Alfalfa Field Flamer

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Alfalfa Flaming Kills Weeds, Grasses, and Weevil the safe, natural way while increasing yields of weed-free hay and saving you money over other methods of weed and weevil control. The heat will kill insect eggs - chemicals will not.  
Also effectively treats field dodder.

Red Dragon® Alfalfa Flamers offer producers a single solution for what is usually a two-part problem. One flame application replaces insecticide treatment for weevil and replaces herbicide treatment for unwanted weeds and grasses.

Due to the fact that weevil lay eggs all winter, flaming is normally done in late winter or early spring, just before or during green-up. Flaming usually takes between 20 and 30 gallons (76-114 Liters) of propane per acre, depending on the outside temperature when flaming. A second application, if necessary, should be done immediately following the first cutting. This will not hurt the alfalfa but may delay the second cutting by a few days.

Flame Engineering's Patented liquid propane spray process was developed in the 1960s and still works today. By directing the spray at ground level, all plants and insects are subjected to high temperatures thus burning out old growth, making way for new, and eliminating weevils. It takes just a split second to kill weeds, grasses, and insects. Tall stubble will, however, require slower ground speeds and higher pressures.

Red Dragon® Alfalfa Flamers are Safe and Easy to Use. Flamers are designed to skid behind the tank cart (tank and cart are not included) and comes with electronic controls allowing the operator control of the liquid spray from the driver's seat. Each unit flames a 12' swath – to connect two or more, call for advisement on pressures, ground speeds, and capabilities.


  • Complete control head assembly with either electronic solenoid valve or manual pull valve.

  • Cab control box with a master shut-off switch (solenoid units).

  • (2) LT 3-12 T Liquid Pilot Torches

  • All necessary hoses cut to length with brass fittings.

  • Valve Protector

  • Red Dragon® Vapor Torch Kit for lighting 


What is the average fuel consumption and cost per acre?

You can expect to use between 20 and 30 gallons (76-114 Liters) an acre. The cost per acre depends on the price of propane.

When is the best time to flame alfalfa?

The best time to flame is in the late winter or early spring when you see the first signs of growth in your alfalfa.

Will flaming hurt my alfalfa?

No. If the alfalfa is green, it will only slow growth for a few days, but there will be no adverse effects.

Can I flame between cuttings?

You may flame between cuttings if necessary. Typically, this will delay the next cutting by 3-5 days.

What size tank is recommended?

No specific tank size is needed. The tank size is determined by how long you want to operate between refills. Using 500 to 1000 gallon tanks is common.

Can more than one unit be hooked together to cover a wider swath?

Yes. 2 or 3 TD12LPS units can be connected to make a 24' or 36' set-up. The producer is responsible for the additional plumbing and fabricating to make this possible.

How fast can I travel while flaming?

Ground speed around 3-5 miles per hour is recommended. Speed will vary depending on the amount of foliage.

In 1938 an Alabama farmer had an idea. Price McLemore discovered that the flame from a kerosene burner would destroy the weeds in his cotton and corn. A machine was assembled and several acres of his corn and cotton were flamed cultivated. This first known attempt at flame cultivation from a tractor-mounted unit consisted of two kerosene burners per row on a two-row unit. The fuel tank was pressurized with a bicycle pump, which would supply the necessary fuel to the four burners. This must have been quite a sight to neighboring farmers as he drove the tractor with one hand and pumped like crazy with the other hand. It was crude but effective.

For several years he attempted to arouse interest in his process by presenting it to agricultural research institutions and experiment stations. Most of his efforts were met with disbelief and laughter. Finally, in 1942 Louisiana State University began experimenting with flame weeding in sugar cane under the direction of Dr. H. T. Barr. The Delta Branch Experiment Station included flame cultivation in their 1943 cotton weed control project, and in 1944 they began work with corn and soybeans. The results of these experiments were very promising, especially in cotton, and generated a great deal of interest among farmers in Louisiana, Mississippi, and Arkansas. It is estimated that by 1946 there were at least 1,000 flame cultivators in the cotton fields of the Mississippi Delta.

Soon after, the International Harvester Company began researching flame cultivation and developed a cast iron burner. It produced a relatively flat, fan-shaped flame which improved the coverage area as the unit moved through the field. However, this project was abandoned due to a corporate decision.

One of the next developments in row crop cultivation was the addition of another burner, sometimes under a hood, to control the weeds and grass between the rows. This was not universally accepted, according to J. W. Gotcher Sr., President of Gotcher Engineering and Manufacturing Co., an early manufacturer of flaming equipment. "Most growers thought it was necessary to stir the soil at regular intervals throughout most of the growing season for maximum plant growth and production" according to Gotcher. The third burner technique became popular when frequent rains caused the fields to be too wet to cultivate in a conventional manner.

It is estimated that by 1960 there were 15,000 flaming units in the fields, most of which were being used in cotton with some used in corn and soybeans. At about this same time interest was growing in non-selective flaming of mint and alfalfa.
In the years that followed, research proved that flame cultivation can be used on 30 to 40 different crops with good results. Although the majority of the research has been done with corn, cotton, and soybeans, many other crops such as milo, garlic, blueberries, strawberries, radish, lettuce, potatoes, asparagus, grapes, fruit trees, and the Australian tea tree all have been successfully flame cultivated.

