The world's population is expected to grow from about 7 billion to over 9 billion by 2050. That's means we're going to need more food. A lot more food.

To grow it, the world's farms must increase production by about 60 percent, according to a report published last year by the World Resources Institute. That's a tall order, made taller still when you consider that researchers expect shortages of water, fuel, fertilizer, and arable land to make it even harder to meet growing demands.

But Rory Aronson and his Farmbot are here to help.

Rory Aronson, founder of Farmbot. Image: Farmbot

One way to address our farming challenges is through practices collectively known as precision agriculture. Precision farmers use technology like self-steering tractors and aerial drones to more efficiently use water, fertilizer, and other resources. They can give plants precisely the right amount of water, for example, or apply pesticides only when and where they're needed. These techniques aren't a cure-all for the challenges we face, but a study by researchers at Purdue University and the National Institute of Agricultural Technology in Argentina concluded that precision agriculture can play an important role in sustainable farming.

Most precision agriculture tools are sold to industrial farms, but Aronson is taking a different tack with Farmbot. It's an open source machine, meaning anyone can take the design and build their own. Aronson believes it can help bring precision techniques to small-scale farmers – beginning with home gardeners. "I'm hoping for our prototype to be under $1,000," he says. "The first model will be targeted at the 'geeky gardener,' someone who has always wanted a garden but maybe they don't water it enough and they want a geeky toy to help them."

He dreamed up the contraption in 2011 as a student at Cal Poly in San Luis Obispo, California. He was studying mechanical engineering, but, to satisfy his interest in gardening, he took an elective in organic agriculture. One day, a farmer gave a guest lecture about a tractor that used machine vision to detect and pull weeds, eliminating the need for either manual labor or environmentally damaging herbicides. The only problem was that it cost more than $1 million.

That gave Aronson the idea of doing the same thing with a series of tracks and pulleys that operated more like a dot matrix printer than a tractor. Instead of using machine vision to "see" weeds, this contraption would know the exact position of all its crops, so that it could pull-up everything around them. He quickly realized this would be cheaper than the tractors, and that it could be used for other tasks as well, like planting and watering crops.

Last year, he published a white paper on the project and quickly attracted a team of volunteers, including software developer Rick Carlino and firmware hacker Tim Evers. The team is almost done with its hardware prototype, and it will then work on software that will include a "gamified" interface for managing the garden. Aronson compares this interface to the popular online game Farmville.

Starting next month, Aronson will be working on the project full-time, thanks to a grant from the Shuttleworth Foundation, the nonprofit organization started by Mark Shuttleworth of Canonical, the company behind the Ubuntu distribution of Linux. "I imagine I will create a for-profit company to sell hardware kits," Aronson says. "What's awesome in my eyes is that everyone can start a business related to Farmbot. Plugins, seed injectors, anything."

He says other companies could even compete directly with him by selling their own kits – an idea he welcomes. "The point at which some other business is selling it – that would be the first sign of success," he says. "The point I can step away from the project and it would be self-sustaining is when I will consider it successful."