HAR-e, the autonomous harrow
The HAR-e was developed purely for harrowing and not for attaching other machines. It is a lightweight machine that minimizes soil compaction. The machine operates autonomously via GPS and can run 24 hours a day, reducing the chances for weeds to develop.
In the summer of 2024, FieldWorkers introduced the HAR-e, the first full-field operating precision harrow. The manufacturer has since given many demonstrations. “Every organic grower uses a harrow to reduce weed pressure. While selling our small weed beds to growers, we heard that harrowing actually happens too infrequently. It’s a labor-intensive process that’s hard to schedule during the busy season. That was our reason for developing a robot purely intended for harrowing all organic vegetables. Onions are the most important crop for this, because that’s where the machine’s investment can be earned back most effectively through labor savings,” says Koen Hertogh, co-founder of FieldWorkers, a company that makes agricultural machinery for organic farming.
“In addition to the electric HAR-e harrow, we also make small weed beds for two-person weeding, and we’re known for the Colorado Beetle Catcher, a machine that removes Colorado beetles from potato fields and is also sold in the United States.”
Endless operation
The advantage of the HAR-e is that it can continuously harrow, giving weeds far less opportunity to grow. The machine operates autonomously via GPS and can run 24 hours a day, allowing it to compete with larger conventional harrows. “Thanks to the solar panels on the roof, the machine can keep running indefinitely,” says Hertogh. “The panels charge the batteries enough during the day to continue operating at night. So charging at a station is not strictly necessary.”
The solar panels on the HAR-e are not flat, but tilted upward. This is not to capture more sunlight, but because the builder wanted to give the robot a better ‘look.’ The HAR-e is fully autonomous and can be controlled via a smartphone or with a remote control—intended only for driving the machine from the shed to the field. The robot is also in use at Wageningen University & Research. “We want to demonstrate the difference in weed pressure and crop yields between robotic harrowing with the HAR-e and traditional harrowing every one, two, or three weeks,” Hertogh explains.
Variable speed
The HAR-e’s capacity varies depending on the crop stage and weed pressure. “If, for example, small onions are still very young, the machine drives at 0.5 km/h. But when the onions are larger, the HAR-e can reach a speed of 5 km/h. In theory, the electric harrow can then achieve a capacity of 1.8 hectares per hour. Another advantage is that the HAR-e weighs only 1,500 kg, which reduces soil compaction. If you work with a 12-meter harrow, you need a large tractor, which causes more compaction.”
On the headland, the two-wheel-drive HAR-e robot can turn sharply with a steering angle of more than 60 degrees, meaning only a narrow headland is needed to turn the robot. The HAR-e can move to the next pass via different types of turns or by maneuvering in a Y-pattern. The entire combination of robot and harrow costs about €75,000. “Our machine performs well, and we’ve already sold a HAR-e for 2026 to a customer who will put it into practice. Our goal is to scale this up further.”
