Dog Days, The Reason Why, and Demonstration!

Hello and welcome to "The Greenkeeper"!  Today is Thursday, July 3rd, the eve of Independence Day, but it is also the beginning of Dog Days (traditionally the hottest, most sultry time of summer).  For those of you unfamiliar here is a portion from one of my posts in 2012: Most everyone has heard the term "dog days of summer" and knows they occur during the hottest and muggiest part of the season.  In our latitude that period typically occurs for approximately 40 days beginning around July 3rd and wrapping up around August 11th.  The term comes from the ancient Romans who recognized the star Sirius, also known as the dog star because it is the brightest star in the constellation Canis Major (large dog).  In late July Sirius will rise and set in conjunction with the sun.

Canis Major

The Romans named the period for 20 days before and 20 days after this conjunction "dog days" after the dog star.  The Romans actually thought Sirius gave off heat due to the star's brightness and this heat, in addition to the sun, was the cause for the extremely hot weather associated with the dog days.  
If you have been out to enjoy the course the past couple of days you probably thought the dog days had started already.  Yesterday was our warmest day of 2014 as we topped out at 95 F, and we actually reached 90 F or above ten times during the month of June (reaching 93 F on two occasions).  The golf course hardly shows any lingering effects from a cold winter that is now a distant memory.  You probably also noticed a discernible decrease in putting green speed.  This is by design.  Not to say I intentionally slowed the greens, but we are managing our bentgrass greens for summer survival and slower green speed is the side effect.  Let me explain (warning, not a short explanation)

Our putting greens are a blend of A1 and A4 creeping bentgrasses.  These are cool-season grasses meaning they prefer a cooler, less humid climate for ideal growth (this is why our greens are so good from September through June).  Bermudagrass on the other hand is a warm-season grass meaning it prefers warm, humid conditions in order to thrive (this is why our tees, fairways, and roughs are always in peak condition this time of year).  When temperatures climb into the upper 80's and 90's F consistently, soil temperatures begin to rise.  During extremely hot summer months soil temperatures reach levels fatal to bentgrass roots.  In fact, creeping bentgrass can lose up to 75% of its total root mass during summer.  

In order to survive warm temperatures, bentgrass turf cools itself through a process called transpiration.  The plant takes up moisture through the roots, moves the moisture up through the plant tissue, then the moisture exits the plant through leaf openings called stomata where it evaporates.  To further understand this concept think about how we humans perspire to keep our body temperatures from overheating during hot weather.  Now also think about how well perspiration works on us humans when it is very humid outside (not comfortable). This is why fans are so critical to bentgrass putting green health in our climate.  When there is no air movement around a green, the moisture exiting the plant via transpiration cannot evaporate (kind of like sweat sticking to your skin). The air flow over the putting surface provided by the fan allows the natural process of transpiration to work more effectively.

Now, the fact plants can cool themselves via transpiration is great, but there is more.  It takes energy to run the plant's natural metabolic processes and that energy comes from carbohydrates.  We all know plants produce their own energy via photosynthesis, but did you know in extreme conditions turfgrass plants will close their stomates to prevent extreme moisture loss.  When this happens the plant enters into a process called photorespiration.  I think this is a good place to cease with the science and just get to the point...  

Not bad for July 1st!

The reason why bentgrass greens are slower in the summer is because we mow the greens at a higher height of cut this time of year.  We do this in order to assist the plant with its ability to photosynthesize.  Right now bentgrass consumes more energy than it produces.  This energy deficit leads to a "decline" in overall turf quality.  This decline can be characterized by a number of things including loss of vigor, thinning, and disease susceptibility, thus we must manage the greens right now with the utmost TLC.  We hand syringe greens during the day to help keep the canopy cool (please do NOT hit onto the putting greens when I or one of my staff members is syringing, unless we wave you through).  Also, we are treating greens weekly with foliar fertilizers and other plant protectants to bolster their immune systems and help them produce energy.  In order for the plant to produce energy via photosynthesis, the plant needs leaf tissue to capture the sun's energy.  The more leaf tissue, the more surface area with which to capture the sun's energy and convert it into sugar (carbohydrates).  

Now mowing height alone is not the sole determining factor of putting green speed throughout the year, but it is the dominant reason right now, and thus the greens putt more like those of a sea-side links than what we are accustomed to during the spring and fall.  In my opinion you can either choose to have a poor mental attitude and dislike the slower speeds this time of year, or think about it positively.  It is a nice (short-term) break from having to putt so defensively, so putt confidently and without fear of running the ball too far past the hole.

Finally, one more thing you may have noticed recently.  We have removed most of the stakes and ropes from the golf course.  Now, this removal is not an open invitation to drive anywhere on the course.  On the contrary, we have been asking you for about a month now to only operate your carts in the fairways (if you are only in the fairways, there shouldn't be a need to rope off areas in the rough).  Besides, stakes and ropes are unsightly and the golf course looks much more attractive without them, but I still see some of you having trouble grasping the "fairways only" concept.  Our very own General Manager, Roger Wolfe was "testing" the course conditions the other day and I managed to capture him demonstrating how to play a shot from the rough while maintaining his cart in the fairway.

Roger Wolfe, CCM

You see, it really is very simple.  Help spread the word (#FairwaysOnly, #NoRoughs) and together we can make Carolina even better.  Hope everyone enjoys a happy and safe 4th of July... and no three-putts!

See you on the course,

Matthew Wharton, CGCS