“…And The Fans Went Wild!”
By David A. Oatis, director, Northeast RegionJuly 19, 2012
At many courses, a distinct pattern is starting to become all too prevalent. Greens with restricted air movement across their surfaces invariably have the weakest turf found on the course. This sometimes painfully illustrates the impact poor growing environments can have on turf performance. This is another season where the value of fans is being demonstrated in numerous locations. Fans cool turf and dry it out. Using an infrared thermometers, USGA agronomists consistently find that turf canopies receiving the additional airflow provided by fans are 6-8° F cooler than adjacent turf outside the range of the fans.
Virtually all of the annual bluegrass turf we have observed in the last two weeks has been under stress. Root systems have shrunk so dramatically that it is becoming hard to find annual bluegrass root systems that are more than an inch deep. In addition to being shorter, root systems may also be impaired by various fungi and nematodes. In a nutshell, the annual bluegrass putting green turf at some courses is teetering on the brink of failure and this next heat wave may push some over the edge.
So what should we do to avoid turf loss now?
- Improve air movement. Fans can help tremendously. They can make the difference between life and death to the turfgrass plant. Normally, they work best when used preventively (before the turf goes under stress) but they also can help curatively so don’t hesitate to put them to use.
- There is a time to be aggressive with certain maintenance practices, but this is not it. While venting can improve drainage and gas exchange, aggressive cultivation is unwise in most situations at this point in the season. Cultivation techniques can injure root systems and the turf does not need any additional root system injury at this point in the season.
- Remember, while annual bluegrass greens may look terrible now but they can still play well. “Looks bad but plays fine” is a quote to keep in mind. Patience and emphasizing playing quality over appearance is the key to summers like this one.
- For now, seeding is not likely to be all that effective. But, if you want to try it use gentle seeding techniques so as not to injure the turf or damage the thatch layer.
- Being too aggressive now may weaken the turf and push it over the edge. It may also make it impossible to be more aggressive in 2-3 weeks when there is a much better chance of getting seed up and established. Again, patience now will be rewarded later.
- Plugging bentgrass into weakened areas makes more sense now. Two inch pluggers work very well for this purpose. Smaller plugs are less obvious and less objectionable than traditional 4.25 inch plugs. They are easier to level and can be put in much faster too.
- Stick with your growth regulator program and keep spoon-feeding. Be extremely cautious when applying these and all materials at this time of year. An improper rate or inadvertent overlap can cause more damage to stress-weakened turf.
- Manage water more carefully than ever utilizing your best employees for this crucial job. Remember, if the root systems are one inch deep, water at the two inch depth is unreachable. Syringe more but try to keep soil moisture levels lower.
- 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.”
- Depending on the degree of turf decline and the amount of annual bluegrass you have, this year may provide an opportunity to get more bentgrass established in your greens. Aggressive seeding this fall followed by closing the greens for a few weeks to give the seedlings a fighting chance may be worthwhile in the long run.
- Lastly, watch out for the combination of a high sky and low humidity day. With weak turf and weaker root systems, this is a weather pattern that could wreak havoc. Normal syringing techniques may not be sufficient if we experience this type of weather so be prepared should this occur.
- Don’t forget your employees. The weather is just as hot and potentially dangerous for them as it is for your turf. Make sure they stay hydrated and are allowed to rest and cool off during periods of extreme heat.
Another consistent observation we have made this summer is that bentgrass on greens throughout the region is tolerating the heat much better than annual bluegrass. The advantage of having bentgrass, particularly the new varieties, has never been more obvious. One has to question how long we can continue to manage annual bluegrass greens should these weather patterns continue. This is shaping up to be the type of year that will push more courses to consider a change.
USGA agronomists have been extremely busy but we are never too busy to hear from you so don’t hesitate to give us a call. We wish you all the best of luck for a successful season.
Source: Northeast Region Green Section - Dave Oatis, director firstname.lastname@example.org, Adam Moeller, agronomist email@example.com, and Jim Skorulski, senior agronomist firstname.lastname@example.org.