Eco-Weeder (Puzzy Boy)
The Device & How it Works
|Click the images to see the effects of the Eco-Weeder! (Note that the centers survive.)|
Forevergreen™ states that results are instantaneous, but that previously untreated areas must be treated more frequently at first to be effective. Once a maintenance program has been established, however, these areas can be treated less frequently. They recommend that dry weather and a low degree of relative humidity are the optimal conditions for using the Eco-Weeder, but wet, rainy conditions are also acceptable. Forevergreen™ adds that the Eco-Weeder can control all weeds, but deep-rooted plants will require repeated treatments to achieve full kill.
Eco-Weeders are produced in a variety of different sizes (and prices) ranging from the smallest (the Punto model) for homeowner use costing $225.00, to the largest (the Agri IV model) for agricultural use. The models with wheels can be operated at approximately 1.5 km/hr (1 mph), and stationary machines take about 1.5 seconds to spot-treat a single small plant. It costs about 2 cents to operate per 9 square meters (100 square feet). The Eco-Weeder can be used on many types of surfaces, including stone, paving, gravel walkways, earth and concrete.
A Field Test
I used the Agri Ronco model, which according to Forevergreen™, has an effective width of 200 x 300 mm, uses 0.5 kg/h of gas consumption, outputs 7.8 kW/h, and weighs (without the gas tank) 5.0 kg (11.9 lbs). I measured our infrared plate area to be 135 mm x 365 mm, the propane tank mounted on the backpack to weigh 6.8kg (15 lbs) and the unit with the wheel mounted in front weighed 13.6 kg (30 lbs). This unit was purchased for $1,555.00.
|Dr. Tu looking casual with her Eco-Weeder|
According to Forevergreen™, it is not necessary to blacken or incinerate the plants for good kill results, only to turn the foliage dark green--indicating that the cells themselves have exploded. It was difficult for me to tell when sufficient kill was achieved, especially on grasses and sedges. On small seedlings and prostrate plants, the Eco-Weeder performed well, achieving full kill within 30 seconds or so. On perennial plants with a deep taproot or extensive rhizome system, it is unlikely that the plants were severely negatively affected after one treatment. It was difficult to kill the center of the plant (with a deeply buried apical meristem) in perennial or biennial herbs with a basal rosette of leaves, even after a 1.5-minute direct treatment with the Eco-Weeder. In addition, grasses or sedges with any litter material accumulated from past years' growth, may have enough insulating material to protect them from the Eco-Weeder. I found that even after a direct treatment of over 1.5 minutes per plant, that sedges, bunchgrasses, and herbaceous perennials may not have been fully killed by the Eco-Weeder. In order for the Eco-Weeder to be effective against tall plants, the plants will need to be mowed very close to the ground and the surface litter will have to be removed prior to treatment.
While Forevergreen™ advertises that their Eco-Weeder is fast and efficient, I found that it took between 10 to 15 minutes to adequately cover a 1 square meter area of low-lying perennial prostrate weeds. I may have been taking more time than necessary at each spot to achieve full kill, but it appears that at this rate it would take several days to treat 1 acre of weeds. On perennial weeds with large taproots or extensive rhizome systems, the Eco-Weeder Agri Ronco model may be less efficient. How well this device actually works on perennial weeds with repeated treatments, remains to be determined. Results will be reported here, within the next year or so.
Sidenote: TNC-Oregon had originally purchased the Eco-Weeder and was sent the device with the assembly instructions in Swiss. The propane attachment of the Eco-Weeder was not readily compatible with standard U.S. propane tanks, and was finally ready for use after obtaining the accompanying propane tank and a few missing attachment parts (which had to be sent from Switzerland). This entire process took several months. Furthermore, paint near the heating element of the Eco-Weeder began to peel-off following only 30 minutes of use.
The Hot Lower Surface
Advantages of the Eco-Weeder
- No permits are required for use.
- Can be used in areas where there is little or no fine fuel to carry a prescribed burn.
- Can be used in wet or moist conditions (even when raining!), but works best in dry, low humidity conditions.
- It is very specific--it can be applied to a single plant, with little or no disturbance to the surrounding vegetation.
- Proceeding carefully, a single person can use the Eco-Weeder to treat a weed-infested area.
- Seedlings or small, prostrate, broadleaf herbs are easily killed. Works well in sidewalk cracks or in small areas.
- Little fuel used, no residual chemicals left in soil.
Disadvantages of the Eco-Weeder
- An Eco-Weeder, especially a model of sufficient size, can be very expensive.
- Smaller models may not effective in wildland settings, where there may be much accumulated leaf litter.
- Does not work instantaneously for deep-rooted plants or for herbs with a basal rosette protecting the apical meristem; may kill these plants after repeated treatments.
- Mature bunchgrasses, rhizomatous grasses, and sedges are difficult to kill.
- Damage to native biological soil-crust organisms may be significant.
The Eco-Weeder is a handy (but expensive) device for controlling seedlings or prostrate weeds, especially along sidewalk cracks or in flat, bare areas. It might be very useful in removing weeds from around preserve visitor centers and parking areas. Its utility in wildland settings is limited, especially, where weeds are large, occur in areas with much litter, or are deep-rooted perennials.
For information on different models, specifications, and purchasing, see the Forevergreen™ website at http://www.chemfree-weedcontrol.com. For personal account information on the Eco-Weeder Agri Ronco model, contact Mandy Tu (TNC-WIST, imtu(at)tnc.org, 503-230-1221)
Debbie Pickering (TNC-Oregon, dpickering(at)tnc.org, 503-230-1221).
--Mandy Tu & Barry Rice, TNC/GIST, January 2002