Cold

Our sprinklers go on at 2 am on Thursday mornings.  I was up late and heard the sprinklers go on. I thought it was bad for the sprinklers to be watering the grass and the plants because it was freezing outside.  I have heard that the orange farmers water their trees when it is cold to save them from the frost.  But it didn't help our grass or plants.  Everything was killed by the frost.