Few things are as important to turfgrass as proper mowing. It is one of the most frequently performed cultural practices that has the ability to make an immediate impact on the beauty of a lawn, athletic field, or other turfgrass sites. When walking into a baseball, football, or soccer stadium and getting that first glimpse of the playing surface, what stands out the most? Is it the latest fertilizer application or irrigation cycle? The soil pH or particle size analysis? Probably not, but many fans would tell you it’s the intricate mowing patterns or field uniformity and consistency that hits them first.
Turfgrass is only turfgrass because it is mowed. With over 10,000 species of grasses in the world, only about 30-40 of them form dense turf when mowed. These species, which evolved under grazing from animals, create the fabric that is found in many urban landscapes, holding disturbed soils in place, capturing stormflow and rainwater, cooling our homes, creating fresh oxygen, and providing a safe place for kids and athletes to play. Perennial turfgrasses are one of the few species of plants that can tolerate mowing, and it is because of their adaptation to regular defoliation, aka grazing.
Turfgrasses have a recommended mowing height range that varies by species. For most home lawns, these height ranges vary from 1 to 3.5 inches (2.5 cm to 8.9 cm). The frequency at which lawns require mowing typically increases as mowing height decreases. This is because it is important to not mow off more than 1/3rd of the leaf blade at any one time. Mowing frequency also depends on temperature, moisture, fertility, and any other factor impacting growth. Cool-season grasses (fescues, ryegrasses, bentgrasses, etc.) grow faster and require more mowing during the spring and fall months than the summer and winter months, while warm-season grasses (bermudagrass, zoysiagrass, St. Augustinegrass, etc.) require more frequent mowing in the summer months. As a result, it is important to adjust mowing frequency, and perhaps even height, with growth rate.
It is also important not to overlook the physiological impacts of mowing on turfgrass growth and health. While mowing is a good thing and necessary for turfgrass growth, any type of defoliation (mowing or grazing, for example) reduces the amount of leaf surface that serves as the photosynthetic apparatus for plants. Leaves, after all, capture sunlight to serve as energy for converting atmospheric carbon dioxide to sugars and carbohydrates for growth and storage in roots and stems. Mowing grasses too short or too frequently can reduce this capacity and be detrimental to plant health, especially during stressful periods. However, mowing too high results in turfgrass leaves that shade each other out which reduces lawn density and traffic tolerance.
This makes it important to find the balance of the proper mowing height and frequency that encourages lateral growth while also leaving enough leaf tissue in place to support photosynthesis. Other tips for healthy mowing include using sharp blades, not mowing when lawns are excessively wet or drought-stressed, and leaving behind clippings when possible, especially when using mulching kits. Finally, who doesn’t recognize the smell of fresh-cut grass? From the weekend warrior to professional athletic field manager, tips for proper mowing allows everyone to enjoy fresh natural grass.