Most systems have a combination of two head types: rotors and sprays. Rotor heads rotate to cover the area they are watering. Spray heads cover the entire area they water, for the entire time the zone is scheduled to run. As a general rule rotor heads should run twice as long as spray heads. When conditions become dry and the need for spring watering begins, set rotor zones to run 30 minutes in each zone and spray heads for 15 minutes. Run frequency should be every 2 days. More specific adjustments in run times should be made after several run cycles have been completed. Observe wet and dry areas while mowing to determine more precise watering times.
Spring Run Times (April-May)
Summer Run Times (June-August)
Most systems should be effective watering 60 minutes per zone for rotor heads and 20-30 minutes for spray heads every other day. Sprinkler system controllers will also have a global adjustment feature that will allow all spring run times for all zones to be increased in 5%-10% increments for all zones. As a result once your systems run times are established in the spring they should be able to be adjusted with the global adjustment feature all season long.
Fall Run Times (September-October)
As the length of daylight declines late August into September, adjustments should be made to reduce frequency and/or length of run times. Less frequent and deeper watering is always better for your lawn. Maintain summer run times, reducing days to water to every 3 days in September and every 4 days in October. Lawns naturally develop deeper root systems in the fall. Deeper, less frequent watering will encourage root development.
Time of day to water
The ideal agronomic time of day to water turf is 6:00 am through 2:00 pm, however many cities may limit day time watering because of evaporation. You should start your system earlier during the overnight hours to accommodate any watering restrictions your municipality may enforce. It is always better to water outside of the ideal time range than to not water at all.
General rules for cool season turf grass water needs
- Usually requires 1 inch of water per week.
- Can be watered 1 inch per week in 1 watering per week spring and fall.
- Should be watered ½ inch every 4 days in the summer June–July.
- Most municipal water supplies cannot supply enough water for home lawn irrigation systems to deliver one inch of water in one day or ½ inch every 4 days.
- Restricted watering hours, days, and limited water supplies all contribute to the need of an irrigation system that is properly zoned for the available water supply.