Achieving a clean, uniform lawn cut is challenging where turf meets fixed irrigation components. Mowing directly over sprinkler heads can damage the plastic housing or internal mechanisms, potentially leading to costly repairs and water inefficiency. The goal is to maintain a manicured appearance without causing mechanical damage or creating uneven spots. This process requires careful preparation, specialized power tool techniques, and precision manual work.
Preparing the Area for Trimming
Before cutting, the exact location of each sprinkler head must be clearly established. Overgrown grass or heavy leaf litter can easily obscure the heads, making them vulnerable to accidental strikes. Clearing away debris ensures the entire top surface of the head is fully visible. A properly installed head should be flush with the soil surface, allowing the mower to pass over it without contact when retracted. If the head is buried too deep or sitting too high, it risks scalping the grass or damaging the equipment, indicating a need for adjustment before trimming.
String Trimmer Techniques
The string trimmer, or weed whacker, is the primary tool for cutting grass immediately surrounding the sprinkler head, but it requires a controlled approach to prevent damage. The nylon string line, rotating at high speed, can easily fracture the plastic risers and caps. Operators should approach the head at a slow, steady pace to maintain precise control over the cutting line.
The most effective method involves using a shallow, near-vertical cutting angle, rather than a horizontal sweeping motion. A horizontal technique, often called “scalping,” can carve a depression around the head that is detrimental to the turf’s health. The vertical angle allows the operator to trim the grass blades without the string making direct, sustained contact with the head’s housing.
The trimmer’s guard can be used as a physical guide to maintain a safe distance from the plastic components. By holding the trimmer so the string line is on the far edge of the grass clump, the operator can shave the blades down gradually. This prevents the high-impact force that occurs when the string hits the rigid plastic at full speed, mitigating the risk of structural failure.
Precision Edging and Manual Tools
For the most detailed and safest finish, power tools should be supplemented with manual precision tools. Even with careful string trimming, some blades of grass may remain, requiring a more defined edge. Hand shears or small, specialized sod knives offer the necessary control for this fine work.
These manual tools allow for a clean cut right up to the base of the head, ensuring no grass blades obstruct the spray pattern when the head is active. Some lawn care professionals use a cylindrical sprinkler head trimmer, a tool designed to cut and remove a neat, circular ring of sod about 4 to 8 inches in diameter around the head. This technique creates a small, defined border, sometimes referred to as a “sprinkler donut,” which simplifies future trimming and prevents turf encroachment.
Creating this slight buffer zone ensures the turf does not grow over the head, which can prevent the pop-up mechanism from fully extending. When using a manual sod cutter or trowel, the cut should only penetrate the top layer of turf and root zone, typically no more than 2 to 3 inches deep. This maintains the structural integrity of the surrounding soil while providing a clean, defined space that is easy to maintain.
Protecting Sprinkler Heads
Long-term maintenance focuses on preventing physical damage and turf overgrowth. Sprinkler heads should be maintained so the top surface remains level and flush with the surrounding soil grade. If a head sinks below the turf line, it can be struck by the mower blade, leading to catastrophic damage.
Sunken heads can often be raised by carefully removing the surrounding turf and adding a riser or extension between the water supply pipe and the sprinkler body. Conversely, if soil buildup causes the head to protrude, the surrounding grade may need adjustment to prevent the head from being struck.
Installing protective rings, often made of plastic or concrete, around the head can also mitigate damage. These rings act as a permanent, rigid barrier that the string trimmer can safely contact, shielding the head inside. Routinely clearing the area of aggressive runners, such as Bermuda or Zoysia grass, prevents the turf from growing over and seizing the pop-up mechanism.