Green Roof Technology

A unique mechanized greenhouse operation delivers its first crop of salad greens, herbs and spinach and begins to pay back a $2-million investment. 

This greenhouse, perched over a parkade in downtown Vancouver, employs a four-meter-high system of hundreds of suspended trays that move to maximize exposure to natural light and to facilitate harvesting.

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Alterrus’ vertical greenhouse prototype has been operating in a greenhouse at England’s Paignton Zoo for three years, providing food for the animals. But all eyes are on Vancouver to see if the system can turn a profit as a standalone business, according to the company’s strategic adviser Donovan Woollard.

The Vancouver-based company, which trades on the Canadian National Stock Exchange and has a market capitalization of $9.5 million, went back to the market for $500,000 in operating capital earlier this year.

Alterrus showed an operating loss of $417,453 for its most recent fiscal quarter and on its balance sheet, the company states it has accumulated $53 million in losses during its development stage.

“Our priority is to show that this is a viable way to grow food,” said Woollard. “We’ve already shown that VertiCrop can grow produce.”

The parkade greenhouse — built on a 6,000-square-foot space it leases from the City of Vancouver — is just a short bike ride from its prized customers, grocer Urban Fare, and high-end restaurants such as Cioppino’s, Hawksworth, Boneta and farm-to-table concept restaurant Fable.

That proximity is vital because downtown customers will take delivery of their orders from Shift Urban Cargo, a bicycle-based delivery firm. By serving clients within a few blocks of the greenhouse, lettuce can go from greenhouse to plate within hours.

“I like the idea of fresh urban foods right next door,” said Cioppino’s chef Pino Posteraro.

By building upwards in vertical arrays, the Alterrus design effectively turns one square metre of greenhouse into four and produces about 20 times the food of a similarly sized field, Woollard said.

The company’s branding trades heavily on sustainability and the local food zeitgeist, selling produce under the brand name Local Garden.

“It used to be that 80 per cent of what we ate was grown locally, so we are trying to directly replace imported produce from 1,500 to 2,000 kilometres away,” said Woollard. “The way we operate also employs a broader social purpose.”

Alterrus recently won B Corp status, a certification for sustainable business practices. “We are the first publicly traded company to achieve that,” Woollard said.

Plants grown in the VertiCrop system use about eight per cent of the water required for typical California field crops. All the nutrients used in the soilless cultivation system are recovered rather than leaching into groundwater or washing into streams.

Greenhouse workers who pick, wash and pack produce are hired through Mission Possible, a local non-profit agency that helps people find jobs after extended periods out of the workforce.

Most of the greenhouse’s power consumption needs for lighting, temperature control and mechanical operations are satisfied by hydroelectric power, with a minimal carbon footprint.

In addition to their commercial clients, Local Garden greens will be made available to customers of, a firm that specializes in home-delivered organic and local sustainable foods.

Greener Cities is a division of Crossbow Communications. We are developing Greener Cities as a resource for sustainable and resilient cities and communities around the world. We seek best practices, case studies, significant announcements and collaboration.