Having an irrigation system is a huge advantage, but it can potentially cause more harm than good. Each system must be properly calibrated to apply the correct amount of water at the proper time. Daily watering and evening irrigation can both promote diseases, like Brown patch. The rule of thumb is to provide your lawn with 1 inch of water per week with as few watering sessions as possible.
We recommend 1-3 times per week only during the early morning hours. If you decide to water twice a week, you’ll need to make sure each zone in your lawn is receiving 1/2 inch of water each time the irrigation runs. The only way to know how long each zone should run is to scatter empty (tuna) cans throughout the zone and to let the system run until the proper amount of water is in each can. This process takes some effort, but it assures your system is properly calibrated. No matter how good your irrigation system is, nothing beats a slow, steady rain.
Irrigating after seeding and aeration is different. Frequent short watering (2-3) times a day is ideal for about 2 weeks. This will encourage the seeds to germinate quickly and become established. After 2 weeks resume a normal irrigation schedule.