The clean, green weed control that propane provides benefits organic farmers by reducing costs, increasing yields, and by giving farmers the ability to weed when the ground is wet, several new research studies report.

Flaming weeds using propane only certified-organic option available that benefits organic farmers by lowering costs, increasing yields, reports butane propane news 072019When Randy Fendrich was invited to participate in a research project on flame weeding, he had never before used it at his organic farm. After joining the project and using a four-row flamer to kill weeds in his rows of corn, he was so pleased with the results, he built himself a 12-row flamer. He built it before the project was even complete and he is still using it today.

Flame weeding uses heat for weed control. Equipment mounted to a tractor and fueled by propane sends out plumes of flames directed at weeds in a crop. This does not ignite the weeds, but kills them. The tractor moves through the field at about 4 mph and the weeds are exposed to the high heat for 1/10 of a second. They wilt, fall on the ground, and die. When it’s done properly, the crops are unaffected.

Prior to the research project, Fendrich had been using a rotary hoe and cultivator for weed control in his cornfields at Fendrich Family Organics (Linwood, Neb.). “The biggest benefit is that the flaming gets the weeds so I don’t have to hire workers to cut them,” he says. “I save money.”

Larry Stanislav, another organic farmer, also continued using flaming after learning about it during the research project. At Stanislav Farms (Abie, Neb.), he uses it with corn and soybeans. He started with a four-row flamer and has since added a six-row flamer. Stanislav, too, says flame weeding saves him money and time. What’s more, he adds, it allows more nutrients and moisture to go to the crop rather than weeds.

“Anytime I don’t have to disturb the soil, I’m not breaking down the microorganisms that feed the plants and help them grow,” he explains. “If I can reduce the number of tillage passes, I can improve fertility and save water. It’s beneficial for soil life and it adds to the bottom line. I get a healthy crop and a nice harvest.”

Stanislav adds that using clean-burning propane flamers reduces the need to burn other fuels in other equipment. It also eliminates using sprays or poisons that affect beneficial insects, the ones that pollinate crops, as well as harmful ones. “Propane can be a help in reducing the amount of chemicals guys are using.”

Both Stanislav and Fendrich report that flaming consumes about five gallons of propane per acre. Fendrich does it once a year, right at the beginning of the season when the corn and weeds are small. Stanislav flames the corn once or twice a year and the soybeans once a year, but this year he will try flaming the soybeans a second time as well.

The amount of propane used by other farmers in the research project varied, depending on the method being used, says Dr. George Gogos, one of the researchers who led the study. Banded flaming treats a band up to a foot wide, centered in the crop row. This consumes five gallons per acre, generally twice a year. Full flaming treats a band that’s 30 inches wide. This method consumes 10 gallons per acre, twice a year.

Flamers have many other uses on farms. Some consume as much as 20 to 30 gallons of propane per acre.

The Farm Research Center (Garden City, Mo.;, an independent research farm, has found that using a broadcast burner to burn the entire area of the field consumes 10 to 20 gallons per acre. A broadcast burner is used in the fall, after the combine, to reduce weed pressure in the spring. “If you start clean, you’ll stay clean, especially in organic farming,” says David Yoder, farm manager at The Farm Research Center.
Flaming weeds benefits organic farmers reducing costs reports Butane Propane News 07 2019
Flame Engineering (LaCrosse, Kan.), a U.S. manufacturer of agricultural equipment since 1959, has seen propane consumption rates of six to 10 gallons per acre on the tractor-mounted equipment currently used by farmers. Darren Viegra, who handles sales at Flame Engineering, says farmers use the company’s row crop flamers and pre-emergent flamers two or three times a year, depending on Mother Nature. Farmers use the company’s vineyard and orchard flamers much more often—every 12 to 15 days.

