have a very slow water infiltration rate, and it may not be possible to apply enough water to properly wet a clay soil before it begins to run off the surface. Place a container in the irrigation water pattern and measure the water collected in the container. If the water starts to run off the lawn before the desired amount is applied, move the sprinklers or stop the irrigation and resume after a period of time.

Regardless of soil type, it is more efficient to water lawns at the first sign of drought stress rather than wait until the lawn is dormant. Initial signs of water deficit in the soil is wilting  of the turn so that footprints in the grass do not spring back after walking on the lawn. An additional sign of drought stress is a blue or gray coloration of turf that is normally brighter green.

The time of the day watering usually is not critical, but watering in the heat of the day results in more loss of water to evaporation before the water soaks into the soil. watering in the morning results in more efficient use of the water. Watering in the evening is satisfactory unless the lawn has a disease problem. For many homeowners without automatic irrigation systems, late afternoon and evening is the only time of the day they can water the lawn.

Many grasses require 1-2" of water per week during normal summer weather. Hot, dry, windy weather may produce a greater water requirement.

Thatch intercepts and absorbs water, preventing water from infiltrating into the soil. Trapping the water in the thatch encourages the grass to have shallow roots, subjecting it to drying. Compacted soils where people walk or play have low water infiltration rates. Lawn aeration will improve infiltration of water in thatched lawns or lawns with compacted soils.

Roots from large trees often extend into the lawn area and draw moisture from the soil. More frequent watering may be required for turf under or near large trees.

Objects such as construction debris, sewers, or rocks buried in the soil will show up as localized dry spots. These spots will show signs of drought stress early before the remainder of the lawn and may require extra watering.

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