Mowing over dog waste on your lawn is strongly discouraged. Skipping cleanup before mowing introduces problems that affect the health of your family, pets, lawn, and equipment. This practice transforms a localized issue into a widespread contaminant risk, requiring a thorough pre-mow inspection and removal.
Mechanical Consequences for Equipment
Striking dog waste with a high-speed mower blade transforms the material into a sticky, pulverized substance that coats the underside of the equipment. This residue quickly clogs the mowing deck, impeding the flow of grass clippings and reducing cutting performance. A fouled deck requires more power to operate, placing strain on the engine and potentially leading to overheating or premature wear.
Cleaning the machine is unavoidable once the deck is coated. The acidic nature of dog feces accelerates corrosion on the mower’s internal components, especially the blades and deck housing. Repeated exposure to this waste also dulls the cutting edge faster, requiring more frequent sharpening or replacement.
Spreading Pathogens and Health Hazards
Dog feces is a biological hazard, containing numerous pathogens and parasites that pose a risk to humans and other pets. When the mower blade hits the waste, the material is aerosolized, finely pulverizing it and propelling it across the turf in a wide radius. This process turns the localized waste into an invisible spray of contaminants, spreading bacteria and parasitic eggs far beyond the original deposit site.
The spread includes bacteria such as E. coli and Salmonella, which can cause severe gastrointestinal distress. More concerning are parasitic eggs, like those of roundworms (Toxocara canis) and hookworms, which are microscopic and can survive in the soil for months or years. Mowing disperses these eggs, making the entire lawn a source of infection that can be tracked into the home on shoes, paws, or play equipment. Zoonotic transmission, the spread from animals to humans, is a serious public health concern. Children are at high risk because they are more likely to ingest contaminants while playing on the grass or soil.
Effects on Turf Quality and Aesthetics
The high concentration of nitrogen in dog waste can severely damage the grass beneath it. This effect, often termed “lawn burn,” occurs because the nitrogen acts like an overdose of fertilizer, scorching the grass blades and killing the roots. When the mower pulverizes the waste, it creates a trail of this high-nitrogen material, leading to scattered patches of damaged or dead turf across a much larger area.
Mowing over feces introduces an obvious aesthetic issue that is difficult to correct. The pulverized waste is scattered and pressed down into the grass, resulting in an unpleasant, unevenly distributed residue that is harder to remove. Dog waste can also contain fungal spores or weed seeds, which, when spread by the mower, promote the growth of unwanted organisms across the lawn.
Safe and Effective Cleanup Protocols
The most effective way to prevent negative consequences is to ensure the lawn is clear before starting the mower. Cleanup begins with immediate removal of the waste using a scooper or an inverted plastic bag, which should be sealed and disposed of in a designated trash receptacle. Pet waste should not be placed in backyard compost piles because typical home composting temperatures are insufficient to destroy dangerous pathogens like roundworm eggs. If waste has been sitting and left residue, a simple hosing down with water can help dilute any remaining material and wash it deeper into the soil. Establishing a routine of daily or every-other-day waste removal keeps the lawn clean and minimizes risk to both your equipment and the people who use the yard.