LPG Gas for Flame Weeding
Increased legislation and consumer pressure are forcing growers
to look for alternative methods to chemicals, many of which are now banned or
severely restricted.
Flame weeding, burning of weeds (also flame cultivation) is the killing of
weeds with intense heat produced by a fuel-burning device, LPG burners or
torches either hand-held or tractor-mounted. As LPG is nontoxic and does not
contaminate ground water, it is an acceptable non-chemical weed control option
in organic production. LPG, propane, butane powered weed flamers or torches
negate, in an eco-friendly manner, the need to treat crops with acid. Flamers
which use a concentrated flame to damage or kill weeds, have generally become a
popular alternative to using chemicals for weed control, desiccation and as a
soil hygiene tool. They enable growers to keep on top of weed pressure,
reduce yield losses and save considerable hand weeding costs.
Recent advancements in LPG weed flamer technology have made also the process
easier and quicker than ever before. This adds an effective and economical weed
control method to the organic farmer's toolbox.
An LPG weed flamer or torch, uses LPG-fueled flames to transfer heat to weeds
over a short exposure time. It uses different amounts of LPG and pressure to
vary the heat created by its concentrated flame. The user sprays the flame near
the weed leaves or stalks. The flame does not char the leaves, but instead
quickly heats the water inside the plant cells. Because plant cells are filled
mostly with water, the pressure from this quickly heating water causes the
cells to burst.
Without a way to move water
and nutrients from roots to leaves (disruption of photosynthesis), the weed
dries out and wilts. This is usually accomplished in under 2 seconds, without
injury to planted crops. Future weed re-growth will also be stunted, but
permanent elimination of the weed depends on the degree of damage inflicted in
the initial spray, as well as the depth of the weed's root system. Some studies
have shown weed flamers to be most successful with a repeat application. A
repeated application when the new growth is approx 1-2 inches long and the root
structure is still weakened will further weaken and eliminate the
plant. Post emergence burning works very well in crops with energy stored
in tubers or bulbs such as potatoes and onions. LPG flaming can control several
different weeds on a variety of crops, and it offers a time-saving,
soil-friendly alternative that reduces moisture loss and can be repeated as
needed during the growing season. It is highly effective on young, annual
weeds. Perennial weeds with taproots or woody stems may require re-flaming or
additional cultivation. Broadleaf weeds are more readily killed by flaming than
are grasses. In highly intensive cropping systems, high levels of heat applied
via LPG burners not only destroy post-harvest debris but also kill weeds and
any fungal spores on or near the surface. This can help create a sterile seed
bed and minimise the disease pressure on the following crop.
LPG weed flamers are
available in a range in sizes designed to suit different needs. Small hand-held
or 'walk-behind' versions (handheld wands), powered by smaller LPG cylinders,
are ideal for tackling troublesome, hard-to-access areas. These are also used
by domestic consumers for driveways, yards, gardens, around rockeries and along
fence lines. The intense heat destroys any surface un-germinated seeds.
This is a great way for them to drastically reduce new weed growth in before
planting out seedlings. Market-farming equipment options also include
push-wheeled multiple-torch flamers mounted under a flame hood. These
small-scale units are easy to operate and very convenient for flaming on farms
with many small, sequential plantings of crops. For farmers and growers with
large businesses and high acreage, tractor-drawn weed flamers enable maximum
ground to be covered in minimum time. This highly efficient method features a
mobile LPG tank strapped to the tractor, allowing a large area to be treated in
one go without the need for refills. These kits are available in multiple-row
models, with or without a flame hood; other options include a complete toolbar
setup with accompanying cultivator attachments for between-row mechanical
cultivation.
Recent technological advancements have also seen the development of hooded weed
flamers. These consist of regular LPG flamers but with torch hoods that better
focus the flames, protecting them from the elements and enabling them to kill
weeds more effectively and reduce fuel consumption. A split-hood configuration
allows more mature crops to flow through the machine undamaged while an
adjustable torch mount enables a wider range of treatment capabilities.
Organic growers are excited about flaming because in many cases it works as well as herbicides, is amazingly cost and labor effective, can be done when fields are too wet to cultivate and does not bring dormant weed seeds to the surface. Flamers are easy-to-use, safe, and timesaving gardening tools.