Superintendents reveal strategies to maintain cool-season grass in the mid-Atlantic, where the heat can get red hot

It’s May, and Maryland-based Golf Course Superintendent Mike Salvio knows what’s lurking down the calendar – the sizzling heat and stifling humidity of a mid-Atlantic summer, which makes this region one of the toughest places to do so in the country to grow cool-season grass.

How hot can get it get? Picture Godzilla walking the course on a July day spewing fire from his chops. But Salvio, the certified golf course superintendent at the 36-hole Ocean City Golf Club in Berlin, Md., isn’t sweating about the upcoming summer … well, not too much. That’s because he has learned how to tame the beast – meaning maintain bentgrass in this part of the transition zone when the scorching weather kicks on like a furnace.

For golf course superintendents in the mid-Atlantic region – Maryland, Delaware, Virginia, West Virginia and Pennsylvania – keeping bentgrass and other cool-season turf alive during the summer doesn’t begin on June 21, the summer solstice. It begins the previous fall and continues through the winter and spring.

“Everything I did beginning last September to now is designed to get me through this summer,” Salvio says.

Cultural practices

Salvio, who has been at Ocean City for four years, maintains “everything you can imagine” when it comes to greens, including 19 USGA-style greens, 10 push-up greens, and nine greens that are 80 percent bentgrass and 20 percent Poa annua.

“I’m a mixture of old school and new school,” he says of his management approach.

One of Salvio’s biggest agronomic challenges is dealing with the warm nights, which can extend into the fall because of the warm ocean water. It’s not uncommon for the temperature at the golf course to be in the mid-70s at night.

“That’s tough on cool-season grass,” he states.

Whether his techniques are old or new, Salvio keeps them consistent. Since he arrived at Ocean City, he’s focused on balancing much-needed nutrients in the soil, such as magnesium and potassium, so the greens will grow healthier roots heading into the summer.

In the spring, one of Salvio’s first duties is to two-way verticut the greens “as deep as I can get those carbine-tipped blades to operate,” he notes.

Mark Hopkins, the golf course superintendent and owner of Southern Hills Golf Course, an 18-hole public facility in Danville, Va., agrees that achieving healthy greens for the summer begins the previous fall. That’s when Hopkins aerifies and fertilizes the greens to get the turf’s roots growing down into the soil profile as far as possible.

Hopkins believes in frequent aerification. He needle tines the greens every three or four weeks in the summer to allow for proper gas exchange and better water penetration.

Hopkins stresses that he doesn’t have the pressure on him from golfers who want fast greens like some of his peers do at private clubs, so he’s able to slow down green speed in the hot months. Hopkins may begin raising the height of cut in small increments as early as the end of May to preserve the greens for the summer and fall.

Phil Desbrow, the golf course manager at Lakewood Country Club in Rockville, Md., maintains USGA-style greens that are 99 percent Poa annua free. The greens are more pocketed on the front nine and more open on the back, making for two different management scenarios. For instance, overwatering on the front nine could spur disease, but overwatering on the back nine might not be such a bad thing because the greens are in full sunlight and there’s more air movement.

A vital component in Desbrow’s maintenance program is aerification. But it’s not just aerifying that’s key; it’s aerifying enough, he says.

While USGA-style greens are built to accept water and drain it, there could be problems with drainage if too much organic matter – an inch or two – forms in the top of the greens, which means they will hold more water. If a thunderstorm hits on a hot day and the greens hold water, they can literally cook in the heat.

“We combat that by overaerifying to get organic matter down so the greens will drain,” Desbrow explains.

If organic matter is more than 3 to 4 percent, there could be problems, Desbrow says, noting that he keeps organic matter in the greens at 2.75 percent.

“We double aerify them twice a year,” he adds. “We’re constantly getting in there to get [organic matter] out.”

Water management

Hopkins is “stingy” with water, preferring to keep turf on the dry side to reduce disease. He also wears turf-stress detection glasses and is prepared to hand water greens at the first sign of stress.

While hand watering is time consuming for his small staff, Hopkins’ philosophy is to syringe the hot spots on greens twice a day in the afternoon. He instructs crew members never to create puddles on greens when hand watering.

If a thunderstorm dumps an inch of rain on a hot summer day, Hopkins and his crew will push the water off greens with squeegees so the water can’t scald the turf’s roots.

Salvio has embraced the PDR (polarization-dependent response) meter to measure moisture on the greens. By measuring in the morning, he can usually tell if the greens will need to be irrigated or hand watered in the afternoon.

Salvio began using a soil-penetrant wetting agent about five years ago, which moves water off the surface, through the thatch layer and into the root zone, keeping playing surfaces firmer and drier.

