USGA Article

Summer Heat Wave Facts
By Patrick O’Brien and Chris Hartwiger, Agronomists, Southeast Region
August 11, 2010

The summer of 2010 will be long remembered for its impact on bentgrass putting greens in the Southeast Region.
This summer produced many historical records for heat in the Southeast Region, and the result has been a nightmare for many bentgrass putting greens. The sad news is that probably another month of high temperatures is still ahead of us before cooler temperatures arrive.

Weather data compiled from the Georgia Automated Environmental Monitoring Network (www.georgiaweather.net) at the Atlanta Athletic Club, near Duluth, GA, reveals information that testifies to the extreme heat in the Southeast Region this summer. Mr. Ken Magnum, Director of Golf Course and Grounds at the Atlanta Athletic Club, passed along this information to our office earlier this week.

From June 8th to August 8th, a total of 645 hours had temperatures above 90 degrees. The average number of hours above 90 degrees over the past 12 years has been about 233. This is an increase of about 275% from the average. Even after sunset on many days, temperatures remained above 90 degrees and provided no time for the soil to cool down.

Hours 90 Degrees or Higher -Last 60 Days:

8-Jun 8-Aug Total

2010 2010 645
2009 2009 139
2008 2008 213
2007 2007 238
2006 2006 571
2005 2005 84
2004 2004 66
2003 2003 8
2002 2002 231
2001 2001 8
2000 2000 248
1999 1999 347

This extended heat wave created an almost impossible situation at most golf courses, making it very difficult for superintendents to manage their bentgrass putting greens. Additionally, many golf courses were faced with operational budget cuts again this year. Fighting the heat with fewer fungicides, equipment, and labor at these courses further added to the challenge.

Last week, the Carolinas GCSA conducted a special 48-hour survey of superintendents managing bentgrass and found the following:

•A full 84 percent say their greens are “thinning” or “severely stressed” right now
•Nearly 30 percent have had to close greens or expect to do so soon because of heat stress
•Less than a third of superintendents say they are “optimistic” about nursing their greens through the end of summer
•95 percent describe this summer as “the worst” or “one of the worst” they have ever seen for managing bentgrass.

If your golf course has bentgrass putting greens that have declined, you are not alone. Superintendents are poised to do everything possible to restore the health of their bentgrass putting greens when temperatures cool down again this fall.