Mointoring Winter Soil Temperatures

 Since the winter of 2005 we have been monitoring the soil temperature under 3 of our greens covers, from the time the covers are installed in the fall until the covers are removed the following spring.  During the winter of 2004 we experienced significant dessication to our turf on the majority of our greens.  One of our biggest questions at that time was when did the winter kill occur?  We all know as long as it's winter and we have snow cover, there's nothing we can do if winter kill has taken place, but we figure it's sure better to know when and why it happened than to know nothing at all.      

Data Loggers are located on greens 6, 7 and 12

The installation of the Watchdog Data Logger is an easy device to utilize.  We can set the monitor to gather data from every minute to every 2 hours.  We gather data every 2 hours and it can store enough data to last 365 days.  The data logger is installed next to the green and two cables are installed under the cover.  One monitors soil temperature and one monitors the temperature between the cover and the green.  The data logger also gathers ambient air temperature.  Typically we will leave the monitor on the course all winter and unless there's some really unique weather patterns that may indicate to us the turf is in jeopardy, we have no real reason, besides curiosity, to bring the data loggers in to down load the information.

So today, out of curiosity and the fact that we have a Grounds Committee meeting this week, I wanted to look at the information and see where we stand at this point in the season.  After gathering this information for the past 6 years, one thing we have found to be very consistent, once the ground freezes and we have snow cover, no matter the warming of the air temperature, the soil has yet to get above 32 degrees until the snow is completely gone and the frost comes out of the ground.  Additionally once we have snow cover the fluctuation in soil temperatures is very minimal no matter how cold we get and no matter how warm it gets. 

It appears from the information gathered today, the above information continues to hold true.  This year we installed the covers on November 10th, the following day we had 8" of snow.  The ground never really froze.  We do not have a deep frost this year.  Since the soil temperatures were unable to freeze before the snow event, the snow has insulated the ground very well.  Interestingly the soil temperature under the covers has been consistently at 30.6 degrees and 31.4 degrees for the past 3 months. 

The coldest recorded air temperature was on January 21st, at -26.8 degrees.  Due to the insulation of the covers and the snow, soil temperatures remained at 31.4 degrees.  Then on February 13th we were having our mid-winter thaw, air temperatures reached a high of 49.6 degrees.  Soil temperatures remained at 30.6 degrees.

Past history has shown us that temperatures that remain steady and below freezing, our fine turf areas have emerged from winter in great condition.  What will happen this year has yet to be seen, we have a lot of snow remaining and a good 4-6 week to go before we will have a good answer.  But until that time, we know only what the data logger information is at this point. If anything was out of the ordinary, it would still remain out of our control.  Now the question remains, what kind of damage might we see from snow mold?