A common problem we hear in the heat of summer is, “I have a dead spot in my lawn.” The majority of the issues are irrigation related. One cause of improper sprinkler coverage is sunken sprinkler heads. Sprinkler heads settle after a few years (ours needed to be raised 3 years after installation) and are too low to reach beyond a small area. We call them crop circles and once you know what to look for you will spot them yourself. The picture below shows two definite crop circles, that were visible from the street.
Healthy grass in green circles around sprinklers heads while the surrounding lawn is brown. If you look closely you see the grass surrounding the sprinkler head is flat because the water hits at a low angle and the grass blocks the water. The below pictures show extreme examples. You can prevent your lawn from getting to this point by turning on your sprinkler system and observing the sprinkler head level and assessing if they need raising.
The below picture shows a sunken sprinkler head. Hard to see at first and definitely needs raising! Simple and common problem which needs to be addressed since it can cause drought stress in a lawn quickly in summer.
Digging up the surrounding grass and packing dirt and even putting a rock underneath the sprinkler head will raise it from it’s sunken state. The after picture below shows how much of the sprinkler head was buried before. Now the heads are proper height, the coverage will improve and the lawn will begin to recover after a couple of weeks. If you do not feel comfortable raising your own sprinkler heads, there are irrigation specialists who you can hire to do this for you.
Another potential cause of brown spots is overgrown landscaping such as bushes or trees, blocking the sprinkler path. Below is a great video from CSU highlighting this common cause of brown spots in lawns. Turning on your system and evaluating it annually is a necessity in Colorado and even periodically throughout the season.