How urban farms can make cities more livable and help feed America.Grist  Matt Simon 14 Nov 2025 Metropolitan gardens and farms are extraordinarily powerful tools that can improve food security, lower temperatures, and create invaluable gathering spaces. If you've spent any time on a roof, you know that it’s not especially pleasant up there—blazing in the summer, frigid and windy in the winter. Slap some solar panels up there, though, and the calculus changes: Shaded from gusts and excessive sunlight, crops can proliferate, a technique known as rooftop agrivoltaics. And because that hardware provides shade, evaporation is reduced, resulting in big water savings. Plus, all that greenery insulates the top floor, reducing energy costs.

Long held in opposition to one another, urban areas are embracing elements of the rural world as they try to produce more of their own food, in community gardens on the ground and agrivoltaics up above. In an increasingly chaotic climate, urban agriculture could improve food security, generate clean electricity, reduce local temperatures, provide refuges for pollinators, and improve mental and physical health for urbanites, among other benefits. 

With relatively cheap investments in food production—especially if they’ve got empty lots sitting around—cities can solve a bunch of problems at once. Quezon City in the Philippines, for instance, has transformed unused land into more than 300 gardens and 10 farms, in the process training more than 4,000 urban farmers. Detroit is speckled with thousands of gardens and farms. In the Big Apple, the nonprofit Project Petals is turning vacant lots in under-resourced neighbourhoods into oases. “You have some places in New York City where there’s not a green space for five miles,” said Alicia White, executive director and founder of the group. “And we know that green spaces help to reduce stress. We know they help to combat loneliness, and we know at this point that they help to improve our respiratory and heart health.” With relatively cheap investments in food production — especially if they’ve got empty lots sitting around — cities can solve a bunch of problems at once. Quezon City in the Philippines, for instance, has transformed unused land into more than 300 gardens and 10 farms, in the process training more than 4,000 urban farmers. Detroit is speckled with thousands of gardens and farms. In the Big Apple, the nonprofit Project Petals is turning vacant lots in under-resourced neighborhoods into oases. “You have some places in New York City where there’s not a green space for 5 miles,” said Alicia White, executive director and founder of the group. “And we know that green spaces help to reduce stress. We know they help to combat loneliness, and we know at this point that they help to improve our respiratory and heart health.”

That makes these community spaces an especially potent climate solution, because it’s getting ever harder for people to stay healthy in cities due to the urban heat island effect, in which the built environment absorbs the sun’s energy and releases it throughout the night. Baking day after day during prolonged heat waves, the human body can’t get relief, an especially dangerous scenario for the elderly. But verdant patches reduce temperatures by releasing water vapor—essentially sweating into the neighbourhood—and provide shade. At the same time, as climate change makes rainfall more extreme, urban gardens help soak up deluges, reducing the risk of flooding. 

Oddly enough, while the oven-like effect is perilous for people, it can benefit city farms. On rooftops, scientists are finding that some crops, like leafy greens, thrive under the shade of solar panels, but others—especially warm-season crops like zucchini and watermelon—grow beautifully in harsh full-sun conditions. “Most of our high-value crops benefit from the urban heat island effect, because it extends their growing season. So growing food in the city is actually quite logical,” said horticulturist Jennifer Bousselot, who studies rooftop agrivoltaics at Colorado State University. “This summer we had cucumbers that were the size of baseball bats, that were perfectly suited to the green roof.”That’s not all that’s thriving up there. Bousselot and her team are also growing a trio of Indigenous crops: corn, beans, and squash. The beans climb the corn stalks—and microbes in their roots fix nitrogen, enriching the soil—while the squash leaves shade the soil and reduce evaporation, saving water. In addition, they’ve found that saffron—an extremely expensive and difficult-to-harvest spice—tolerates the shade of rooftop solar panels. Water leaving the soil also cools the panels, increasing their efficiency. “We’re essentially creating a microclimate, very much like a greenhouse, which is one of the most optimal conditions for most of our food crops to grow in,” Bousselot said. “But it’s not a system that needs heating or cooling or ventilation, like a greenhouse does.” That makes these community spaces an especially potent climate solution, because it’s getting ever harder for people to stay healthy in cities due to the urban heat island effect, in which the built environment absorbs the sun’s energy and releases it throughout the night. Baking day after day during prolonged heat waves, the human body can’t get relief, an especially dangerous scenario for the elderly. But verdant patches reduce temperatures by releasing water vapor — essentially sweating into the neighborhood — and provide shade. At the same time, as climate change makes rainfall more extreme, urban gardens help soak up deluges, reducing the risk of flooding. Oddly enough, while the oven-like effect is perilous for people, it can benefit city farms. On rooftops, scientists are finding that some crops, like leafy greens, thrive under the shade of solar panels, but others — especially warm-season crops like zucchini and watermelon — grow beautifully in harsh full-sun conditions. “Most of our high-value crops benefit from the urban heat island effect, because it extends their growing season. So growing food in the city is actually quite logical,” said horticulturist Jennifer Bousselot, who studies rooftop agrivoltaics at Colorado State University. “This summer we had cucumbers that were the size of baseball bats, that were perfectly suited to the green roof.