“It has made my life a lot easier and has changed the way I manage water,” he says.

Salvio also hand waters greens less than he used to because of the benefits of wetting agents, which he sprays about once a month during the season.

“We’ll pump spray the trouble spots, and they’re no longer trouble spots for about six weeks,” he says.

Desbrow’s motto is “dry and alive,” which he preaches to his crew.

“You can always add water, but you can never take it away,” he says.

Desbrow and his staff are also big fans of moisture meters.

“We use them constantly,” he says, noting that he aims to keep the greens at 11 percent moisture.

Fertility philosophy

Desbrow is careful not to overfertilize, noting that a lush green is a slow green. Over-fertilization will also increase organic matter buildup in the greens.

“My strategy from a fertility standpoint is to try and grow back grass from an aerification, which is twice a year,” Desbrow explains. “We average about 3 pounds on our greens. But we generally gear that around aerification to heal it up as quickly as possible.”

In the summer, Desbrow turns to foliar feeding – about 1/10 of a pound of nitrogen or micronutrients to keep the turf “rocking and rolling,” he says.

In March, April and May, Hopkins fertilizes with granulars, and then he changes to foliar feeding every two weeks with an organic concoction. He added a new bio-nutritional product to the program this season. Hopkins also sprays a mixture of iron and molasses, which helps prevent thatch.

Salvio subscribes to foliar and soil feeding in the spring and summer. It’s a lot of hard work for 36 holes, but the results make it worth it, he says. One soil-feeding product he uses is a liquid humic acid that decreases nutrient tie-up and promotes availability of nutrients in the soil.

“We do a lot of spraying, but it’s at a light rate so we’re consistently feeding and consistently stimulating the plant,” he says.

Fungicide programs

Salvio’s philosophy is to spray lightly and preventively, with many of the sprays coming in the spring.

“We apply a few DMIs (demethylation inhibitors) in the spring to help suppress the dollar spot and fairy ring,” he says, adding that he also uses fungicides that attack soilborne pathogens to keep root systems healthy.

A virulent form of dollar spot has posed challenges at Ocean City, which eats down to the crown of the turfgrass and keeps it from recovering. Salvio tries to keep the dollar spot at bay by adding a little chlorothalonil in the spray tank with his weekly sprays, allowing for a constant contact fungicide on the greens. He also changed the nozzles on the spray tank to large air-induction nozzles to achieve better coverage.

Hopkins uses a mix of brand name and generic fungicides for disease control. In the early summer, when the Penncross greens are more susceptible to dollar spot, he sprays a fungicide featuring the active ingredient boscalid, which provides up to 28 days of control. He also uses an azoxystrobin fungicide to control Pythium, and lists chlorothalonil and iprodione as mainstays in his fungicide program.

Hopkins will spray every week if he must to stay on top of disease. If conditions aren’t ripe for turf disease, he might go two weeks or more without spraying.

Desbrow describes himself as a minimalist when it comes to his fungicide program. He’ll go three weeks without spraying if he can. “It depends on the time of the year,” he adds.

Pythium is not a major problem because fertility is low, Desbrow explains. He keeps an eye on brown patch, especially if a thunderstorm crops up during hot weather. Dollar spot is also not a major issue because the greens are rolled four times a week, and rolling reduces dollar spot. Desbrow and his crew are also rolling approaches this season to combat dollar spot. He’d like to purchase a few fairway rollers because dollar spot is a big problem on the course’s fairways.

Since arriving at Lakewood, Desbrow has reduced the fungicide budget by nearly $30,000. He spends a lot of time scouting for disease and doesn’t like to make blanket sprays.

The most Desbrow will spray is every eight to 10 days. When he does spray, Desbrow admits he sleeps well at night, though.

Desbrow, as well as Salvio and Hopkins, are impressed with new fungicide technology, particularly products that feature active ingredients that last up to 28 days.

A few Lakewood greens have fans, and Desbrow says he would have them on every green if he could to promote airflow and cool greens by even a few degrees.

Lastly …

Tending cool-season grass in the mid-Atlantic is like catching for a knuckleball pitcher, says Hopkins, who isn’t sure what kind of weather to expect this summer after coming off a cold winter. But his approach remains the same.

“Be prepared and expect the worst,” he advises.

While Desbrow is sold on some of his cultural practices, especially his aggressive aerification program, he knows that every golf course is different, even if they get the same stifling hot and humid weather.

“What might work for someone else might not work for you,” he adds.

Salvio admits that doing all the things he has to do to get the greens healthy leading up to the summer can be a pain in the neck. But it’s a pain worth enduring.

“It’s a lot of work,” he says. “But the payoff is having a lot better summer.”