Whether you have heard about superintendent Mark Hoban’s approach at Rivermont Golf Course through the grapevine or watched videos about it online, you know before you arrive that something uncommon is brewing there.
His peers call him “The Mad Scientist” for his unconventional methods, which include brewing compost extract and tea, topdressing with carbon, and on-course trials of all sorts of chemical and organic concoctions. His goal is simple: to infuse his golf course soil with trillions of microbes that feed microorganisms and support healthy turf.
“I’m feeding the soil, and that’s a totally different way to look at turfgrass management,” he says. “We are using live organisms to mine the soil of micronutrients and feed the grass.”
Hoban wants to pair raw data with the results of his organic efforts. In 2012, when Rivermont first introduced compost, Hoban reduced nitrogen use from an average of 2.5 pounds per thousand on the fairways to 0.62 pounds, and fungicide applications were reduced from 15 per year to three. These averages have continued for the last five years and today, Hoban estimates that 50 percent of his fertilizer inputs are organic. He has applied fungicide only twice this year.
Known as the “Mad Scientist” among his superintendent friends, Mark Hoban pursues his passion for reducing fertilizer and pesticide inputs with his own trials at Rivermont Golf Course in Johns Creek, Ga. “I think this is the right path to go down, but it’s certainly not cut and dry. I think these are things that warrant further observation.”
“I just know I have lowered fertilizer and pesticide costs, although I don’t know how much,” he says. “I get to spend that money on tees and fairways and greens.”
The use of thermal compost has decreased disease pressure at Rivermont, a private 18-hole course in Johns Creek, Georgia, which is a combination of naturalist’s delight and outdoor science lab.
“What I have come to believe is that providing healthier soil is, in its own way, a system to control and prevent disease to a certain extent,” Hoban says. “Thermal compost has reduced the amount of dollar spot we see on fairways, and if I were to use a fungicide, it would cost $4,000 to $8,000 per application. We’ve also had hardly any spring dead spot in areas treated with thermal compost in comparison with the untreated checks.”
Make Your Own Compost Tea Recipe
Tea must be applied solo or else viable microbes will die. Hoban puts his tea out monthly.
To brew his tea in a 250-gallon compost brewer, follow these simple directions:
- Begin by placing 3.25 gallons of compost from a diverse blend of sources inside a bag in the brewer.
- Use only non-chlorinated water (water can be aerated to remove chlorine if needed).
- Add food to the mix, including molasses and fish hydrolysate. Feeding can produce trillions of microorganisms very quickly.
- Simmer the tea for 48 hours to produce the richest broth of microbes.
- The tea only has a shelf life of three to four hours once it is removed from the oxygen source and funneled into a spray tank. Hoban applies about 20 gallons per acre.
Hoban says the extract and tea applications cost less than $20 a month, and although some might suspect that these methods are labor intensive, Hoban says he hasn’t seen any increase in labor costs.
Brewing for a beautiful green
As a family-owned course – with owners who are keen on natural practices and members who have fallen in love with the course’s old-world style – Rivermont is an ideal location for Hoban’s efforts.
A past recipient of the Georgia Golf Environmental Foundation’s Environmental Leader in Golf award, Hoban’s curiosity keeps him in cahoots with university researchers. He and a University of Georgia researcher hope to receive funding from Georgia superintendents for a two-pronged research project to investigate the effectiveness of beneficial fungi, as well as the impact of non-organic products on soil microbiology in turfgrass.
Mark Hoban checks the temperature of his thermal compost pile at Rivermont Golf Club. Hoban uses this 250-gallon compost tea brewer to create the extract and tea that fuel microbial life in his soil.
While he seeks new approaches for lowering inputs, Hoban enjoys teaching others about his tried-and-true composting approach.
Outside his shed at Rivermont, two large piles of material produce steam: a thermal compost and a vermicompost from worm castings. The thermal compost is a heaping pile of grass clippings, wood chippings and other materials that is three parts brown (for carbon) and one part green (for nitrogen). The temperature is indicated by a thermometer stuck into the side of the pile, which really begins “cooking” at about 135 degrees. Hoban says the material will be flipped or stirred before it reaches 160 degrees, because any temperatures higher than that will cause the compost to become anaerobic.
To create the second pile, Hoban and his crew used a five-shelf worm farm to supply much of the vermicompost material that went into the compost brewer. The success of the program has prompted the course to purchase between 60 and 100 tons of the compost, which is used in the tea and broadcast onto fairways and tees. The worm farm still contributes compost matter, however, and is part of Rivermont’s education outreach.