”Community gardens down on the ground in New York City, Project Petals has seen a similar bonanza. Whereas agricultural regions cultivate vast fields and orchards of monocrops, like grains or fruit trees, an urban farm can pack a bunch of different foods into a tight space. “If you could grow it in rural areas, you could grow it in the city as well,” White said. “We’ve grown squash, snap peas, lemongrass. In our gardens, I’ve seen just about everything.”

That sort of diversification means a cornucopia of nutritious foods flows into the community. (Lots of different species also provide different kinds of flowers for pollinators — and the more pollinators, the better the crops and native plants in the area can reproduce, creating a virtuous cycle.) That’s invaluable because in the United States, access to proper nutrition is extremely unequal.........In Mississippi, for example, 30 percent of people live in low-income areas with low access to good food, compared to 4 percent in New York. This leads to “silent hunger,” in which people have access to enough calories — often from ultra processed foods purchased at corner stores — but not enough nutrients.......read on.      https://grist.org/cities/how-urban-farms-can-make-cities-more-livable-and-help-feed-america/

Housing shortages in big cities are bad for Canada's productivity growth.  Ricardo Hausmann and Eric Protzer , Special to Financial Post Published Apr 02, 2026   A concise explanation by Ricardo Hausmann and Eric Protzer. Financial Post    On April 9, Ricardo Hausmann, the founder and director of Harvard’s Growth Lab, will deliver the first talk of The Canadian Standard of Living, Productivity and Innovation lectures — a series of events focused on strengthening Canada’s standard of living hosted by the Centre for International Governance Innovation and sponsored by Savvas Chamberlain. Here, he and Growth Lab senior research fellow Eric Protzer explore how Canada’s housing crisis is holding the economy back. Canada’s lacklustre productivity growth is generally presented as an economic problem and its housing crisis is usually treated as a social problem. Those things are true, but there is also a deeper connection between the two. Much of the debate over Canada’s weak economic performance asks why the country has not generated more innovation, more scale and more world-class firms. But there is another question, just as important: When positive productivity shocks do occur, why does Canada so often fail to turn them into broader national prosperity? The answer lies in the interaction between two facts. First, growth in advanced economies has become increasingly biased toward knowledge-intensive activities that prefer large cities. Second, Canada’s urban regulations make it unusually hard for those cities to grow. 

Over the past half century, cities in high-income economies have shifted away from manufacturing and toward skilled services, technology, finance, life sciences and other knowledge-intensive sectors. This is not just industrial change. It is also a geographic change.  Older sectors often needed land, proximity to raw materials or room for large physical plants. Many modern sectors depend more on dense interaction among specialists. A major hospital works because many different kinds of expertise are available in one place. The same is true of software, finance, engineering, media and biotechnology. Production increasingly depends on bringing together many heads that know different things. Large cities have an advantage because they offer deeper pools of those specialized varieties of talent. That is why growth has become more metropolitan. Canada’s population growth has become increasingly concentrated in the country’s 10 largest cities. In the 1970s and 1980s, they accounted for only a bit more than half of total population growth. In the most recent period, they absorbed more than 80 per cent. That is the spatial footprint of a changing economy. So far, this is familiar territory......modern growth likes big cities.

