Worse than Irrigation running in the rain?
Irrigation running all spring!!….Your lawn needs deep roots; down where it is cool and damp when the heat of summer comes. Best way to get them down there is to let them go looking for it now. Watering early in the season makes roots lazy. They stay on top, where they will be susceptible to insects and sun later on. Watering now can cause fungus and disease problems later. Watering now encourages weed seed germination. Watering now breeds mosquitoes and ticks, so...
WAIT TO IRRIGATE!
Don’t run your system until the weather is hot and dry. Lawn grass will need watering when it wilts. How will you know? Wilted grass shows your footprint. Generally, late June.
Contrary to conventional wisdom, letting your lawn dry out is actually good for it. Periods of dryness allow the grass to develop deeper, stronger roots that are better able to resist pests, weeds, and drought conditions over time. Too much water promotes fungal growth and nutrient run off, and creates ideal conditions for mosquitoes and other water-loving pests to flourish. Plus, why waste water that your grass doesn’t need anyway?
Rule of thumb for well-established lawns: Wet the soil 6" down, then allow to dry 4-6" down before watering again. How to tell? Dig a hole or use a soil moisture meter.