Bentgrass Greens in the Hot, Humid Southeast!

July is here and so are the temperatures we have become accustom to in Central North Carolina.  90 Degrees or more are almost a daily occurrence and the humidity is often the cause of afternoon thunderstorms.  The summer temperatures are great for outdoor activities and vacations, however they can cause serious issues with Bentgrass greens on golf courses.

The greens at Greensboro Country Club are creeping Bentgrass, Agrostis stolonifera.  More specifically, the Bentgrass on the Farm course is a blended variety called Penn A-1/A-4.  The Irving Park course is a variety called Cato.  Bentgrass is what is known as a cool season turf, meaning that it grows best in temperatures of 65-80 degrees.  The A-1/A-4 variety on the Farm course is an improved variety over the Cato variety on the Irving Park course.  While both are improvements over the old Penncross variety that use to dominate the region both still require many cultural practices in order to keep them healthy and thriving. 

During the summer months the maintenance staff at Greensboro CC will spend countless hours "watching" greens in the afternoons during these hot days.  Our assistants spend their afternoons looping the golf course looking for any signs of stress or wilt (wilting turfgrass shows up as purple in color).  If the temperatures are extremely high we will often mist the greens down to use the evaporative cooling of the water to lower the temperature on the surface. "Watching" greens is the final cultural practice to keep greens alive through the summer heat.  There is much more that is done before the heat of the day to help reduce the possibility of wilt.  Our crew inspects each green every morning and takes moisture readings on a digital soil moisture meter as well as pulling cores to get a visual image of what is happening to the roots.  The assistants will pay close attention to areas that are chronically the first ones to show summer stress.

Solid Tine Venting

There are numerous additional practices that must take place once the heat sets in to help ensure survival of the greens.  Flushing the greens every 2-4 weeks is a practice we use to remove unwanted soluble salt buildup in the soil and to uniformly wet the entire soil profile from top to bottom.  The frequency of this heavy watering practice is often dictated by weather.  The hotter the weather the more frequently we will flush.  We also occasionally vent the surface of the greens with a small solid tine aerification.  Dead plant material in the upper portion of the soil profile is very common on Bentgrass this time of the year and the decaying plant material will eventually seal off the upper portion of the soil profile.  This resulting unwanted organic accumulation allows the buildup of carbon dioxide and hydrogen sulfide, which will lead to a very toxic growing environment if not managed properly.  Small tine aerification helps with the infusion of higher levels of Oxygen into the critical rootzone to combat the natural growth cycle of a highly maintained cool season grass that is growing in a region of the world where it is not fully adapted.  

Syringing / Misting