White Paper
On the Ergonica Weed Twister and Other Alternatives to Precise Hand Weeding in Agricultural Applications

HAND WEEDING VS USING HAND TOOLS

Hand weeding without tools may arguably be cheaper in some situations than hand weeding with tools, or mechanical hand weeding.  However, without the proper equipment, the worker will often tear off the top of the weed and leave the roots in ground.  Not only is this an arduous task and damaging to the health of the worker, but it also may be less efficient when compared with mechanical hand weeding, depending on the types of tools available for this purpose.  In other words, when using the most appropriate ergonomic tools for the situation at hand, the grower can efficiently "Wipe out the weeds, not the workers!"  If children are employed in hand weeding, refer to the North American Guidelines for Children's Agricultural Tasks for care in preventing injury to children.  Some of these guidelines make a lot of sense for adults in some situations, as well.   According to the American Society of Hand Therapists, repetitive movements such as raking, weeding, digging and pruning are stressful on hand and wrist ligaments and can cause tendonitis and Carpal Tunnel Syndrome.

The selection of the most appropriate tools may depend on the types of crops, types of weeds, soil conditions, sizes of weeds, quantities of weeds, weather conditions, costs, and, of course, especially in California, laws and regulations.

In California, the traditional use of the short hoe is not currently a legal option.  Weeding by hand is restricted in agriculture to situations where it can be proven to be necessary.  Organic farmers do not have the same restrictions that other farmers have in the new regulations.  The logic behind this variation is based not on ergonomics, but on the economic requirement for extensive hand weeding for organic farming to be productive. As stated above, whether required or restricted by law or not, tools that are more efficient than hand weeding or the short hoe will be of value to all farmers that require precision weeding or thinning assuming they have an opportunity to evaluate and select the best tools for the job at hand.  Many of the conditions that have traditionally called for hand weeding can be efficiently overcome by the Weed Twister as will be described below.

CIRCLE HOES AND THE WEED TWISTER

To analyze the benefits of the circle hoe, we examine it's features here in a generic sense.  This design is a band of thin metal shaped like a wedding band with a diameter of several inches and a band width of less than an inch.  The example shown below has a diameter of about 3 inches, one inch greater than that of the Weed Twister coils. 

HOE DESIGN VARIATIONS AND THE WEED TWISTER

There are a number of innovative precise hoe blade design variations that are listed on the Weeder Features page and elsewhere for comparison.   One common issue with all of these designs is that they have a relatively sharp edge which will very likely cut the roots of a large weed if applied carelessly.  Like the traditional hoe and the circle hoe, the various blade designs are intended to till and cultivate the soil and remove small weeds with shallow roots.  None are intended to effectively remove the root systems of larger weeds.

PRONG SHAPED WEEDERS AND THE WEED TWISTER

Several traditional weeders have fairly straight prongs, some with curves and grooves, and others with short and long handles.  Prongs are the generic weeders of the past.  Long handled prongs have back-saving advantages over short-handled prongs.  Prongs are more effective than hoes in penetrating deeply into the soil to attack larger root systems.  The longer the handle, the more leverage can be applied to extract larger plants. 

The twisting motion of the Weed Twister will engage the root system and twist the entire root while still in the soil.  The apex of the double coils is carefully designed to grab the root structure that has already been loosened by the coils and force it to dance the Weed Twister Waltz.  Once embraced, the roots will completely disengage from the soil after one or two twists.  The Weed Twister Waltz lifts the weed off her feet!  Once she begins to spin, it is safe to gently lift her out of the soil with very little effort.  A graceful exit from stage left!

In contrast,  once the prong reaches the main root system, it can only move laterally like a lever.  Oftentimes it will simply slip off the main root stem with very little impact.  It may take several thrusts and pushing efforts with the prong to loosen the roots from the soil and ultimately it still requires one or two hands to extract the weed from the soil. 

Both tools have the problem of occasionally missing a central point in the root system that allows for effective removal.  The straight tap root is more difficult to hit by either tool, especially when it angles off in a direction that is not clearly predictable by the visible growth.  The 2-inch diameter of the Weed Twister coils gives the Weed Twister a slight advantage in hitting target the first time over the prong with a 1-inch or smaller diameter.

The more branches and networks in the roots, the more easy it is for the Weed Twister to snatch the roots and twist them into orbit.  This advantage is not enjoyed by the prong.  The Weed Twister is more effective in grabbing and loosening both the tap root and the branched root than the prong.  There is no competition in this regard by prongs, hoes or other shapes. 

