The greens at The Hasentree Club are creeping bentgrass, agrostis stolonifera. More specifically, the bentgrass is a variety called Penn A-4. Bentgrass is what is known as a cool season turf, meaning that it grows best in temperatures of 65-80 degrees. The A-4 that we have at Hasentree is adapted to higher temperatures than many other varieties but still requires many cultural practices in order to keep it healthy and thriving.
During the summer months the maintenance staff at Hasentree 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.
There are numerous additional practices that must take place before the heat sets in, and often during heat spells, in order to help ensure our greens survival as well. For example, below is a snapshot of what our crew did this week before the long 4th of July weekend.
Monday June 30
Our crew took advantage of the golf course being closed to use solid tines and aerify the greens. The solid tines do not pull a core but rather open holes and channels in the surface. Air movement and the ability of the roots to breath is the single most important thing we can do to help the plants. These channels allow water and oxygen to more efficiently move into the rootzone. The channels will also allow carbon dioxide and hydrogen sulfide to be released from the soil. These gases, if left in the soil, would prove toxic to turfgrass roots.
Once the greens were aerified, we roll the green in order to smooth out the tufting that occurs with the solid tines. Most of the time, a golfer wouldn't even recognize that this had been done after the roll. Since we were closed, we then applied gypsum or calcium sulfate. The gypsum will bind chemically to the salts that accumulate in the soil during the summer months. The salts will become toxic as well to the roots if left alone.
We applied the gypsum knowing that we were going to "flush" the greens that night. "Flushing" is the act of applying a significant amount of water to the green in an attempt to fill the sand cavity that the greens are built in. Once there is enough water to fill the entire depth of the greens cavity, it creates enough pressure to allow the water to drain quickly out the bottom of the green through the drainage pipe. Once this happens it literally "flushes" and as it drains rapidly out of the green it also pulls the salts and other detrimental contaminants out with it. Additionally this "flush" evens up the water throughout the rootzone and allows for more even moisture.
Tuesday July 1
We begin the flush very early in the morning and it still takes until around 8:00am to finish all 22 greens. We are able to get the front nine greens done well before this time in order to stay ahead of play for the day. Once the flush is complete we allow the greens to drain and then roll them to smooth out any softness that may still be there.
Later in the day, we went out and applied 0-0-25, potassium. Potassium is an essential nutrient in the plant to strengthen cell walls and help the plant against the heat. Potassium is also very mobile in the soil and whatever potassium was left in the soil was "flushed" out of the green along with the all of the detrimental materials.
Wednesday July 2
This morning our assistants applied a product called "Turfscreen" to the greens along with some preventative fungicide. The Turfscreen is a pigment that also has the same products approved by the FDA for use in sunscreen for people, titanium dioxide and zinc oxide! The turfscreen does exactly what sunscreen does for people, it protects the leaf blades from the suns UVA and UVB rays by reflecting them. In studies that we performed two years ago, we noticed a noticeable reduction in the surface temperature of the green when using this product.
As you can see, a lot of careful attention and hard work goes into keeping the greens at The Hasentree Club in good condition and healthy. As mentioned above, this is just a quick snapshot of what we do. A lot of work throughout the year goes into maintaining bentgrass greens throughout the summer. From fall and spring core aerifications to a strong fertility program to help build roots, everything that is done is well thought out and has a purpose.