The deeper issue is what happens next.The key concept is spatial equilibrium. People are free to move across cities within a country. They choose among job opportunities, wages, housing costs, commute times, schools and amenities. That means what happens in one city affects the whole economy. Imagine that a city receives a positive productivity shock. Perhaps a cluster of firms becomes more innovative. Perhaps a university or hospital system reaches critical mass. At current wages, employers there want to hire more people and expand.  If housing supply is elastic, the result is straightforward. More homes get built. More workers move in. Employment rises. Output expands. Migrants gain access to better opportunities.  Workers elsewhere may also benefit as labour becomes scarcer where they live and as the booming city buys more from the rest of the country. In this world, a productivity shock in one city raises prosperity more broadly. 

But now consider the opposite case. Suppose housing supply is completely inelastic because zoning is restrictive, approvals are discretionary, minimum lot sizes and parking rules suppress density and incumbent neighbourhoods resist change. Firms in the productive city still want more workers, but workers cannot move in at scale. Instead, they bid against one another for a largely fixed stock of homes. Prices rise. Rents rise. Population growth is stunted.  But now consider the opposite case. Suppose housing supply is completely inelastic because zoning is restrictive, approvals are discretionary, minimum lot sizes and parking rules suppress density and incumbent neighbourhoods resist change. Firms in the productive city still want more workers, but workers cannot move in at scale. Instead, they bid against one another for a largely fixed stock of homes. Prices rise. Rents rise. Population growth is stunted.This is the central point often missing from Canada’s housing debate. The problem is not only that expensive housing hurts families. It is that low housing elasticity prevents the country’s most productive cities from scaling up. It blocks the mechanism through which local productivity gains spread into national income gains.

In that world, the productivity shock still exists, but it is transmitted differently. Instead of showing up mainly as more people doing more productive work, much of it is capitalized into land values. The gain is transformed into real-estate rents, not higher living standards. This is the central point often missing from Canada’s housing debate. The problem is not only that expensive housing hurts families. It is that low housing elasticity prevents the country’s most productive cities from scaling up. It blocks the mechanism through which local productivity gains spread into national income gains. Silicon Valley is the classic illustration. It enjoyed one of the most extraordinary productivity booms in modern history. Yet because housing supply was so constrained, much of that success appeared as astronomical land values, punishing commutes and exclusion rather than as the population growth that would have allowed more people to participate directly in the boom. Instead of spilling over into broad-based national growth, too much of the gain was absorbed into the price of artificially scarce urban land. This is the central point often missing from Canada’s housing debate. The problem is not only that expensive housing hurts families. It is that low housing elasticity prevents the country’s most productive cities from scaling up. It blocks the mechanism through which local productivity gains spread into national income gains.........    https://financialpost.com/news/economy/canada-housing-crisis-is-productivity-crisis

How ‘Daylighting’ Buried Waterways Is Revitalizing Cities Across America. Urban centers are exhuming creeks and streams once covered up to control floodwater—and bringing life back in the process. Smithsonian Jim Morrison - Science Correspondent March 15, 2023  For a century, Jordan Creek cut across downtown Springfield, Missouri. As in so many other 19th-century cities, the waterway was a founding centerpiece of the town. But over the decades, the creek regularly unleashed a tantrum of flooding into the city’s commercial heart. By 1927, residents had tired of rebounding from one watery attack after another. They created tall concrete banks to cage the creek. When that wasn’t enough and the area flooded again five years later, the city entombed the waterway, adding a lid and encasing it in tunnels hidden under city streets. “It was man’s attempt to confine and control this floodwater,” says Kirkland Preston, an engineer in Springfield’s Public Works Department. “That was the old way of thinking.”