The twisting design of the Weed Twister is the most effective and efficient design in attacking grass-type root networks and branched roots, as well as deep taproots, than any other mechanical tools that we have seen to date.

OTHER WEED TWISTERS VS THE ERGONICA WEED TWISTER

There are two other manufacturers that we know of that distribute a product called a "weed twister."  There have also been several other products that feature a twisting motion for cultivation but not necessarily weeding.  The twisting concept in weeding and cultivating seems to have caught on in the consumer market!

One competing weed twister is made by Hastings.  This tool has four straight tines in a parallel array.  The tines have a length of about 4 inches and are arranged like a square when observed from the pointed ends.   Although this tool is nominally designed for twisting, the tool does not have the coil shape of the Ergonica Weed Twister to allow for efficient penetration and twisting into the soil.  We have also recently observed that the Hasting website is not functional at this time, which may mean that the tool is no longer available.

OTHER HAND TOOL DESIGNS

We have noted a few interesting alternatives but none that we believe may be of value to this discussion in the agricultural setting.  For example, one tool has several nail-like tines that are intended to surround a dandelion plant and grab the entire plant when a foot lever is pressed.  This is a rather heavy and clumsy tool and can only be applied to weeds with short roots of no more than three or four inches. 

Another extreme is a super-large wrench device that can effectively remove fairly large plants as tall as several feet.  For the agricultural scenarios in California, this size of weeds is not anticipated.

There is also a motorized twisting tool shaped like an extended paint-mixing prong.  This design has some potential advantages, but the disadvantages appear to be out of balance.  In addition to the weight and cost of a separate drill-type motor tool, once the weed is removed by the tool, the weed is usually wrapped extensively around the prong, requiring a lot of work to unwind the weed.  If the prong does not hit target, the result will often be a broken plant stem.  This tool may potentially work better when combined with a motorized rotating accessory that is specifically designed for this purpose.  This accessory would feature a slower speed than most power drills allow and an easy way to reverse the direction to unwind the entangled weeds.  We would encourage inventors and manufacturers to continue working on the development of a motorized twisting tool.  The Weed Twister patent also includes a motorized version which has not yet been developed for commercial production.

HERBICIDES AND REGISTRATION

The Weed Twister does not require registration for any crop as needed for dangerous herbicides such as ethofumesate, prometryn, ethalfluralin, edothall, Stinger, metribuzin, Casoron, Flex, flumetsulam, Kerb or Visor, to name a few.  Safety and vigorous growth for all crops, workers and the ecology is protected and enhanced by the Weed Twister, beyond the capability of any chemical to date as well as many other mechanical applications.  Register the label for the Weed Twister as "safe and healthy" for all crops including carrots, onions, celery, strawberries, grapes or peppers as well as yourself, your family, workers, pets, bugs and worms. In the era of sustainable agriculture, the question is: "Are there new methods and tools suitable for sustainable agriculture?".   Many innovative and suitable solutions today have not been evaluated or tested appropriately by large corporations, traditional experts, farm advisors and master gardeners.  Forward-looking growers may find it profitable to take part in testing new tools, such as the Weed Twister, along with other biodynamic and permaculture methods.  

ERGONICA WEED TWISTER TECHNIQUES FOR AGRICULTURE

Several techniques and options for using the Ergonica Weed Twister are more appropriate for agriculture than for home consumer use.  An exhaustive list of home consumer techniques and applications can be seen on the Weed Twister website.    For agriculture, an efficient, ergonomic set of techniques is necessary.  These techniques are based on the premise that the agricultural worker may be called upon to remove weeds for several hours in one day.  An ergonomic design becomes more critical when fatigue and repetitive motion are anticipated.  Not only can the Weed Twister be applied to open furrows, but it is also effective in nursery containers of various sizes due to the Weed Twister's exceptional precision.  For using the Weed Twister to remove lawn weeds and a variety of other domestic applications, please review the Weed Twister Instructions site.

Hoeing, Hooking and Twisting

The new worker should be given a thorough orientation on how to safely and efficiently hoe, hook and twist with the Weed Twister.  This orientation will greatly increase efficiency and reduce strain and effort for the worker.  In the game of poker you have to know when to hold them or fold them.  When using the versatile Weed Twister, you have to know when it's best to hoe, hook or twist, depending on the weed type, size and shape as well as soil conditions.  Much of this judgment process can only come from the worker's experience with specific crops and specific weeds and soil conditions.  Because of this judgment process, there will very likely be a number of workers who enjoy superior performance than other workers.  These Expert Weed Twisters may become the trainers to orient new users of this tool.

