About This Guide
This Agricultural Flaming Guide offers background information on
methods, history, early practices and current methods and equipment.
It is a work in progress and as new information is received the
guide will change to reflect these new concepts or and equipment.
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Row Crop Flaming History
Row Crop Flaming Practices and Techniques
Crop Flaming Recommedations
Grapevine Berm Flaming
Crop Flaming History
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 site 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 andexperiment
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. 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 the
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. 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.
Flaming Practices and Techniques
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 plants 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
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
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 roll over protection.
The flaming of corn, popcorn, field corn, or sweet corn, can be done
at an early vegetative state. Typically corn can be flamed when it
reaches a height of 4 inches and can be flamed until the corn reaches
canopy. Tractor speed should remain in the 3-5 mph range. Other work
has been done on "flaming off" of corn. This approach is
when the weeds are the same height of the corn and the whole field
is flamed off. Corn can withstand one "flaming off" with
only a 4.5% of plants eliminated (Parks 13). "Flaming off"
can be a viable option if a producer is about to lose his corn crop
to weeds. Smith offers these three recommendations for flame cultivation
1. Prepare the seedbed and plant so that the row band (5-6 inches
on each side of the planter) is relatively smooth and flat. Then the
flame can get to the weeds and will not be deflected into the crop.
2. Flame cultivate when the weed growth indicates a need for cultivation.
This should be done while the weeds are small and tender (less than
2 inches tall). Corn can be flamed before it is two inches tall, if
cultivation is needed. To prevent injury to the crop when corn is
flamed at this early stage, do not flame again until the corn reaches
a height of 6-8 inches.
3. Do not move soil into the flame-treated row band when cultivating.
This soil is a source of new weed seeds. (7) Seed corn companies have
also found a specialized use for flaming. In the production of seed
corn, they look for ways to extend the length of time that the male
corn plants produce pollen to pollinate the female corn plants. The
burners are set to direct the flame at the head of the male corn plant.
This causes maturity differences between the plants and different
plants create pollen at different times. This is accomplished through
either a timer switch or a manual switch which allows intermittent
flaming of the corn heads.
Flaming soybeans is slightly more dependent upon critical timing.
It is not recommended to flame soybeans until the plant height reaches
approximately 10-12 inches (Smith 6). With soybeans, staggered cross
flaming is the standard burner pattern with ground speed ranging from
3-5 mph. When flaming soybeans, the burners must be set properly so
as to direct flame at the base of the plant and try and also keeping
heat off the leaves. The following are recommendations for the flaming
1. Prepare the seedbed and plant so that the row band (5-6 inches
on each side of the planter) is relatively smooth and flat. Then the
flame can reach the weeds and not be deflected into the crop.
2. The first flame cultivation should not be applied until the soybeans
are 10-12 inches tall. Succeeding flame treatments should be dictated
by the weed growth.
3. Do not move soil into the flame treated row band when cultivating.
This soil is a source of new weed seeds. (Smith 7)
Flaming of grain sorghum usually begins once it reaches a height of
approximately 8 inches. Staggered cross flaming is the recommended
method of flaming with ground speed ranging from 3-5 mph. According
to Parks, if the weeds and the grain sorghum emerge at the same time
one "flaming off" application can be performed before the
terminal bud comes through the soil surface. Normally, the grain sorghum
plant is 3-4 inches in height when the growing point (terminal bud)
reaches the soil surface (10).
Flame cultivation of cotton can begin once it reaches a height of
4-8 inches. It works best with staggered cross flaming. Tractor speed
is in the 3-5 mph range. Typically, for best control of perennials
in cotton a second application of flame cultivation should occur 2-3
days after the first flaming. According to Byrd, "some of the
advantages to flame cultivation in cotton include: spectrum weed control,
repeat treatment as often as desired, low cost, no residue, no activation
required, can flame when too wet to cultivate, controls large, annual
morning glory species, provides immediate results, and weed response
is independent of environmental stress." (1)
Flame cultivation is performed on potatoes for control of the Colorado
potato beetle (CPB). According to Moyer, these burners were directed
towards the row at 45° from horizontal of the boom and tilted
downward at a 45° angle. The flamer was operated at speeds from
3, 4, 5 and 6 mph (6). Moyer also stated that "the flaming technique
provided 70-80% control of overwintering adult CPB. It was also determined
that flaming reduced egg hatch by 35%, lowering the number of first
generation CPB larvae (6)."
Another use for flaming in potato fields is potato vine desiccation
before harvest. Vine desiccation is accomplished by using Red Dragon
Liquid Spray Torches. Speeds traveled when desiccating vines will
range from 2-4 mph depending on pressure settings and vine density.