The objective of row crop flaming is not to "burn the weeds to a crisp" but to expose the weed to enough heat to vaporize the water in the plant cells. This will destroy the plant's ability to move moisture and carry on photosynthesis and in a short time will cause the plant to wither and die. The time that the flame must be in contact with the weed will vary with the type and size, but in most cases, 1/10 of a second is enough exposure. Small, tender plants are more susceptible to heat than more mature growth, therefore the crop needs to be larger than the weeds or grass to be controlled. Some plants by nature are more resistant than others to the 2000° F. blast of heat from the torch. The best way to tell if you have sufficiently exposed the weed is to perform "The Fingerprint Test". To perform this test, squeeze the leaf between your thumb and finger. If you leave your "fingerprint" the weed has been exposed to enough heat to kill it. When preparing to flame, the speed, torch angle, fuel pressure, and other variables need to be considered.

A proper burner setting is necessary for weed control and to prevent damage to the crop. In some cases the crop will be stressed, however, it will recover in a very short period of time. Normally the burners are set at an angle of 30-60° from horizontal (See figure 1), 4-10 inches from the crop, and a pressure of 25-70 PSIG. Tractor speed will vary from 2.5 to 5 mph. Generally, torches are staggered when moving through the row so as not to collide with the flame from the opposite burner (See figure 1). By directing flame into the crop row from both sides, more complete coverage and faster ground speeds are possible.

A different application would be pre-emerge flaming, sometimes called seedbed sterilization. This is generally performed before the crop is planted to remove any weeds in the seedbed and to give the crop a viable start. A variation to this technique is to flame 3-4 days after planting, just before crop emergence, to give the crop a good weed-free start.

Flame Engineering Inc. manufactures complete units and kits, which mount to the producer's toolbar. Our complete unit comes with skid style legs, tank cradle, and protection cage. When ordering a kit, the producer has the option of either skid style legs, like the complete unit, or drop-down legs suspended from the toolbar. The kits do not include tank cradle or rollover protection.
Figure One

Background Information
Broadcast flaming is a technique that is used for weed and pest control in alfalfa. Alfalfa flaming was a common practice throughout the High Plains in the 1960s before herbicides and pesticides were available. Liquid propane spray, directed towards the ground, creates combustion at the point of contact. Flaming takes place anytime after the first killing freeze in the fall up until the alfalfa plants start new growth in the spring. Flaming early in the growing season removes stubble and reduces the breeding habitat for alfalfa weevils. Also, a producer can flame after his first cutting if alfalfa weevil pressure warrants another treatment. Normally, flaming ends after the first cutting.

Practices and Techniques
To properly flame alfalfa there are some general guidelines to follow. The liquid spray bar needs to be raised to a point that it will clear the foliage. Next, the spray bar needs to be adjusted so that the liquid propane is directed to hit the ground about 18 inches behind the spray bar. The pressure should be adjusted to maintain liquid spray across the entire spray bar. Pressure gauge readings will vary with temperatures, but a good rule of thumb is to set pressure at approximately 40 PSI when the temperature is 30°F., approximately 80 PSI when the temperature is 90°F. Ground speed and fuel consumption will depend on the air temperature and humidity. On hotter days the plants need less exposure to the flame than on colder days. For example, on a 100°F. day, it is only necessary to increase the temperature of the plants and pests to 120°F to create steam from internal moisture. On a 30°F. day, it is necessary to increase the temperature to 190°F to obtain the same results. So when the air temperature is around 30°F., speeds will be around 3 to 5 mph and when the air temperature is around 90°F., ground speed will be around 6 to 8 mph. Foliage and residue in the field also affect travel speed. Flaming alfalfa on windy days is not recommended. Headwinds or tailwinds may cause flames to sweep over hoses and controls creating a hazardous situation.

At Flame Engineering Inc. we produce the Red Dragon® TD-12 LPS Alfalfa Flamer. It utilizes our patented liquid spray process developed by Flame Engineering Inc. The 12' unit is usually pulled behind a propane tank trailer.


Byrd and Snipes, C. E. Flame Cultivation in Cotton. 1996. (August 8th, 1999).

Chappell, W. E. "Flaming of Corn, Soybeans, and Vegetable Crops" Fifth Annual Symposium on Thermal Agriculture (1968) 55-56.

Moyer, Dale D. Development of a Propane Flamer for Colorado Potato Beetle Control. Cornell Cooperative Extension. 1991.

Parks, Jack H. "Progress of Flame Cultivation in the Texas High Plains and Rio Grande Valley." Proceedings of First Annual Flame Symposium. (1964) 8-17.

Smith, Bryant, and Hall, M. Flame Cultivation to Control Weeds. University of Kentucky Cooperative Extension Service. Bulletin 269. Undated.

Wilson and Ilnicki, R. D. "Control of Annual Weeds in Cole Crops." Proceedings of Third Annual Symposium. (1966) 18-21.


Always consult your propane dealer about purchasing the proper tank or have them check your existing tank to make sure it is clean and safe before you begin flaming. You MUST use a propane tank equipped with a Liquid Withdrawal Valve. Do NOT use a bottom withdrawal valve as any possible debris or scale may plug torches or solenoids down the line. We recommend a top-mounted, liquid withdrawal valve with a dip tube that reaches close to but does not rest on the bottom of the tank. Clean fuel and tanks are critical for the optimum performance of all flaming equipment. Please check with us before selecting a propane tank.




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