Hoeing with the Weed Twister has been presented in previous tool comparisons.  The decision to hoe with the Weed Twister is based on the identification of small weeds with shallow roots.  Another factor will be the condition of the soil.  Soil that is more compacted may not lend itself to hoeing by the Weed Twister.  In most cases, however, small growths of new weeds with roots as deep as 2-4 inches or so can be easily and precisely unearthed by sliding the Weed Twister in a pulling (not twisting) motion much like the application of a  traditional flat-edged hoe.  When small weeds are growing in tight areas between furrows, for example, the circular edge of the Weed Twister can be safely extended to unearth these intruders.  For larger areas where precision is not as critical, other less precise hoes may be used to cover more ground with less effort.  Small weeds with no flowers or seeds can safely and efficiently be unearthed in this manner with no concern about removing the debris from the ground.

Hooking is appropriate for slightly larger weeds with larger root systems.  Whereas hoeing involves a pulling motion towards the worker, hooking involves sliding the tool sideways from right to left to take advantage of the clockwise spiral of the coils.  Hooking is more of a jabbing and grabbing motion in soil depths of about 3-6 inches.  When you look at the coils of the Weed Twister from different angles you can see a circle, a hook or a spiral shape.  Likewise, the effective action of the tool can change when applying it from different angles and with different motions.  This is where training and experience come into play.  Some users immediately "see" the engineering and geometric potential of the Weed Twister at a glance.  It's like love at first sight!  Others require more training and practice.  The skill in hooking is knowing when it's appropriate and how to orient and move the tool towards the target.  When the soil is relatively loose, it's fairly easy to push the coils as a hook beneath the main root system and pull out the entire plant with very little, if any, twisting.  Hooking is also an effective method to remove larger weeds in nursery containers depending on the size of the container and proximity to the crop plants.  The 2-inch precision is ideal for protecting valuable plants in containers.  In larger containers, the hoeing method may also be effective. 

Twisting is the classic motion reserved for larger weeds and deeper roots.  These are plants with roots that need to be fully engaged in the coils in order to be twisted and detached from the soil.  Twisting is the most efficient method for loosening larger root structures from the soil without rupturing the central core of the roots.  Other tool designs require either digging a large hole or carefully poking prods into the roots in a hit-or-miss fashion to eventually free the root structure from the soil. Once the root filaments have been loosened from the surrounding soil, the entire plant will begin to rotate more freely along with the Weed Twister shaft.  The Weed Twister Waltz, as described above, is an efficient and graceful method of lifting the weed off the ground.  The user will feel a reduction in resistance against the twisting motion when the weed is ready for lift off.  At this point, it is safe to simply lift the tool and the entire root system and plant will follow. 

Twisting requires less lateral space than either hoeing or hooking and therefore can be applied safely to horticultural containers or narrow spaces where weed roots have grown to greater depths.  Even when weeds are immediately next to the crop growth, or intermixed, the twisting method can safely be applied.  Since no soil is thrown into the air with the twisting motion, in contrast to the traditional blade hoeing motion,  there is little danger of accidentally dusting the crop with soil.  Twisting can also safely be applied underneath grape vines and other large plants, vines, trees and cacti on plains and hillsides because of its precision and because no rapid hacking is used as with the motion of the traditional hoe.  In many cases, twisting can safely be applied underneath plastic mulch, covers and netting by using the coils to partially lift the covers and reach directly into the weeds.

Twisting is also the most effective method for removing branched root systems such as those of grasses, like St. Augustine grass, for example,  and other plants with networked roots.  The coils can be used to look or 'fish' for unseen roots by twisting and hoeing into suspect areas where visible weeds have been removed.  Once found, these roots can be snared and removed by the twisting motion.  Even if some root parts remain, by periodically twisting and hoeing in the same area the weeds will ultimately be completely removed.

Removing the Plug and Debris

Twisting or hooking normally results in the deposit of a plug of soil in the center of the Weed Twister coil along with the entire plant that was removed.  In home gardens, the gardener will usually grab the debris with the free hand and tug it out of the coil.  If a rock, tree trunk, tool handle, or other hard surface is nearby, tapping the coil against the hard object will cause the plug to loosen and the rest of the debris will usually fall off by gravity or gentle pulling.