Earth & Sky Solutions (White Hall, Va.;, an agricultural equipment dealer serving the Mid-Atlantic region and other states, tells farmers they can expect to use three to six gallons per acre for vineyard and orchard flaming; four to seven gallons per acre for vegetable bed flaming; five to 10 gallons per acre for row crop flaming; seven gallons per acre for tobacco row crop flaming; and 20 to 30 gallons per acre for alfalfa hay field and potato vine flaming. For poultry house flame sanitation, Earth & Sky Solutions tells customers they can expect to use 25 gallons when flaming a 40-foot by 500-foot house when moving at 1/2 mph.

Gogos, a professor of Mechanical and Materials Engineering at the University of Nebraska-Lincoln, and Dr. Stevan Knezevic, a weed management expert at the same university, led research funded by the Propane Education & Research Council (PERC) and the U.S. Department of Agriculture. The project ran from 2007 to 2012 and concentrated on row crops. Gogos’ combustion lab was used to develop torches and then these were tested in university fields and by five organic farmers. Each farmer would grow crops in five acres using traditional methods and in an adjacent five acres using flaming. At the end of each season, they compared the yield. In the areas that were flamed, “there was consistent yield increase,” Gogos says. “We got yields comparable to hand weeding or conventional farming with chemicals.”

The Farm Research Center has had similar results in its trial of burning for weed and insect control. It grew corn and soybeans and compared the yield of areas that were burned to the yield of areas that were hand weeded. There was no yield difference between the two areas. It also found that when burning is done to crops in the field, it is not damaging as long as the growth portion of the plant is higher than the torches on the burner. This research began five years ago and is ongoing.

The results were phenomenal,” Yoder says. “We found burning was a very efficient way to eliminate weed pressure. We didn’t see a yield drag. If anything, we saw a yield increase, because the crops are not competing with weeds.”
Weed Flaming Cheap Organic Way to Weed crops Butane Propane News. 07 2019jpg
Flame weeding is not new, Gogos explains. It started in the 1850s and was used by as many as 30,000 farmers up to the 1960s. Then, chemical pesticides came into use and flame cultivation almost died out. It was revived in the 1990s, however, when organic farming started becoming popular. Organic farmers can’t use most chemicals, and those they can use are very expensive. They can only eliminate weeds with mechanical cultivation, meaning with a cultivator or by hoeing.

Today, there is room for growth. Only about 0.5% of U.S. farmland is certified organic, but there is double-digit growth every year, Gogos says. In Europe, 5% of the land—10 times the percentage in the U.S.—is organic.

“If you are in organic farming, propane flaming is the tool,” Gogos says. “There is no other organic certified method to get the weeds in the row that compete with the crop. That is the value of flaming.”

There is room for growth among conventional farmers as well. Gogos says he has received calls from conventional farmers seeking a solution for weeds that have developed resistance to chemical weed killers. “It’s a challenge, though, because it is much quicker and easier to spray chemicals indiscriminately than it is to flame,” he adds.

Viegra of Flame Engineering says most of the company’s customers are organic farmers, but its equipment is used by conventional farmers, too. “Weeds are becoming resistant to chemicals, so they come to us to learn about flame technology,” he says. He adds that another benefit to all farmers is that flaming also eliminates insects and larvae and their habitat.

Flame Engineering offers a variety of flamers. For agricultural use, it offers row crop flamers; vineyard and orchard flamers; alfalfa flamers; and pre-emergent flamers. The company also offers a poultry house sanitizer. For smaller farmers, Flame Engineering offers hand-held and walk-behind flamers as well as pull-behinds that are used with an ATV or a tractor. “There’s no specific customer—we have flamers for everything from the backyard to the field.”

Viegra adds the crops flamers are most often used with are corn, orchards, and hemp. “We’ve gotten a lot of phone calls in the last year from farmers growing hemp,” he says. “Growers can’t put chemicals on that; it’s all organic hemp. They can only do hand weeding and mechanical, so flaming is very cost-effective.”