For a while, that controlled the floods. But the creek festered in its concrete coffin, a stagnant dumping ground for junk that filled with polluted runoff in seconds during storms and overflowed into other streams. Eventually, the water won. It always does. The neighborhood flooded in 2000, 2008 and 2016. Property damages ranged from $1 million to $15 million. For two decades, the city discussed freeing the creek and allowing water to disperse over the floodplain. Finally, after a process that involved public input, a design phase and securing funding, a $25 million plan to uncover 1,100 feet of Jordan Creek and build three bridges is moving forward.

“The new way of thinking is to give the water some room, allocate the riparian area to floodings and just let nature be nature,” says Preston, the project manager for Renew Jordan Creek.

Exhuming buried waterways to bring them back to life is a process known as “daylighting.” Concrete culverts and other coverings are removed and an attempt is made to restore the natural flow and the surrounding ecosystem. Prodded partly by increased flooding resulting from more intense and more frequent rainstorms, cities across the country are shining the light on once-dark creeks, streams, brooks and rivers. Boston; Providence, Rhode Island; New York; Berkeley, California; Dubuque, Iowa; Norfolk, Virginia; Detroit; St. Louis; and Charlotte, North Carolina, have all either completed daylighting projects or have them in the works. The primary goal of the Springfield project is flood control. But, like other daylighting projects across the country, the work has a variety of benefits. Native plantings will help improve the water quality by filtering storm runoff. The stream will replace what has become an unsightly, graffitied landscape that is an unsafe sheltering spot for the city’s homeless. As the design report notes, the green space will become jewelry in a “string of pearls” connecting parks and green areas in the city’s “Quality of Place” initiative. “Words like ‘transformational’ get used a lot to describe the project,” Preston says, “because it is an underutilized part of downtown and it’s right near Missouri State University. It has the potential to be really impactful.”

The benefits go beyond mitigating flooding and creating soothing green spaces, too. Ann Riley, the author of Restoring Neighborhood Streams and one of the first proponents of daylighting, likes to say that “stream restoration is neighborhood restoration.” Proponents in the early days decades ago, she says, often were business owners who wanted to make urban areas attractive again. The Springfield project may spur economic development and increase property values and tax revenue, something that’s happened in other cities. Returning the Napa River as the centerpiece of Napa, California, removed a requirement for flood insurance and is credited as a catalyst for $1 billion of investment in hotels, shops, restaurants and office space. In other cities, daylighting helps relieve the pressure on overburdened stormwater and sewer systems. It diverts clean water from wastewater plants, saving cities money to pay for treatment. While the projects can be expensive, they end costly maintenance. In a few cities, cost-benefit analyses showed returning to nature was cheaper than maintaining concrete culverts. And they may right a wrong. In some cities, public housing was built atop buried rivers, causing flooding and health problems for residents. Norfolk, Virginia, tore down public housing and daylighted a creek that is the core of a park that also provides flood protection. “Daylighting reveals another layer of these hidden worlds of streams, right under our feet in the cities,” says Gary Belan, senior director of clean water supply at American Rivers, which has promoted the practice and published a white paper on it. “It’s exciting to be able to re-explore and rediscover those assets.”

Those waters initially were the heart of cities. But as cities grew, flooding became a problem. So did the lack of space. Burying streams created room for housing and industry. The combination of development and streams channeled into underground pipes became a solution that was a problem. Roads and other hard surfaces prevented water from soaking into the ground and funneled more rainwater into the enclosed streams than they could handle. That cycle repeated in city after city. Stream after stream disappeared, lurking below. Researchers at the University of Maryland reported that 66 percent of Baltimore streams are buried. One study found that Philadelphia had covered 73 percent of its streams. Detroit has lost 85 percentof its stream channels since 1902. An interactive map created by the District of Columbia shows the dramatic transformation: a squiggly maze of historical streams, and a smaller, sterile portrayal of what remains. Only 30 percent of the streams that flowed through the district at the start of the 19th century remain today. Washington, D.C. is among cities including Oakland, California; Baltimore; and Portland, Oregon, that have created buried stream maps.......read on   https://www.smithsonianmag.com/innovation/how-daylighting-buried-waterways-is-revitalizing-cities-across-america-180981793/