Three factors are critical in lawn irrigation: frequency, timing and amount of water. Early morning is the most effective time to irrigate due to reduced evaporation. It is also better to provide the turf with water before mid-day when the evaporation rate is the highest.
Watering in the evening can also be done, but may favor disease development, particularly under cool night temperatures. Most disease-causing fungi require several hours of leaf wetness for infection and disease development to occur.
A lawn that requires irrigation will exhibit various symptoms. If footprints remain while walking across the lawn, the turf has reached the wilting point and should be irrigated. A slight change in color to dark blue-green and grass blades folding inwards can also be observed when water is required.
Seasonality
Your watering patterns should change as the season’s change. Your lawn needs a lot less water in April or May than it does in July or August. If you have an automatic irrigation system you should adjust your clock monthly to account for seasonal variations. Depending on where you live you need to make smaller or larger adjustments.
Table 1 shows a sample monthly irrigation schedule that shows the approximate percentage of total irrigation water use (based on ET) that should used during each month of the irrigation season. Keep in mind that this is only a sample schedule and may not apply to your climate or region. Contact your local water utility, horticulturist, or agricultural extension agent for a similar schedule for your specific region.
Table 1: Sample Monthly Irrigation Schedule
| Month | Percent of ET and Percent of Total Annual Irrigation Use |
| April | 11.5% |
| May | 12.5% |
| June | 16.0% |
| July | 20.5% |
| August | 19.0% |
| September | 13.5% |
| October | 7.0% |
| 100.0% |
Lawn Irrigations Audits
Some water providers, cities, and utility companies offer irrigation audit services to their customers. A representative from the local water provider will come to your home evaluate your current landscape and irrigation system, identify areas for improvement, and provide a new watering schedule all of which will help you save water.
For information about irrigation audits in your area, contact your local water provider.
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- Water-Wise Plants Timing and Seasonality - January 13, 2017