With higher labor costs and more incentives to grow organically, European farmers are increasingly turning to robotic weeders.

The Robovator, for example, is a vision-based hoeing machine that finds and eliminates the weeds found in row crops. Another cultivating machine, the Steketee IC Weeder, uses camera images to calculate plant position.

Throughout 2015-16, Steven Fennimore, an extension specialist at the University of California, Davis, brought the Robovator to organic and conventional fields containing specialty crops like celery, herbs, and sweet potato.

With support from the university lab, Fennimore and his team took the robotic weeder to farms throughout coastal California, Salinas, Santa Maria, Oxnard, and the San Joaquin valley.

Fennimore told Tech Briefs that the tractor-towed Robovator – a technology from the Denmark-based F. Poulsen Engineering company – improved weed control by over 30-40 percent compared to a standard cultivator.

The Robovator (Image Credit: F. Poulsen Engineering)

Automated weeders aim to take out the troublesome plants without damaging valuable lettuce, bok choi, and other crops. Unlike standard cultivators, the Robovator, as well as the Steketee IC, work within the seedline, as long as the crops are spaced at least 5-6 inches apart.

A robotic weeder contains a camera to detect the row pattern. Additionally, a speed sensor provides the machine alignment, and an actuator chops out the unruly growths with a blade.

The Robovator “sees” that the crops are planted in neat columns, and the weeds are randomly scattered – an imperfect recognition rule, Fennimore admits, when there are a heavy number of weeds.

Judging a weed from a crop requires the grower to be very exact when using the technologies.

“The rows have to be a little straighter, cleaner, and more consistent because the machines aren’t that sophisticated yet,” said Fennimore in a recent news release from the American Society of Agronomy. “The robots don’t like surprises.”

So, why haven’t we seen more robotic weeders on U.S. farms? The technology is currently expensive, says Fennimore, between $120,000 and $175,000, and there is a wait-and-see approach, as technology improves and more competition enters the market.

The robotic weeders address two challenges for farmers, says Fennimore. First: herbicides, which are sometimes unavailable for specialty crops.

Additionally, herbicides require a lengthy registration process. If you want a new herbicide for lettuce, for example, you need proper authorization and must follow specific regulations.

“With intelligent cultivators we can operate in organic and conventional fields, and the only permission we need is from the grower,” Fennimore told Tech Briefs.

Secondly, technologies like the Robovator may provide a better long-term option than expensive hand-weeding – a slow process that costs between $150-$300 per acre.

Fennimore, who presented his research at the October Annual Meeting of the American Society of Agronomy, in Tampa, FL, is currently working and experimenting on systems to better differentiate crops from weeds.

Franklin Robotics, based in Massachusetts, is also introducing a solar-powered, weeding bot for home gardens – called Tertill. The technology is available for pre-order, but a production date has not been set.

What do you think? Will we see more robotic weeders on farms? In our own gardens? Share your comments below.