By the time August arrives, ultradwarf bermudagrass putting greens are in full seasonal stride. Growth has been steady and at times aggressive, fueled by warm nights and long days. Yet across the Southeast, this is also the time when an unwelcome late-summer visitor often appears: scalping during mowing. Here’s a quick look at why it happens and ways to mitigate the problem.
Why Scalping Happens in Late Summer
Scalping occurs when the mower cuts deeper than intended, removing the entire leaf blade and exposing stems or stolons below. On ultradwarf bermudagrass greens, this is often the result of surface irregularities that develop over time. Throughout the summer, rapid growth, thatch accumulation and grain formation cause certain areas of the canopy to sit slightly higher than others.
This “puffiness” is especially noticeable when topdressing, verticutting and grooming have not been able to keep pace with growth. Add in the natural tendency of ultradwarf bermudagrass to develop grain and you end up with an uneven surface. When a mower rides over these raised spots, even if the bench setting is correct, the cutting unit drops into the canopy and removes more tissue than desired. The result is a light tan or brown patch that can affect appearance and ball roll.
The Challenges of August
August often creates a perfect storm for scalping ultradwarf bermudagrass greens. Turf is still actively growing, yet it’s also under significant stress from high temperatures, humidity, frequent rainfall, heavy play and other sources. After a long season, carbohydrate reserves are generally depleted in warm-season grasses, slowing the plant’s ability to recover from injury. The final aeration of the summer can add to the challenge. Extra fertilizer is often applied to speed recovery, but this surge in growth, combined with softer surface conditions, can make it challenging to achieve a clean and even cut until the greens have firmed back up.
During this period, granular nitrogen (N) applications should be limited to no more than 0.5 pounds per 1,000 square feet at a time, with individual liquid applications kept around 0.1 pounds per 1,000 square feet to prevent excessive growth. Depending on traffic and current growing conditions, try to keep the total amount of N for August and September to no more than 1.5 pounds per 1,000 square feet between all applications. This is an ideal time of the year to increase intake of potassium and other essential micronutrients. Pair conservative nutrient inputs with consistent use of plant growth regulators to maintain a steady, controlled growth rate. Finally, exercise caution when using aggressive surface management techniques – particularly verticutting with carbide blades – during late-season cultural work.
Scalping Prevention
Preventing scalping is less about a single corrective action and more about consistent surface management throughout the year. The most effective programs typically include:
Light, Frequent Topdressing: Applying small amounts of sand regularly helps dilute organic matter, maintain a smooth surface and keeps the mower riding evenly.
Grain and Puffiness Control: Grooming, brushing or light verticutting encourages leaves to stand upright, reducing canopy unevenness.
Height-of-Cut Adjustments: Raising mowing height slightly during peak summer stress can increase energy production in the plant and help preserve surface quality without significantly affecting green speed.
Firmness Through Moisture Management: Avoiding overly soft greens helps keep mowers from sinking into the turf and making uneven cuts.
Equipment Adjustments: Consider making the change from grooved front rollers on mowers to smooth rollers to take the pressure off the surface and to help even out the cut for smoother putting greens.
Southeast Region Agronomists:
Jordan Booth, Ph.D., senior director, USGA Course Consulting Service – jbooth@usga.org
Chris Hartwiger, director, Agronomy – chartwiger@usga.org
Chris Neff, agronomist – cneff@usga.org
Mitch Leininger, agronomist - mleininger@usga.org