Shipping containers have been redesigned to become housing, offices and even health clinics, but now a startup in Tucson is transforming them into sun-free, soil-free greenhouses. Leaf lettuce from their test system shows they've got dark-green thumbs.
Verdant Earth Technologies has a plan to retrofit standard 20-foot shipping containers into mini farms. Each of their controlled environment agriculture systems -- or CEAs -- is fitted with five shelves, where the plants live. Instead of sitting in soil, however, the plants sit in a nutrient-rich solution that also works to irrigate them.
Cofounder and CEO Josh Hottenstein says they're experimenting with different artificial lighting options, including one that uses solar concentrators and fiber optics to distribute light from LEDs. "Plants don't need the full spectrum of light," he says. Solar concentrators allow them to get the right wavelength and direct it.
Each containerized growing system has hookups for water and electricity, sort of like an RV. Unlike RVs, though, the system can be set to run for a set period of time, taking advantage of a utility's off-peak hours to even out the electrical load. Because there is no soil, growing a head of lettuce uses just one percent of the amount of water as lettuce grown in an outdoor field.
"It's resource-efficient," Hottenstein says of the system. "It's getting the most out of the limited resources you have."
The idea came together about a year ago when Hottenstein and his grad school classmate at the University of Arizona Myles Lewis sought a way to combine advanced greenhouse mechanics and hydroponics in an enclosed structure.
Hottenstein has an IT background and Lewis specializes in horticulture. Their savvy business plan won a competition at the university's McGuire Center for Entrepreneurship last year. Verdant Earth was just chosen as a regional semifinalist in the Cleantech Open, a national competition to identify promising clean- tech startups.
All that tech packed into a shipping container sounds expensive, but Hottenstein says that because the process maximizes resources, he expects the cost to be competitive with commercial greenhouse structures, around $20 to $30 per square foot.
The cost of the produce will be competitive with organics, Hottenstein adds. Currently the startup is between the proof-of-concept stage and prototyping, working on getting test systems to several customers. From there, they plan to begin manufacturing the systems.
So they've got technology to grow plants efficiently without soil, in the dark...a la other certain, leafy illegal plants. Hottenstein tells me he's used to fielding questions about those.
"Like any technology, there's a double-edged sword we need to deal with," he says. "There are a lot of misconceptions as to what hydroponics is and what it is not."
For him, the goal is growing vegetables. So far, he says, their system can produce 2,000 heads of lettuce within a one-month period, compared to 90 days for the same amount from a field. Hottenstein says the lettuce tastes good and is already being used at
some fine dining spots in Tucson.
One thing I never considered is that in an enclosed, controlled growing space that has no sunlight or soil, the need for pesticides dips to zero. If this kind of tech can be scaled up for vertical farming in urban environments, perhaps we'll see a new kind of labeling that has more of a ring to it than "organic."
Image: Rendering of Verdant Earth's shipping container greenhouse system. Credit: Verdant Earth Technologies.