Farm Progress

Weed-Whacking Robot

Developers plan to take their new Lettuce Bot into corn fields next.

Peg Zenk 1

January 19, 2013

2 Min Read
<p> Pulled behind a tractor, the Lettuce Bot photographs seedlings and eliminates those that are too close together using a squirt of concentrated liquid fertilizer. The same computer vision technology will be used in a second version that eliminates weeds in corn fields.</p>

What started as a high-tech machine for thinning lettuce could easily be transformed into an effective alternative for herbicide-free weed control in Midwest row crops. The Lettuce Bot, developed by Stanford-trained Engineers Jorge Heraud and Lee Redden, is expected to hit the market in 2013 and provide an economical substitute for human laborers who now have to thin the billion-dollar California crop by hand.

“It’s very hard work and field laborers are also in short supply, so our machine is a very cost-effective alternative to fill the gap,” says Heraud, who worked for Trimble Navigation’s agriculture group prior to joining Redden to found Blue River Technology in 2011.

The duo’s first-generation system is pulled behind a tractor and uses computer vision and robotics to thin rows of lettuce when plants are just a few inches tall. Taking pictures of the passing plants, the shielded device then compares them with a database of more than a million images, taken from a variety of angles. Plants identified as being too close receive a squirt of concentrated fertilizer, which kills the unwanted lettuce seedlings and, at the same time provides nutrients to those remaining.

The Lettuce Bot certainly speeds the process – it can thin a row four times faster than a hunched-over human can, and takes eight rows at time.

The same basic technology should convert easily for row crops, such as corn, says Heraud. “Corn plants look very different from many of the most common weeds, so it should be fairly simple to develop accurate identification of both. If our eyes can see the difference, then our system can, too.”

When a weed is detected, a little mechanical system – probably with rotary blades – would be triggered to instantly take it out. “This type of system would have broad appeal not just for organic producers but where weed resistance has become an issue,” he says. “It could also be used to produce non-GMO crops for countries that don’t allow them.”

Once Lettuce Bot enters full production, the research team will focus on developing and field-testing a weed-whacking version, he adds. “Right now, we are shooting for a prototype for corn developed and in testing in 2014.”

The cost of such a “Weed Bot” would be affordable and well in line with existing ag equipment alternatives, says Heraud. “We need to work at improving the durability of the components, but that shouldn’t be too difficult.”

In September, Blue River Technologies, Sunnyvale, Calif., secured investor funding, which should help it get its Lettuce Bot to market. “That capital has allowed us to grow our engineering team and accelerate product development,” adds Heraud.

To learn more about Blue River Technologies, visit

Subscribe to receive top agriculture news
Be informed daily with these free e-newsletters

You May Also Like