Out of the Oven and Into the Fire

August 11, 2011

This article comes to us from Ty McClellan, USGA Green Section Record Mid-Continent Region Agronomist. Ty provides his thoughts about the hot temperatures most have experienced this summer and the toll is has taken on cool-season grasses.

Although the summer of 2010 was one of the hottest on record and widely publicized for the wake of destruction in the turf industry, it looks as though we’ve jumped out of the oven and right into the fire in 2011. Popular phrases that include ‘the perfect storm’, ‘equal opportunity destroyer’, and ‘turf loss of epic proportions’ are being bantered about once again, as Mother Nature turns up the heat and tries to roast the cool-season turfgrasses found on many golf courses beyond well done.

Managing turf during June and July in the upper Mid-Continent Region has been anything but easy, given the persistent heat wave. For much of Kansas and Missouri, nearly every other day during the past nine weeks has exceeded 100°F, and nighttime lows have rarely dropped below 80°F. Even though it is hard to imagine, 2011 may surpass 2010 for record heat. Some superintendents are already stretched, as this summer has dealt them an even worse set of circumstances. August conditions may leave some to wonder how they will have any turf to manage as putting green soil temperatures may continue to exceed 90 degrees.

Somewhat surprisingly, education and communication efforts that were effective last year are not providing the same understanding ears this year. Course officials and golfers seem to be less receptive to the news about heat stress. This is a good time to revisit some fundamental principles of turf management:

Creeping bentgrass root dieback begins when soil temperatures exceed 86°F at a 2-inch depth.

Poa annua is a fragile species that is usually the first to decline during high temperatures.

Portions of putting greens that suffer from poor air movement, poor drainage, and concentrated traffic (particularly the collars) are the most difficult to maintain and the first to decline.

To survive the heat and maintain turf health until the fire is extinguished with the onset of cooler temperatures, some of the most effective strategies include:

Supplement automatic irrigation as much as possible with hand watering.

Raise the mowing height and use solid front rollers when preparing the greens for play.

Mow less frequently and roll instead.

Use large oscillating fans to improve air circulation and assist the transpirational cooling of the turf. The fans may be needed continuously for 24 hours of the day.

Vent the greens when possible via non-disruptive aeration techniques.

Increase the rate and frequency of fungicide applications, as disease pressure increases with higher temperatures.

Reduce traffic on the putting greens via temporary closure, if necessary, or cancelling / rescheduling large outings.

Cool-season turfgrasses are in a fragile state, and superintendents and their staffs are feeling the effects of long hours and touch-and-go conditions. Now is the time to support them as they work to maintain the turf. Expectations for exceptional playability simply must be put on hold until temperatures cool off…and hopefully that is soon.

If you would like more information about a Turf Advisory Service visit, do not hesitate to contact either of the Mid-Continent regional offices: Ty McClellan at tmcclellan@usga.org or (630) 340-5853 or Bud White at budwhite@usga.org or (972) 662-1138.