The Salinas Valley is getting a lot of attention from Silicon Valley lately. A new tech incubator will soon open up in downtown Salinas hoping to grow the connection between agriculture and technology.
But even before that, one Silicon Valley start-up was already hard at work tweaking its version of a machine that thins lettuce plants. It’s a job normally handled by human hands. But this may be just the tip of the iceberg in a new era of smart machines in agriculture.
To understand this smart machine, you first need to understand how lettuce is cultivated. “We plant extra to make sure we get a good stand, and then we go in and thin out the extra plants,” says Ron Yokota of produce company Tanimura and Antle.
On a windy summer day, Yokota surveys about a dozen farm workers in a lettuce field in the Salinas Valley. This is where most of the country’s lettuce is grown.
As they walk between the lettuce beds, they use hoes to pull out budding heads of lettuce to create room for the most viable plants to grow. This is called lettuce thinning. It’s a tedious job that requires a lot of quick decisions.
“That’s why these automated machines are so difficult to make because replacing a human and their decision capabilities out in the field, it’s not an easy task,” says Yokota.
But Yokota believes technology is the future. For one thing, he says the ongoing labor shortage means there are not enough people to do this kind of work. So Tanimura & Antle is trying out automated lettuce thinning machines in some of its fields.
And one, developed by a Silicon Valley start-up Blue River Technology, seems to be the most promising. It’s called a LettuceBot, and it makes the decisions about which plants will go and which will stay.
Blue River is not the first to automate lettuce thinning. It has competitors, and early efforts date back to the 1950s when Hewlett Packard tried to make a lettuce thinner. What’s different now is how technology has advanced.
“Very recently there’s been this revolution in how you can use machine learning and how you can apply it. These algorithms didn’t really exist 15 years ago,” says Lee Redden, a roboticist and cofounder of Blue River Technology.
The company’s other cofounder is Jorge Heraud, a veteran engineer from the navigation industry. The two met in a Stanford entrepreneurship program. Both have family farming in their backgrounds, but are techies first.
They initially started out with the idea of making an autonomous lawnmower, but switched to a lettuce thinning after talking to farmers. “So actually going out in the field and finding the lettuce thinning was a problem, a problem worth solving, so we didn’t start with a technology a look for something to apply it to, we started with a problem,” says Redden.
How It Works
The technology behind the machine’s decision making is similar to face recognition like on Facebook, only instead of recognizing your friends the LettuceBot recognizes lettuce.
“I’m pretty sure we have the biggest number of pictures of lettuce plants,” says Heraud, “We’ve looked at millions plants, and we’ve told our algorithms, here’s what a “lettuce looks like”, so our machine is just tremendously good at what lettuce looks like.”
The LettuceBot is pulled behind a tractor and can thin four beds at once. Information from cameras mounted on the bottom help it make billions of calculations per second selecting the best plant based on size, position and distance to its neighbor.
When the LettuceBot makes a decision, it hits the plant’s leaves with a precise spray of fertilizer killing that plant while nourishing the roots of the lettuce left behind.
“By just putting it on the leaves, it burns the leaves and kills the plant,” says Matthew Rossow, Blue River’s Field Operations Manager. “We’re just using a herbicidic application of fertilizer.”
“The technology is still in in infancy. Although I’ve seen a lot in the last two years, I can’t wait for the next two years to see how far we’ll be able to push this technology,” says Heraud. “I believe that in particular when it comes to yields we’ll be able to have a very meaningful impact on yields.”
Meaning not only will the LettuceBot thin a field quicker than its human counter parts, but by ultimately making better choices, the goal is for it to leave more viable lettuce in the field. So instead of a crew of ten people out manually thinning a field, there’s a crew of one or two operating the LettuceBot.
“It’s kind of the starting point of introducing commercial smart machines into agriculture,” says David Slaughter, a professor at UC Davis who has more two decades of experience in the area of sensors and automation in agriculture.
“Blue River is one example that we’re hoping will expand to do more of taking the menial tasks away. So that people can do higher level jobs of managing machines that do menial tasks. Rather than the people having to do the menial tasks,” Slaughter continues.
“There aren’t currently a lot of intelligent machines in agriculture because it’s really still a very challenging outdoor environment,” says Slaughter. Challenges like rain and unstable ground. But start-ups like Blue River are already solving some these problems.
In 20 years, Slaughter imagines a farm where we know the latitude and longitude of every seed planted. Then a smart machine will come along, and with biotechnology there will be a way the plants to communicate.
“"I’m thirsty,” or “I need some nitrogen fertilizer”, or “some bugs are attacking me.” So there would be this knowledge transfer,” says Slaughter, “We’re going to be able to essentially give the kind of care that you would give to a plant in your own garden to plants on this mass scale,” said Slaughter.
For now there are more immediate problems. “One of the problems with this lettuce is, it’s red, and red looks like dirt to a camera,” says Ron Yokota of Tanimura and Antle. That’s one of the reasons why he’s still using a hand crew in this lettuce field.
Blue River’s Heraud says they’re working on that. Starting by taking thousands of pictures of red lettuce. And Yokota doesn’t mind the wait.
“People kind of expect things to be overnight. Farmers don’t expect that,” says Yokota.