Extended periods of hot, wet weather often spell trouble for cool-season turf. Putting green collars and the perimeter cut of turf inside the collar, often called the cleanup pass, tend to thin out first along with any recent putting green expansions. In fact, significant turf loss where collars have been converted to putting surface within the past two to three years has been a topic of considerable discussion during many recent Course Consulting Service visits.
Why does turf in the middle of the green sometimes thrive when perimeter turf struggles to survive? Here are a few explanations:
- Stress to collar turf occurs when a roller stops abruptly or spins as it changes direction.
- Stress to collars and cleanup passes occurs where putting green mowers turn and spin before making another pass across the green. Double-cutting causes twice the injury.
- Wear and bruising to turf in a cleanup pass can be exacerbated by the constant use of grooved front rollers.
- Compaction and wear caused by the repeated tracking of triplex tires across the same turf in a clean-up pass.
- Inconsistent irrigation coverage along the perimeters of putting greens due to sprinkler limitations or poor irrigation design will weaken turf. Collar turf can be plagued by wet and dry spots, even around the same putting green.
- Bunker sand blasted onto a putting surface is double trouble. Golfers and maintenance equipment traveling across greens will grind the sand into the turf. The constant accumulation of sand on collars and perimeter turf adjacent high-use bunkers will also increase dryness in those areas.
- Golfer traffic and placing golf bags or parking pull carts on collars will also stress turf.
An ounce of prevention is worth a pound of cure during a stretch of hot, rainy weather. Consider these commonsense maintenance practices to keep the entire putting surface happy and healthy throughout summer:
- Check irrigation coverage and adjust nozzles to ensure uniform water application across putting green perimeters. Depend more on hand watering than automatic irrigation to manage turf during stressful weather.
- Alternate mowing and rolling to reduce mechanical stress to turf.
- Use mowers equipped with solid front rollers versus grooved rollers during hot weather.
- Keep rollers on the putting surface only and do not roll collars or the turf in a cleanup pass.
- Mow perimeters with a lightweight walk-behind mower instead of a triplex mower if possible.
- Use a dedicated mower for cleanup passes and slightly raise the mowing height.
- Vent greens with small-diameter solid tines as often as once per week during extended periods of hot, wet weather to maintain a healthy balance of air and water in the upper soil profile.
- Avoid heavy topdressing applications that require aggressive brushing to work sand into putting green turf.
- Small amounts of dry sand topdressing applied to putting greens with push spreaders can be useful to manage algae growth in areas of thin turf. Rates should be light enough for the sand to be worked into the turf canopy with irrigation or a lightweight cocoa mat.
- Suspend aggressive maintenance practices such as grooming, verticutting and double-cutting.
- Be extra vigilant for symptoms of damage from golfer traffic and use appropriate ropes, stakes and signage to divert foot traffic away from thin, weak turf.
On a final note, don't be afraid to raise the mowing height across putting green extensions that begin to thin out in response to hot, wet weather. Many extensions were once collars that were simply scalped down to putting green height, and it often takes four to five years before collar turf fully acclimates to a lower height of cut. Golfers will agree that an extra-wide collar looks and plays much better than a dead strip of turf.
Central Region Agronomists:
Bob Vavrek, regional director – firstname.lastname@example.org
John Daniels, agronomist – email@example.com
Zach Nicoludis, agronomist – firstname.lastname@example.org