Above-average temperatures finally arrived in the Northeast and they have been accompanied by below-average rainfall in the northern part of the region. Some areas have slipped into “Abnormally Dry” or “Moderate Drought” conditions according to the U.S. Drought Monitor. Cool-season turf is under some stress at most courses, and it is likely to get worse before it gets better.
Now is the time of year when the impact of mishaps and mistakes can be magnified. For example, a sprinkler that sticks on and floods an area in May usually doesn't cause significant problems. If a sprinkler sticks on in July or August when temperatures are high, the result can be wet wilt, scald or disease – all of which can lead to dead turf, poor playability and the need for a recovery program.
Many things are out of our control, so the key is to control what we can and avoid self-inflicted problems. Here are a few tips for success this summer:
Supervise The Hand Watering Team
Most courses hand water during stressful months to increase precision and avoid overwatering, but some staff seem to have a unique ability to get more water out of a hose than others. Too much water usually causes more problems than not enough water.
Make sure staff know when it's appropriate to water and when it isn't. Water alone won't cool turf very much or for very long, and adding moisture when humidity is elevated and there is little air movement is like throwing gasoline on a fire.
Don't Forget Your Fans
Fans can lower canopy temperatures by 6-8 degrees Fahrenheit or more. That can make the difference between life and death when soil temperatures are extreme. Specially designed fans for putting greens can work wonders, but they should be adjusted to oscillate inside the green margins to maximize their time over the turf. Even shop fans and blowers can help in a pinch. Just remember, non-oscillating fans must be moved regularly.
Dial Back Stressful Maintenance Activities
If your turf is under extreme stress, determine where and how much to dial back stressful maintenance activities. Measured responses to increasing stress levels will help you maintain reasonable playability while preserving turf health. For example:
- Postpone topdressing applications until favorable weather returns. Also, skip cultivation of all types unless excessive rainfall creates anaerobic soil conditions. Even a gentle venting operation causes some injury and it may damage weakened turf.
- Switch to solid rollers instead of grooved ones if you have aggressive putting green mowers.
- Raise mowing heights. Even a slight increase of 0.005-0.010 inch can help. Keep in mind that common putting green mowing heights are about the thickness of two dimes, so a 0.5-1.0 percent increase isn't much and won't have a significant impact on playability.
- Alternate between mowing and rolling. Have staff avoid mowing or rolling areas of weak turf such as putting green perimeters or expansion areas. As stress levels increase, skip both mowing and rolling.
- Adjust growth regulator application intervals based on their metabolization rate and determine if application rates should be adjusted. The GreenKeeper app is a helpful tool for determining growth regulation application intervals.
If Thinning Occurs, Consider Plugging Affected Areas
As turf thins, cutting heights are effectively lowered since there is less turf canopy to support the mower. Installing 3-inch or 4.25-inch plugs spaced a couple of inches apart can help maintain the desired height, thereby protecting injured turf. Hopefully turf from the plugs will spread as well.
Stressful summer months are a time when doing more can cause more problems than doing less. Discretion is the better part of valor during this time of year and knowing when to take your foot off the gas is part science and part art. Ultimately, decisions should be evaluated based on their potential risk and reward. Keeping green speeds a few inches faster is risky during certain times of year. Taking risks now can come with the downside of damaged turf, poor playing conditions and a lengthy recovery period.
Northeast Region Agronomists:
David A. Oatis, regional director – doatis@usga.org
Adam Moeller, director, Green Section Education – amoeller@usga.org
James E. Skorulski, agronomist – jskorulski@usga.org
Elliott Dowling, agronomist – edowling@usga.org
Paul Jacobs, agronomist – pjacobs@usga.org
Information on the USGA’s Course Consulting Service