It has been proven that tomato plants have the ability to withstand
flaming. Chappell has shown that eight week old transplanted tomato
plants can be safely flamed with excellent weed control and very little
stress to the tomato plants. (56) The burner setting was staggered
cross flaming and tractor speed was 3-4 mph.
The flaming of cole crops, such as broccoli, cabbage, brussel sprouts,
and cauliflower, has been shown to control weeds. Staggered cross
flaming provides the best results with tractor speeds being around
2 mph (Wilson 21). Cabbage and brussel sprouts can be flamed approximately
3 weeks after the plants are transplanted, whereas broccoli and cauliflower
can be flamed around two weeks after transplanting. No decreased yields
are seen with one flame application, and if a second application is
needed it should be done at higher tractor speeds to decrease crop
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 1960's 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 120°F to create steam from internal moisture.
On a 30°F. day, it is necessary to increase the temperature 190°F
to obtain the same results. So when 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 effect travel speed. Flaming alfalfa on windy days
is not recommended. Head winds or tail winds 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
Grapevine Berm Flaming
Grapevine berm flaming is an excellent method of weed management.
The first recorded flaming of grapevine berms occurred in Michigan
in 1963 (NGPA 35), which also included a study of flaming blueberries
and strawberries. The GP 750 and GP 1000 were originally designed
for flaming grapevine berms but have been adapted for use in fruit
and nut orchards. The flaming of grapevine berms helps to remove weeds
and debris, thus reducing insect habitat and breeding grounds, which
in turn lowers insect populations. The alley attachment is an option
which allows one pass control of weeds on the berms and in the alley.
As with all forms of agricultural flaming, grapevine berm flamers
reduce herbicide use and operating costs.
Practices and Techniques
Flaming of grapevine berms can be done on a year-round basis. In the
summer it is used approximately every two weeks and in the winter
a pass will remove plant residues. The burners are set so that weeds
in the row and on the side of the grapevine berms are flamed. In an
orchard setting, the burners are set to control the weeds and grasses
that grow under the tree canopy and between the trees. Ground speed
will vary with weed pressure and gas pressure with an average speed
of 3 miles per hour at 45 psi, producers can expect to use 11 to 21
gallons of fuel an hour. With the alley attachment, fuel consumption
The GP 750 and the GP 1000 are an economical and effective method
of weed control. In addition to saving growers' money and labor, the
flamers reduce environmental damage from pesticide use.
Byrd and Snipes, C. E. Flame Cultivation in Cotton. 1996. <http://www.mssstate.edu/extension>
(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.
Wilson and Ilnicki, R. D. "Control of Annual Weeds in Cole
Crops." Proceedings of Third Annual Symposium. (1966) 18-21.
Row Crop Flamers Complete
Row Crop Flaming Units Row
Crop Flaming Kits Row
Crop Flaming FAQs
Alfalfa Flamers Alfalfa
Vineyard & Orchard Flamers GP-1000
Complete Unit GP-750 Complete Unit
GP Kits & Attachments
Vineyard and Orchard Flaming FAQs
Potato Vine Flamers Potato
House Flame Sanitizer
Vegetable Bed Flamers
SOME GREAT REASONS TO FLAME:
Flaming is a natural weed control that has
been around for years.
Tractor mounted flamers were used effectively as early as 1938 in
cotton and corn.
Flaming can be done when it is too wet to cultivate.
Flaming does not pollute the soil.
Flaming does not pollute the air.
Flaming does not pollute the water.
Flaming is not a carcinogen.
In 1990 460 million pounds of pesticides were used on food crops.
Since 1965, US pesticide use has tripled.
In 2000, sales of organic foods reached $6 billion. This number
is growing by 15% to 20% a year.
Organic grain brings an average of 200% higher prices than conventional
Organic oil seeds bring 300% price premium.
The Environmental Protection Agency is drafting new rules that penalize
farmers that put chemical off into streams and rivers.
Diazinon is being phased out due to health risk.
It takes 20 to 30 years for agriculture chemicals to dissipate from
wells and streams.
If it rains right after a treatment, it does not effect the results.
Flaming is generally less expensive than using chemicals.
Flaming provides additional insect control.
Flaming does not require special licensing.
Weeds and insects develop immunity to chemicals requiring the development
of even stronger and more environmentally threatening chemicals.
There is no carry over or residue.
Flaming does not require any special clothing or protective gear.
Even if you have your chemicals custom applied, you and your family
still breath the chemicals.
Alfalfa flaming is designed to kill weeds and the Alfalfa Weevil.