December 5, 2019

Goodbye herbicide, hello weed-zapping farmbot

The UK’s Small Robot Company and RootWave partner to develop a non-chemical weed control

Maija Palmer

4 min read

Farmers may soon have an alternative to spraying their fields with chemicals, as Small Robot Company and RootWave, two UK-based agritech startups, today announced a partnership to develop a high-precision robot that can kill weeds with a zap of electricity.

Small Robot has already developed a series of small, agricultural robots, called Tom, Dick and Harry, which can automate some of the routine tasks of farming. Tom, a scouting robot similar to the Mars Rover, for example, uses computer vision to map the weeds in a field, covering about 20 hectares a day.

Dick, a weeding robot, can already remove unwanted plants with either a micro-dose of pesticide or by physically crushing them, but the next stage will be to combine this with technology from RootWave, which destroys weeds by with an electric current, essentially boiling them from the inside out.


“Farmers are really desperate for an alternative to the chemical control of weeds,” says Sam Watson Jones, the chief executive of Small Robot Company. “Existing chemicals are becoming less effective against weeds and we are seeing bans on the use of chemicals such as glyphosate.”

Tom, the scouting robot, can map weeds in a field and cover 20 hectares a day

Some experts suspect that glyphosate, the ingredient in Monsanto’s Roundup, causes cancer in humans, and as a result it has been banned in countries, such as Austria, the Czech Republic, Italy and the Netherlands, and will be phased out in Germany and France from 2023

“The trouble is there isn’t really a good alternative to glyphosate,” says Watson Jones. Ironically, glyphosate is one of the safest of the general-purpose herbicides available — most others have already been outlawed as much more dangerous. Mechanical weeding (i.e. hoeing) on the other hand doesn’t always get rid of plants effectively and can be damaging to the soil. Destroying weeds with lasers or jets of hot water, meanwhile, takes a lot of energy and can be expensive.

Electrical weed zapping can be as cost-effective as using chemical herbicides, working out at around six euros per hectare, says Andrew Diprose, chief executive of RootWave.

The two companies, which have received grants of more than £1m from Innovate UK for the project, are planning to have a system available for commercial trials by autumn 2021.

If successful, the weed-zapping robots could be a challenge to the $26bn a year global herbicide market that is dominated by big companies such as Bayer (owner of Monsanto), DowDuPont, BASF and Syngenta.

A number of precision weeding startups have emerged to challenge the conventional spraying model, including Ecorobotix, a Swiss startup that uses computer vision to detect weeds, delivering a small dose of chemicals just to the unwanted plants. This kind of system already uses 20 times less herbicide than conventional methods, Ecorobotix estimates.

Denmark’s Agrointelli is also developing farming robots that can deliver precision doses of herbicide, while Naio Technologies in Toulouse is building robots for mechanically weeding large-scale vegetable farms.

RootWave has partnered with Steketee, the Dutch agricultural equipment company, to develop an electric weed zapper that can be pulled along by tractor.

A combined RootWave and Small Robot weeder, however, would be the first time that robots could weed using electricity.


Big agrochemicals companies are taking note of the precision trend, too. Robert Bosch has been working with German chemicals company BASF for the last three years on a smart spraying product they hope to bring to market in 2021. In 2017 US tractor company John Deere bought Blue River Technology, a computer vision and precision spraying company, for $305m. But many of these are still geared around the use of very large tractors.

A bigger revolution in farming will come if the industry can move towards using smaller machines. Not only would this make it more economically viable to farm on smaller plots of land (much of Indian agriculture, for example, is based around very tiny farms) but they would allow farmers to use techniques that use less water and cause less soil erosion.

“We are at the start of what will be the fourth agricultural revolution,” says Watson Jones. “We will see a move to per plant precision in agriculture, and swarms of smaller machines doing the work. It will completely change the way we grow food — and it could even change the way the countryside looks.

“We’d no longer need large fields of monocultures because that is the most efficient way to use big farm machinery. We could grow multiple species in the same field, in ways that massively reduce water use and carbon emissions.”