Tapping a hard surface to remove the plug presents a minor logistical issue in an agricultural setting where hard surfaces are generally not found.  If a standard hoe is nearby, however, the wooden handle of the hoe will make an excellent tapping object.  Otherwise, an accessory object with a hard surface will be needed to take advantage of the tapping technique. 

Accessories

The optional accessory tapping object may take any of several shapes.  For example, a simple piece of wood may be placed on the path on which the user is working.  This piece of wood may be a few feet in length and may be moved ahead of the worker every few minutes.  Another type of tapping object may be a hard surface strapped to the worker's boot and / or shin.  For ergonomic protection, a shin guard or safety boots may be used to support the tapping object.

It should be noted that even without these tapping accessories, it is not difficult to grab the debris in the coil of the Weed Twister and remove it with a simple tugging motion.  The tapping objects should be viewed as optional accessories to increase the efficiency of a system that is inherently more efficient than other alternatives currently available.

The Weed Twister is light enough to hang on a tool belt or harness worn by the worker.  A special belt or harness may be configured to hold the Weed Twister when not in use as well as other small tools and helpful objects and supplies such as gloves, knee pads and water bottles, for example.  A harness may also be used to strap the Weed Twister on the back of the worker where it can be reached over the shoulder.  The Weed Twister is lighter than most hoes which allows the worker the option of safely holding it in one hand while handling other objects.  It can also be temporarily planted into the ground with a screwing motion to allow the worker to use both hands for other tasks.  

The following table describes the comparison between the effectiveness of various hand weeding tools described in this paper:

Hand Weeding Tools Effectiveness by Features, Root Types and California Regulations

* Hand weeding is allowed when there is no readily available or no reasonable alternative means of performing the work that is suitable and appropriate.
Note: The evaluative terms in this chart are descriptive and judgmental and are not presented as standard terms.  The author's evaluations are explained in the preceding text.

FUTURE DEVELOPMENTS

The U.S. Patent and Trademark Office eliminated the category of weeders in their classification system years ago.  But that didn't discourage many creative inventors from coming up with new weeder gadgets and occasionally acquiring patents, such as the Weed Twister (Patent No. 5,441,118),  to the benefit of the increasing number of gardening enthusiasts and farmers.  (To view images of patents on the USPTO website, the Netscape Navigator browser may be necessary.)  With the advent of alternative hand weeders in agriculture, there may be a renewed interest in developing new products of this type.  The laser weeder or the robo weeder may not be that far off in the future.  Preliminary designs may already be on the drawing boards.  Ergonica may also develop the motorized version of the Weed Twister as was claimed in the original Weed Twister patent, if the demand for such a tool becomes evident.

In the meantime, the developers of the Ergonica Weed Twister intend to support the study of hand tool alternatives to hand weeding, the short hoe and herbicides in California agriculture.  Continued testing will add valuable insight regarding the specifications for ergonomic tools and the best ways to apply technologies and tools that are currently available.  Testing should be conducted on many different crops and weeds and various soil conditions for results that are more useful to the majority of growers in California. 

California enjoys some of the most productive agricultural counties in the nation, including Fresno County, Tulare county and Monterey County, which are the top 3 counties nationally.  Each of these counties produced more than $2B in agricultural sales as recorded in the 2002 census.  Monterey County also stands out as one of the top 3 berry producers in the nation with over 12,000 berry farm acres.  Methodical testing should be conducted in all of these counties and wherever precise weeding is required.

For a more objective scientific analysis,  the UC Cooperative Extension will continue to play a very important role in coordinating these studies and recording their results.   Growers have stated that costs of hand weeding can extend to as much as $1,500 an acre.  Scientific studies and a cost-benefit analysis are needed to show whether mechanical hand weeding aided by some of the tools identified in this article and other alternatives can significantly lower these costs.  Any significant reduction could result in savings of perhaps millions of dollars to agribusiness in this state.  Interested parties should contact the UC Cooperative Extension representatives in your area.  To find out about upcoming hearings on the emergency regulations visit the Cal OSHSB (Occupational Safety and Health Standards Board) website.  You may also contact Ray Cruz, the inventor of the Weed Twister and author of this paper, at ray.cruz[AT]ergonica.com, for more information about upcoming tests involving the Weed Twister.

On January 27, 2005, OSHSB released the latest revisions of the Hand Weeding Regulations.  These revisions do not significantly alter the emergency regulations previously released. 

See the Ergonica Press Release page for the latest Ergonica updates.

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