For those who want to start their own composting project, Hoban suggests that beginners start by making compost extract because it can be folded into fertilizers and other inputs without detrimental effects. The extract produces 250 gallons in 20 minutes and has a four-month shelf life. Hoban includes it with all spray applications.
Compost tea is trickier for beginners because it requires nutrients and produces more microbes than ever occur in nature, which makes its application urgent. Aeration removes beneficial organisms including bacteria, fungi and protozoa – all important in the soil’s microbiome. Tea must be applied solo or else viable microbes will die. Hoban puts his tea out monthly.
The tea has a shelf life of three to four hours once it is removed from the oxygen source and funneled into a spray tank. Hoban applies about 20 gallons per acre.
Hoban says the extract and tea applications cost less than $20 a month, and although some might suspect that these methods are labor intensive, Hoban says he hasn’t seen any increase in labor costs.
“It is part of my turf management program. I spray more, but that is offset by the lack of money spent going the inorganic and synthetic route,” he says.
The turf treated with biochar (right) about three weeks after it was applied at Rivermont Golf Club.
Composting has other champions, too
Superintendents across the country have tried compost tea on and off for many years. Josh Heptig, superintendent and director of golf course operations with San Luis Obispo County Parks & Recreation in California, oversees three golf courses and has established a “Zero Waste Park” initiative at Dairy Creek Golf Course to minimize waste and maximize recycling.
During Heptig’s first three years at Dairy Creek, more than 60,000 pounds of food waste were diverted from a landfill and, with a little help from earthworms, processed into compost, which he then brewed into tea for the course.
Heptig was working with a nearby university program to monitor trial applications on six putting greens, but the professor in charge of the program left and has not been replaced. Meanwhile, the restaurant operator who was the source of material for the compost went out of business, so the compost tea applications at Dairy Creek ceased. While the goal of the program was reducing waste rather than improving soil health, Heptig said it would be helpful to have more concrete data about the efficacy of compost tea.
“It’s really tough because there’s not a lot of scientific research done on compost and turf,” says Heptig, the 2017 recipient of GCSAA’s President’s Award for Environmental Stewardship. “It’s been cost prohibitive, but organics are becoming more competitive pricewise. I think there’s interest in it, but sometimes we are set in our traditions and if something works, it’s hard to move away from that – especially when the job market is very volatile.”
At the University of Colorado (CU) in Boulder, Ryan Heiland found a way to irrigate 100 acres of campus with compost tea using the irrigation system already in place. Nine 250-gallon brewers create the tea from vermicompost, which is distributed during the normal watering cycle: every four or five weeks during growing season.
“We still use a synthetic fertilizer once a year on our general campus landscape turf, but we use compost tea and everything above the ground is easy to grow if you have good ground underneath,” says Heiland, who is assistant manager of outdoor services at CU and has a background in the golf industry.
“With compost tea, I envisioned working through the process,” he says. “There’s less science behind it. It’s not the same as putting a certain amount of nitrogen down and knowing you will get this result.”
After six years of applying the compost tea, Heiland says the university has not used pre- or post-emergent herbicides.
“I don’t have the risk a golf course superintendent in the private industry has,” Heiland says. “I am protected in a system like the state system and if something goes wrong or dies, I don’t lose my job so I am able to fiddle more. If you want to go natural, you have to cede some of that control to Mother Nature, and the university’s administration understands that.”
Punctuated by native grasses and brown bunkers, Rivermont Golf Club of Johns Creek, Georgia, is situated on the north side of the Metro Atlanta area. The club’s natural approach reaches into its soil microbiology, which is fed regularly with compost extract and tea.
Other organic approaches
Hoban’s more natural approach is pervasive at Rivermont, where 27 acres have been surrendered to natural grasses such as broomsedge, orchard grass, rattail fescue and switchgrass. Pollinator and bluebird boxes dot the edges of the course, and a monarch garden is under construction.
It should be no surprise, then, that Hoban has found a way to infuse his topdress with soil food. He mixes about 1,000 pounds of carbon with his sand to create “invisible sand” because its presence can’t be detected for long.
“That will get me about six acres of topdressing on greens and I will probably use seven loads a year, maybe more,” Hoban says. “It is humic and fulvic acid released in the soil, and microbes are able to break it down.”Microbes will gnaw on the carbon,” which acts as a catalyst for microbial activity. “Plants use carbon exudates with sugars in them to attract the microbes around the root system. That is how the plants are getting their nutrients.”
Hoban is also testing biochar, a charcoal soil amendment, in varying amounts on several tees and fairways to see how it impacts plant health.
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