Which of the following is a reason that increasing the mowing height can improve the energy efficiency of a lawn?

• A. Taller grass shades the soil surface, keeping it cooler and reducing water use.
• B. More weed competition.
• C. Increased clipping volume.
• D. Longer mowing time.

Answer: (A)

Raising mowing height improves energy efficiency by changing how the turf interacts with its environment. When grass is taller, the blades form a denser canopy that shades the soil, keeping surface temperatures cooler. This shade reduces soil evaporation and the amount of water the lawn needs, which in turn lowers the energy required to pump and apply water for irrigation. In other words, the lawn uses less energy overall to stay hydrated and healthy because it relies less on cooling through transpiration and irrigation.

Choosing a taller cut also means the grass can recover more gradually and maintain vigor with less frequent mowing, whereas shorter cuts typically require more frequent mowing and can increase overall maintenance energy. The other ideas—more weed competition, more clippings, or longer mowing time—tend to increase inputs or stress the system, making the lawn less energy-efficient.