Issue: February 23, 1998


Lawn sprinkler setting

Question:

I moved to New Mexico from New York State last year and need information about how often to run my automatic sprinklers. I have a fescue lawn. I also have some bermuda grass. Does bermuda grass survive better here and require less water?

Answer:

You need to change the frequency of irrigation of each type of grass as the seasons change and as conditions change. Your specific soil type also affects irrigation frequency. In the winter, when temperatures are cool or cold, evaporation is less and plant water use is less (they still use water) so irrigation can be as infrequent as once a month on a clay soil or every three weeks on sandy soils. If you have experienced frequent snow or rain, you may be able to skip one or more months of irrigation. If the ground is frozen, the water cannot permeate the soil, so avoid irrigating areas in the shade while they remain frozen. As the spring temperatures and winds increase, you will need to increase the frequency of irrigation to compensate for the increased evaporation of water. At this time, though the plants may still be dormant, root growth is beginning and the roots need moisture to be healthy. So water once every two to three weeks, increasing to once a week as the grass greens. By mid-summer, you will need to irrigate every three days, or every other day, on sandy soil. Fescue has the ability to develop a deep root system if the soil is not too compacted or if there is sufficient depth of soil above rock layers. In the autumn, as temperatures decline, you can reverse the procedure and irrigate at the spring frequency. As it gets colder and the grass becomes dormant, change back to the winter irrigation frequency.

I didn't mention how long to run your automatic irrigation system - that depends on the soil type and the rate at which your system delivers water. When you irrigate the fescue, moisten the soil to a depth of at least a foot. This allows the soil to hold sufficient moisture to sustain the grass while the upper soil levels dry between irrigations to reduce disease problems.

As far as bermuda grass, yes it will tolerate less water. In your area it does well. It has the disadvantage of being very invasive because it spreads over the soil surface by means of stolons, or runners, and underground by rhizomes, which look like small bamboo sprouts. These rhizomes allow the bermuda grass to spread into flower gardens, vegetable gardens, into the cracks in pavement, and even penetrate thin asphalt layers in some locations. So, if the invasive nature of bermuda grass does not cause you problems, it may be a grass to consider.