Published: April 26, 2017 By
CU Boulder is avoiding chemical weedkillers with a new machine that kills weeds with a shot of steam.

Housing and Dining Services Turf Manager Darren Willett had already been researching steam as an option for weed control on the CU Boulder campus when the 2013 floods hit, ravaging much of the Front Range yet providing a real-life example of just how effective the practice might be. Four years later, that “aha moment” is helping drive transformational change of the weed-management practices in the University of Colorado Boulder’s landscape beds and natural areas.

Grounds technician Pedro Vasquez uses a machine that provides hot steam to safely kill weeds

CU Boulder grounds technician Pedro Vazquez uses a machine that provides hot steam to safely kill weeds.

Housing and Dining Services (HDS) is beginning its second spring of utilizing machinery from Australian company Weedtechnics that uses saturated steam to kill weeds in landscape beds. The initial pilot with one machine last summer has led HDS to purchase a second this year.

Last summer’s results also proved successful enough that Facilities Management (FM), which oversees grounds operations for all general-fund buildings on campus, has just purchased its own machine. FM officials believe the machine could lead to at least a 60- to 70-percent reduction in herbicide use in landscaped areas.

Improving standards

Back in the summer of 2013, Willett was investigating how to improve appearance in HDS’ landscape beds. Just a couple of years earlier, CU officials had made the decision to go herbicide-free in the treatment of all turfgrass areas on campus. But HDS had taken the additional step of going herbicide-free in its landscape beds to align with the desires of residents living in on-campus housing.

The only problem? The amount of real estate where HDS was hand-pulling weeds proved unmanageable for the size of its crew.

Enter the September 2013 floods. In the aftermath, Willett and his team noticed an area near the Bear Creek Apartments at Williams Village where a flooded steam vault had released steam and superheated water through vents in the ground.

The steam and hot water wiped out all grass and other vegetation in its path. But where the steam and hot water didn’t go, everything was fine. The case illustrated to Willett that steam would be both topical and effective in killing weeds.

“We’d heard about steam, and as we started looking at it, it just made sense that it would be viable and user-friendly on campus,” Willett said recently. “What the flood gave us was an inadvertent example of that right in front of our eyes, which kind of gave me a little bit of excitement that this would really work. And we just went from there.”

Emboldened by that experience, Willett and other HDS officials began investigating steam-based weed-removal options in 2014, including the idea of having a machine built locally since the practice is not widespread in the United States. Eventually, the team chose the Weedtechnics machine, making CU Boulder the first college campus in North America to employ the company’s technology when it purchased its first machine last spring.

The patented Weedtechnics machine utilizes a boiler, pump and a proprietary head that is roughly 4 inches by 12 inches. The machine superheats water under pressure to raise the boiling point. As the water enters the chambers of the nozzle system, it explodes into saturated steam, essentially a mix of steam and boiling water that blows up the cells of weeds.

Rather than delivering the steam at high pressure, the Weedtechnics nozzles release the saturated steam at a low pressure so that the process doesn’t damage landscape beds. The hood over the nozzle, meanwhile, ensures that only weeds are killed while desired plants are shielded from the steam application.

During HDS’ initial tests last summer, the machine was able to cover 63 percent more ground per hour than pulling weeds by hand, with groundskeeper Pedro Vazquez running the system and conducting data collection. HDS piloted the machine mainly around some of the residence halls that surround Farrand Field. The second machine will be used this year to focus on areas around family housing, as well as in parking lots.

“We could not control weeds to the standard we wanted by hand,” said HDS Facilities Manager David Lawson, who joined CU in 2014 and helped Willett make the case for purchasing the first Weedtechnics machine. “The machine allowed us to have a high presentation standard in the landscape without using chemicals or hiring a lot of additional staff.”

Benefits of steam abound

While Lawson said that improved presentation standard was the main goal for HDS, the benefits of the machine are many. The chemical-free factor, of course, is a major one that promotes improved soil health, employee safety and other decreased environmental impacts.

Close-up of weed that has been killed using hot steam

There is no need to return to remove the weeds after the steam treatment; they decompose on their own and are gone within a few days.

But because the machine explodes the cells of weeds, there is also no need to return to remove the weeds. They decompose on their own and are gone within a few days. The steam process can also be used in all weather conditions, whereas with chemicals, wind or rain means lost workdays.

Another benefit of steam is that the heat helps to germinate weed seeds. While that initially leads to more weeds sprouting, it also helps exhaust the weeds’ seed banks and eventually leads to much lower-maintenance beds.

HDS also hopes to use the machine as a steam cleaner for things like gum removal on sidewalks and cleaning up stains on the side of buildings left behind by sprinkler systems.

“It’s something where I think we can keep the machine running all year,” Lawson said.

He noted the machine provides a good opportunity for student employees, as well, because it’s relatively simple and safe to operate.

Facilities buys in

For Facilities Management, the big benefits of the machine were the chemical-free and all-weather capabilities. While FM is herbicide-free in its treatment of turf, chemical spray is still used in many of FM’s landscape beds and native areas. Rain washes spray off of weeds, wind causes overspray, and temperatures above 85 degrees render chemicals ineffective, all of which lead to lost productivity.

“I don’t see why we won’t see at least a 60 to 70 percent reduction in chemical use in beds and native areas thanks to the machine,” said Don Inglis, assistant director of outdoor services for Facilities Management. Inglis added there might be some limited areas that aren’t accessible by the machine, but the ultimate goal is to eventually operate completely chemical-free in the beds and native areas.

Inglis said he and his crews closely watched housing’s results last summer, and he’s convinced increased efficiency provided by the machine will give his workers extra time to focus more on other proactive practices like planting, fertilizing and soil treatments.

In addition, both housing and facilities this summer will be testing out the use of a new “dandelion spike” with their machines, which Weedtechnics designed to kill dandelions in turf areas while causing minimal harm to surrounding grass.

“I’ve got to give housing props for researching this, coming up with the funding and then doing the experimentation,” Inglis said. “We were thankful because it gave us that opportunity to essentially try before you buy. There’s a lot of purported silver bullets out there with varying degrees of accuracy.”

CU leading the way

While steam weed control has gained popularity in places like Europe and Australia, the practice is just starting to, well, pick up steam in the United States, with just a handful of technologies available on the market.

Weedtechnics, a company focused on sustainable weed-management plans, has sold more than 100 of its machines, mostly to organic farmers in Australia. But owner Jeremy Winer said landscape contracting giant BrightView recently commissioned one of the machines to pilot at Facebook’s campus in California. He expects to start adding municipalities this summer, including Orange County, California.

“CU provides an opportunity for us to try new things, and it’s great to work at a place that is supportive of innovative ideas,” Lawson said. “I think our use of the Weedtechnics machine opens the door to other campuses and gains CU respect as an innovator.”