Date: May 2009
About: Alex Hultz - Class of 1987
Putting greens constitute a small percentage of the golf course, but they demand major attention from the golf-course superintendent. To provide faster and truer putting surfaces, superintendents often opt to topdress. This process, which involves adding sand or peat to the greens, once disrupted play and gummed up equipment. These days, however, topdressing is faster, easier and more convenient for all.
Topdressing helps accomplish several objectives beyond just smoothing the putting surfaces, though. It helps to control thatch, modifies the surface soil, aids in renovating and overseeding, and helps to protect greens in winter.
An effective topdressing program has three primary requirements: 1) selecting the proper topdressing material; 2) determining the appropriate rate of application; and 3) adjusting the frequency of topdressing to site conditions.
Ultimately, a properly implemented topdressing program will lead to healthier turf and better-quality greens. And while there is almost universal agreement about the benefits of topdressing, there is not a universal program that is appropriate for all courses.
How Much and How Often
Not long ago, topdressing was known only as a messy affair that involved aerifying greens by punching holes into them, dropping and dragging a thick layer of sand and amendments to fill the holes, sweeping off the excess, and then watering in what was left. Any golfer who has stepped onto a green after aerating knows they have a perfect excuse for missing that long putt. Aeration and heavy topdressing is still critical in the spring, and often in the fall as well, but superintendents can lightly topdress year-round for added benefits.
“In spring, we aerify the greens and then do heavy topdressing to fill in holes,” says Gordon Seliga, Certified Golf Course Superintendent at Lake View Country Club, North East, Pa. Gordon has perfected the topdressing program for the Poa annua push-up greens at Lake View for the past 23 years. “Throughout the summer months we go out weekly with a light topdressing,” he says. “In the fall, we core-aerify and then heavy-topdress. Then we light-topdress again until the snow flies.”
Lake Valley Golf & Country Club’s new spreader saves man hours and allows Superintendent Alex Hurtz to topdress very lightly.
Light topdressing (applying 2 to 3 cubic feet of material per 1,000 square feet every seven to 21 days) provides many of the same benefits as heavy topdressing, but without the inconvenience to golfers. In fact, afternoon golfers may not even realize the greens were topdressed that morning.
Alex Hultz, Superintendent at Lake Valley Golf & Country Club near Camdenton, Mo., uses 20 to 25 tons of sand on his three acres of bentgrass greens after aerification in the spring, but only 10 to 15 tons of sand for light topdressing every three weeks.
The amount of light topdressing depends on turf growth and thatch accumulation. As a general rule, that means bentgrass greens would require more topdressing, because bentgrass grows more aggressively than Poa annua. The fertility program also comes into play, says Seliga, because more growth equals more thatch potential.
“How often to topdress also depends on how short you cut your grass,” Hultz says. “At Lake Valley, we topdress heavy enough to get the benefits, and light enough that golfers aren’t affected.”
Robert Hertzing, Golf Course Superintendent at Valencia Country Club, Valencia, Calif., agrees with Hultz’s toe-the-line approach. “Topdressing is a commitment,” he says. “You have to work through some issues to get the right method for your course and players.”
Once a topdressing program is started, a key is to be consistent with both materials and the amount applied. Applying too much will cause layering, which can actually increase thatch buildup. Too much can also damage grass, due to the abrasiveness of the material being applied.
“If you’re consistent with topdressing, you’ll avoid that layering problem,” Hultz says.
Finding the Right Matches
For native-soil greens, topdressing soil should match the original soil as closely as possible, especially if the green is performing well. But because it can be difficult to locate consistent and adequate quantities of topdressing soil that offer the right match, some courses prefer to use a mix that is sandier than the native soil. This has become an even more acceptable practice because nearly all greens built today are created with sand (or a mix of sands) with a small fraction of organic matter—most commonly, peat.
“I used peat years ago,” says Seliga. “If you go back 15 years or so, a lot of people were using an 80-20 mix of sand and peat. I noticed on our course, though, that we were just burying thatch with that mix. I was actually criticized by peers at the time when we went to straight sand. They thought I would dry out the greens, but that’s not the case. I’ve been using straight sand for more than 15 years.”
