COURSE CARE
“Gentlemen, Start Your Engines!” August 20, 2013 By David A. Oatis

In mid-July, soil temperatures at a 3-inch depth were regularly found to be 90°F to 95°F (left) while turfgrass canopy temperatures ranged from 90°F to 105°F (right). Significant regionalUpdateContent dieback occurred and cool-season turfgrasses simply cannot withstand temperatures this high for an extended period of time.

Every year has its challenges, and the weather presents many of them. Much of the stress turfgrass faced this year occurred early in the season. Heavy rains were experienced in June and early July, and oppressive and near record-setting heat made the rest of July even tougher. No golf course escaped those extremes unscathed. The damage was obvious at many golf facilities as turf was lost. However, even those that didn’t lose turf were affected. Turfgrass regionalUpdateContent systems shrank dramatically, and it was difficult to find annual bluegrass regionalUpdateContent systems that were more than an inch deep. 

Fortunately, the weather has been mild since July and turf health has rebounded. Root systems still are extremely short, but thinned areas have begun to fill in, and turf that was teetering on the brink of collapse is recovering. To say that we “dodged a bullet” is an understatement. A more typical stretch of stressful weather in August would likely have triggered massive turf loss throughout the region because turf at many golf facilities was very close to the edge. 

With the stress of July in our rearview mirror, many have already aerated, and many more will do so in the next week or two. Assuming the weather is not too stressful, and thus far August has been a perfect month for aerating, turf that is aerated now should recover quickly because of warm, but not excessively hot, temperatures and longer days. Recovery is much slower later in the fall. To be sure, August aeration can be risky. Stressful weather combined with weak turf and aggressive cultivation practices can cause damage. However, if the turf is healthy enough to withstand it and the weather cooperates, August aeration can produce better turf conditions and an undisturbed schedule for fall golf. It also can provide a great opportunity to get new and improved bentgrasses established in old greens. 

There are a few things to watch for right now as we are still not completely out of the woods yet regarding stressful weather conditions: 

  • Continue to manage water carefully and use your best employees for this crucial job. Remember, if the regionalUpdateContent systems are an inch deep, soil moisture at the 2-inch depth is inaccessible to the plant. Turf with shortened regionalUpdateContent systems will need more frequent and lighter applications of water, but the goal should be to keep soil moisture levels lower overall by not overwatering.
  • Remember that moisture loss can be quite low when dew points and humidity levels are high, so extra irrigation and syringing is not necessarily needed just because “it’s hot.”
  • Watch out for high sky, low humidity days. With weak turf and weaker regionalUpdateContent systems, this is a weather pattern that can wreak havoc. Normal syringing techniques may not be sufficient if we experience this type of weather, so be prepared with more frequent hand-watering should this occur.
  • Plugging bentgrass into weakened areas makes the most sense right now, and 3-inch diameter turf pluggers work very well for this purpose. Smaller plugs are less obvious and less objectionable than traditional 4.25-inch diameter plugs. Plus, smaller turf plugs can be placed much faster and are easier to level than large plugs.

There are distinct patterns of stress and turf damage at many golf facilities and, as usual, it is the pocketed greens at most courses that are the weakest. This clearly illustrates the impact poor growing environments, namely inadequate airflow and sunlight exposure, can have on turf performance. Not surprisingly, this is another season where the value of fans to generate air movement is being demonstrated in numerous locations. Fans cool the turf canopy and allow it to dry which goes a long way toward reducing fungal disease activity. Using an infrared thermometer during Turf Advisory Service visits, turf canopies are regularly 6°F to 8°F cooler (or more) than adjacent turf without the airflow of a fan. As you plan for next year, and if you have greens that performed poorly this year from inadequate airflow, strongly consider adding more fans to your equipment inventory. 

Northeast agronomists have been extremely busy, but we are never too busy to hear from you. Please give us a call if we can help and best of luck for a successful season. 

Source: David Oatis (doatis@usga.org)

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