Yup.. exactly . Running a sprinkler merely wets the top soil . Need rain to prevent fert burn . How many lawns have we seen over the years where the landscapers drop fert, and then it doesn’t rain for a week plus and bakes in the high sun angle. By then the damage to the lawn for the summer is done and they are torched and/ or die in many spots. By the same token don’t want an inch in a heavy downpour in 10 minutes . It’s tricky