Since I have been in the business, I have been a deep and infrequent believer when it comes to irrigation on the greens. We'll run anywhere from 60 - 180 minutes of water from each head on greens and then shut them off for the next 4-7 days depending on the weather. Not only do we have a strong and healthy root system, but Poa annua doesn't do as well with this watering method with less water at the surface.
I was recently made aware of an article that Dave Wilber (@turfgrasszealot) shared about deep and infrequent watering, but not just on greens. We had a closed nine at the time since we were aerating so I decided to water the Mountain course fairways for 60-99 minutes.
I was skeptical at first since we were wet around the drains, which was expected, but our dry spots barely had a 1/2" of water. Either way, I shut off the irrigation for the following night and watched to see what would happen. I still needed to go out every morning and get some extra water on the dry spots (50 sprinklers vs. 400), but I didn't turn the Mountain fairway program on until Sunday evening which was 6 days later!
Entire profile is moist and
nice white roots coming
out the bottom
Our soil profile consists of 1-2" of thatch with some sand/ top soil mixed in and below that we have heavy clay. With the deep watering, I was able to wet the heavy clay on 75% of the fairway. I was actually able to get a soil probe into the clay which is not normal for August. When our surfaces start to dry out now, there is some moisture down below that is wicked up through capillary action.
After almost 8 years at Cinnabar, I feel I have stumbled upon something that may change the way I irrigate the course going forward. It has really got my brain churning and I couldn't be more excited. This is just one of the many reasons I love being a superintendent!