“It’s a good product,” he adds. “With the price of propane, it’s a lot cheaper than hand labor. Plus, weeds will never become resistant to 2000 degrees of heat.”
Earth & Sky Solutions specializes in environmentally friendly solutions for agriculture, including flame technology for chemical-free agriculture. The company supplies Flame Engineering’s Red Dragon flame weeding equipment. Most of its customers are organic farmers, but poultry house flame sanitation tools go to conventional farmers as well. The company also has Red Dragon’s solutions for small-scale growers on its garden tools website (

“We field a lot of questions from farmers who are unfamiliar with flaming,” says Charles House, owner of Earth & Sky Solutions. “Many of those who call are transitioning to organic farming and are looking for non-chemical solutions. I pass on a lot of information.”

Some ask if flaming will hurt the soil or microorganisms. House answers that there is minimal damage to either. Some are concerned about propane, saying it’s a fossil fuel. He answers that propane is nontoxic and can’t hurt the environment. “Propane is a real good fit for organic farmers,” House says.

When a farmer has decided to use flaming, he sets them up with the proper equipment for their crop and situation.

“Any equipment I sell, I go out to the farm for a day to show them the safety features and how to adjust everything,” House says. “My goal is to leave them confident using the equipment. I also provide phone consultation anytime they need it.”

“One thing I say is, ‘Don’t wait for a weed emergency; have the equipment ready before you plant. Be prepared.’”

After seeing the results of their research project, Gogos and Knezevic established a company to build flaming equipment. Today, in addition to his post at the university, Gogos is CEO/lead product developer at the company, Agricultural Flaming Innovations (AFI; Lincoln, Neb.; “We brought flaming into the 21st century,” he says. AFI currently offers one piece of equipment that provides weed control in corn, soybean, sunflower, and sorghum crops. It is available in different sizes, measured by the number of rows it can treat: two, four, six, eight, 12, and 16. These four crops are similar enough that they can be flamed with the same equipment, though the shields that direct the flames must be adjusted.

AFI collects orders from farmers and then produces the equipment at certain times of year. The company currently has one production run in January and a second in March/April. This year, due to growing demand, it will add a third production run in August. It is considering adding a fourth in the fall.

The company also teaches the right method, or “recipe,” to use with the crops. Flaming must be done in such a way that it removes the weeds, but does not harm the crop. “You can develop a great machine, but you must also tell the farmer how to use it with different crops,” Gogos says. “You need to know the sensitivity of the weed and of the crop.”

Gogos and Knezevic have submitted a proposal to PERC for funding to develop a recipe for one more agricultural product: alfalfa. Alfalfa was chosen because flaming does a great job controlling weevils. They are also planning to pursue funding to develop recipes for cotton and industrial hemp.

In addition to his position at The Farm Research Center, Yoder is also research farm manager and product sales at, AgMaxx Inc. (Garden City, Mo.;, a distributor of Flame Engineering’s Red Dragon equipment. In that capacity, he travels to farms to set up the equipment and show the farmer how to operate it.

“Flame cultivation is an awesome tool,” Yoder adds. “We have found ways to simplify organic farming and take a lot of the stress off. With burners, there is more flexibility on timing. For example, we can do it when it’s muddy; we can do flame cultivation when we couldn’t do it with conventional cultivators. We actually saved a crop of soybeans that way. Organic farming is not easy; if it was, everyone would be doing it. But this is a tool we’ve found that simplifies it.”

The equipment and the idea of flame cultivation has spread among organic farmers primarily by word of mouth. “Organic farmers are well organized and they know each other,” Gogos says. He and others from AFI also present workshops at meetings of organic farmers.

At Stanislav Farms, Larry Stanislav found there is a learning curve with flame weeding as there is with any new technique or tool. He says the key to success is doing the treatment at the right time during the crop’s growth. “It’s not foolproof,” he says, “but it is an effective tool in your arsenal and it allows you to reduce the use of other tools.”

(Butane-Propane News magazine, July 2019)