The world's biggest commercial rooftop greenhouse sits atop a former Sears warehouse in a semi-industrial northwestern quarter of Montreal. Early every morning, staff pick fresh vegetables, then bring them downstairs, where they get packed into heavy-duty plastic totes along with the rest of the day's grocery orders. Whatever Lufa doesn't grow in its four greenhouses comes from local farms and producers, mostly from within 100 miles. This is a modern foodie's dream: a tech-forward online shop full of locally grown, pesticide-free, ethically-sourced products at reasonable price points, delivered once a week to either your doorstep or a local pickup point in your neighborhood. Customers - Lufavores, as the company calls them - typically place their orders a few days before delivery through the online store, dubbed "the Marketplace," which Lufa built from scratch in 2012. That's how Lufa's suppliers know how much product to provide: They get forecasts first, then final order numbers, through their Lufa software. Technology is the underpinning of Lufa's success, and the owners know it. "We see ourselves as a technology company, in the sense that we solve with software," [cofounder Lauren] Rathmell, 32, says. "Nothing off-the-shelf can be applied to what we do, because it's so complex. We harvest food ourselves; we gather from farmers and food makers throughout the province; most of it's arriving just in time throughout the night to be packed in baskets for that day, and every order is fully unique."