Well, I can tell you the best time to NOT have your sprinkler system come on. It’s in the middle of the morning. As I was out helping on some lawns this morning with my son Jake, this actually happened twice in one day in South Tulsa. Between the hours of 9:00 AM and 11:00 AM and right as we were about half done with fertilizing and spraying the lawns, the irrigation systems came on. There weren’t a lot of weeds present, so I was just spot-treating for those. With the sprinklers coming on right after I’d sprayed though, the weed-control won’t be as effective on these lawns. Thankfully, the fertilizer will be fine, as it needs to be watered into the soil.
Also, do not water the turf in the evening at this time of year, as this will increase turf disease pressure on your lawn. Leaving the turf damp all night, along with warm temperatures, is the perfect breeding ground for turf fungus to occur. It’s also not good practice to set your irrigation system to come on daily, as that is too much.
It is best to water deeply, but infrequently. About 2-3 times per week should be fine in June, before we get into our typical hot and dry weather pattern later this summer. Set your irrigation system to come on very early in the morning and have it be completed by sunup, or before your LawnAmerica guy gets there! There are other reasons why early morning irrigation is preferable. By watering in the early morning hours before the sun comes up and the winds increase, more of the irrigation water gets into the soil and is not blown away or evaporated away from the hot sun. Then after completing your watering, the sun will help dry out the moisture on the leaf blades quickly, which helps in turf disease prevention.