Fire is a new addition to the farmer's toolbox.
Fire is a new addition to the farmer’s toolbox. Courtesy of Carolyn Olson

Carolyn Olson has a row-crop farm in southwest Minnesota. There, she grows organic corn, soybeans, and alfalfa, among other crops. As with most farmers, organic and otherwise, she constantly fights against weeds. In Minnesota, lamb’s quarter, Canada thistle, and water hemp can threaten crops, she says. But for the last 15 years, Olson has had a weapon in her arsenal: a flame weeder, a contraption that combines farm machinery with firepower worthy of a heavy metal show.

Over the last 15 years, she’s had two flame-weeding rigs. Her current flame weeder is built on the frame of a farm sprayer. But instead of pesticides or fertilizer, it sprays flames out of 36 burners. Meeting the requirements of organic farming often calls for manual weeding, either by hand or with cultivator machines. For crops that can beat the heat, though, flame weeding is an option. This video shows Olson’s prior flame weeder in action.

Olson uses her flame weeder on corn. Since the corn’s growing point, where the leaves and tassels grow, is protected, it can withstand the flames. Other crops have a harder time. “It is risky to flame weed soybeans, but some farmers do,” Olson says. The broadleaf weeds that Olson targets, though, can’t resist the flames. “The heat from the flame causes the moisture in cells of the leaves to expand, and burst the cell walls,” she explains. This kills the weeds. The flames are powered by propane, and an angled heat shield mounted on the sprayer helps focus the heat on the base of the corn.

Flame weeding has been hot before. Fighting weeds with fire was common in the ’40s and ’50s, before chemical weedkillers took over. Now, in response to the rise of organic farming and videos of flame weeding, more people are asking where to buy equipment and how the process works. Olson herself says that interest among organic farmers is growing, as “another tool in our weed control toolbox.” It helps that flame weeders look pretty awesome. “It is the scariest, yet coolest piece of equipment we own,” she says.

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