But all sand is not created equal. Sands can be purchased in many different sizes and shapes. Seliga says angular sand is OK to use, but he recommends getting the coarsest sand that won’t cause a mowing problem. Hultz, on the other hand, recommends using round sand.
“Angular sands tend to pack a little tighter,” he says. “Round grains of sand let grass grow up between them. “
Hultz uses the same topdressing sand in his bunkers because he doesn’t want bunker sand, which is usually very fine, to be thrown up onto his greens by golfers blasting out of the sand traps.
“It’s best to take topdressing cues from the green’s soil,” he says, “and use sand that is similar or slightly more coarse.” Other important factors to investigate include cost, consistency and long-term availability.
Before purchasing a spreader, Hultz used a tow-behind drop spreader with a narrower swath that took more passes to topdress per green.
The Application Process
Equipment manufacturers have made great strides in building machines that can evenly apply a thin layer of topdressing over a large swath of green.
Two years ago, after trying out equipment from a number of manufacturers, Hultz purchased a spinner spreader, to replace the drop spreader he had been using previously.
“The new spreader has a computer with dials to adjust the speed of the conveyor belt and the speed of the spinners,” Hultz says. “Generally on my greens, I can topdress a green in two roughly 40-foot-wide passes.”
In the past, Hultz used a tow-behind drop spreader (see photo, above). But, because the drop spreader was only capable of applying a narrow swath of material, each green required six to nine passes. It was also a two-man job, with a crew member following the topdresser to fill the hopper when it got low.
“Topdressing is considerably faster now that I can spread further and refill on my own,” Hultz says. “I can zip out there and topdress in about two hours.”
Every course is different, however. Finding the right equipment to match a particular set of course conditions and budgetary and quality requirements can be a challenge. For one thing, not all courses can store sand indoors, to keep it dry enough to use in a broadcast spreader.
“For our light topdressing, we apply it with a walk-behind fertilizer spreader,” says Hertzing. “The manual method allows for a more even distribution, and we hit a couple of our trouble spots twice on occasion. It takes about nine man-hours for us to topdress.”
But no matter how you apply it, a season-long light topdressing program creates healthier, more consistent greens.
“Topdressing not only smooths the surface of greens and helps to manage thatch, it also increases the oxygen exchange at the surface, which helps drying and decreases disease potential,” says Hultz. “Thatch is a big issue. Disease potential and insects can be more problematic with a lot of thatch.”
Superintendents and general managers should place as much emphasis on selecting topdressing material and implementing a topdressing program for greens as they do on selecting the soil mix and constructing and establishing new greens. In both cases, you are creating the soil for the future. And once it’s in place, you can’t easily remove it. That’s why, as Hultz notes, the old adage, “Do it right the first time,” is especially appropriate for topdressing. C&RB
Many experienced golfers dread the word “topdressing,” because they equate it with the heavy applications that can disrupt play. Superintendents can allay these fears by explaining the benefits of topdressing and keeping members up to date on their course’s topdressing schedule.
A great way to do that is via the Web. Both Gordon Seliga, Certified Golf Course Superintendent at Lake View Country Club and Robert Hertzing, Golf Course Superintendent at Valencia Country Club, have blogs they update frequently to let golfers know when topdressing will take place and why it must be done.
“I communicate on my blog or send e-mails out and use our newsletter to let members know about our topdressing plans,” says Seliga. “I’ve used the blog to show pictures of aerifier holes with roots through them, to show them how important it is to aerate and topdress.”
Alex Hultz, Superintendent at Lake Valley Golf & Country Club, also uses the immediacy of the Internet to communicate the value of routine topdressing. Hultz has a topdressing page that describes the process with pictures and videos. He also has pictures and videos of the club’s new spreader, as well as its old drop-spreader, in action.
All three superintendents recommend topdressing during times when play is slow, to minimize disruption. But, given the right communication, golfers and Board members are generally understanding.