Transforming Soil in a City of Industry for Urban Farming: Urban Tilth

Madeline Ostrander is a Seattle-based climate journalist and the author of At Home on an Unruly Planet: Finding Refuge on a Changed Earth, one of Kirkus Review’s 100 best nonfiction books of 2022. The former Senior Editor of YES! Magazine, her writing has also appeared in The Atlantic, The, The Nation, PBS’s NOVA Next, Slate, and numerous other outlets.

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It is a radical thing to imagine you can grow food in an oil town.

The city of Richmond, California, has a long tradition of kitchen gardens, flower nurseries, and backyard farm animals. But it also grew up around industry—especially an oil refinery. Built in 1902 and now run by Chevron, the refinery is one of the largest emitters of carbon pollution on the West Coast. Such industry leaves both visible and invisible marks all over an urban landscape. Air pollution can deposit on soils, for instance. In 2012, when a major refinery fire and explosion at the Chevron Richmond facility sent a 4,000-foot-high plume of black smoke into the air—and drove about 15,000 people to nearby hospitals and doctors’ offices with respiratory complaints and headaches—flurries of ash and dark material also fell to the ground around parts of the city.

So a couple years later, when Doria Robinson—director of a small but audacious Richmond-based agriculture organization called Urban Tilth—wanted to open a new farm just a couple miles from the refinery fenceline, she knew she’d have to reckon with the possibility of soil contamination.

Soil is an ecosystem. Peer through a microscope, and soil can be a forest of half-composed stems and leaves with filigreed veins, shiny mites and little bugs, worms and their glistening trails, netted root hairs, strands and filaments of fungi, and various microbes and molds, a furious mix of rot and rebirth. Soil is also a kind of historical record—it hangs onto waste and files it into layers of accumulated dust and particles. In some kinds of soil layers, you can find the char of millennia-old fires or volcanic events. Soil can also be forgiving: in experiments, fungi and microbes have sometimes been able to munch through toxic substances and break them down, even clear away some residues of oil spills.

For a long time, Urban Tilth had relied on new soil with no memory, manufactured by nurseries, donated and hauled to its gardens. In the long run, it would be hard to grow a lot of food in Richmond if the soil always needed replacing and importing. The question remained: Could the soil endemic to Richmond ever be safe enough?

There’s never been a lot of study of what happens to plants and dirt just after industrial accidents. But there were reasons to worry. For instance, after an industrial fire at a warehouse, some British scientists had detected alarming levels of polycyclic aromatic hydrocarbons, or PAHs, carcinogens and by-products of combustion. The scientists determined that the level of PAHs was 70 times higher than normal in grass shoots and 370 times higher in soil.

Joshua (Josh) Arnold, a soil science student at the University of California, Berkeley, had just moved to Richmond at the time of the refinery fire. “I remember just being absolutely astounded that there was a refinery there! I thought I was moving to the Bay Area that’s super environmentally friendly,” he recalls. Two years later, Josh, who had just graduated, and two others, an organic gardening teacher and a Ph.D. student in soil science, offered to help other Richmonders test the soil. They recruited people from all over the city to volunteer their yards and dug samples from nineteen spots in Richmond. They sent bags of dirt away to labs, searching for trace amounts of carcinogens like xylene, benzene, and toluene, found in crude oil—and PAHs. Although these are common contaminants, it is surprisingly difficult to find any standardized safety rules specifically for residential soils. There’s no straightforward consensus about what concentration of these chemicals the average row of backyard tomatoes or roses can hold or what might still be safe if, say, a child eats some dirt or a dog tracks garden mud through the living room. So the students cobbled together a list of health guidelines from a motley range of sources. When the results came back, they found few things of great concern—traces of hydrocarbons and xylene. The students recommended earthworms and compost as an antidote to any lingering contamination. And at the middle school farm, the Urban Tilthers aggressively layered on compost and cover crops and followed the guidelines offered by the soil science students until Doria felt safe to let teens plant vegetables there again.

This act of soil renewal prepared Urban Tilth for a far more ambitious project to reclaim abandoned land at the edge of the city.

Richmond sits at the northwest tip of Contra Costa County, which curves east along the Suisun Bay and south, behind Oakland and Berkeley—a mishmash of agriculture and industry. To the north lies a community outside city limits called North Richmond. It is somewhere between urban and rural, like a place that has fallen off the map. The community of about 4,000 remained “underserved”—with not a lot of help from government entities. Garbage dumps and recycling centers, storage lots, homeless encampments, and run-down convenience stores were splotched through the area, along with an elementary school and residential houses that were too often aging and cramped.

The area was also riddled with vacant lots, and the supervisor of Contra Costa County had recently become an enthusiast of urban farming. He asked his staff to sniff out some property that might still be suitable for growing food, then chose Urban Tilth to develop a three-acre plot of land between two creeks. The property, three miles north of the refinery, was tiny compared to an industrial farm, but it would be large enough to demonstrate what was possible and to allow people’s imaginations to unfurl.

The chosen land parcel spread northeast from an intersection of Fred Jackson Way (named after a local civil rights activist). It lay in a historic Japanese flower-growing district; some descendants of those growers still owned the property next door and rented greenhouses to an orchid cultivator and a wholesale seedling nursery. Numerous Indigenous Huchiun Ohlone villages had stood near and around the land long before North Richmond was settled by migrants from elsewhere. A local association of Black cowboys had run horses there. But industry had never touched it, and the first soil tests came back clean.

It took two years for the Tilthers to negotiate with the county—to rezone the land, get permits, and draw up a lease.

When Doria first laid eyes on the place, it was a jungle of weeds higher than her head, in some spots twice as high, with a few trees scattered within them, and some weeping willows slumped by the street like long-haired old men. Urban Tilth mowed the weeds down. But by the time the lease was approved, they had grown back, especially the blackberries.

Much of the coastal West suffers from an infestation of an especially aggressive variety of blackberry from Eurasia. (It’s rumored that the famed botanist Luther Burbank first planted them on American soil, and from there, the thorny fruits went rogue.) While the berries are tasty, the canes sometimes grow into a colossal tangle—a Medusa with barbed tentacles sharp as knives, capable of grabbing and shredding clothing and skin.

The thicket of thorns at the farm site was roughly the size of eight basketball courts lined end to end, surrounded by other dense weeds, including enormous, fragrant, stubborn-rooted fennel. The land hadn’t been fenced for four decades, and as the Tilthers explored further, they discovered it had also been an informal dump and was piled with hidden trash.

Yet Doria’s optimism was unscathed. She could see it already, a vision in the weeds—the rows of vegetables, an educational center. “My eyes are permanently rose covered,” she says. “I’m like, ‘Oh, man, this is the best farm ever.’” By the time they began clearing the land, she and a colleague, Tania Pulido, had already assembled a group of local residents to help them in this seemingly quixotic process—and their dream for the site grew more elaborate—a farm stand, an amphitheater, perhaps even a café. “We just had no idea what the heck we were jumping into,” Tania said afterward.

The land itself was cantankerous. First, the Tilthers rented a team of goats to chomp down the weeds. But the goats “looked at that blackberry patch, and they’re like, ‘Oh, no. You will have to deal with that,’” Doria said. Then they brought in large mechanized equipment—toothy mowers and mulchers, grinders and bulldozers. Underneath the weeds, they found orphaned couches, chimneys, chunks of broken asphalt, used motor oil, several discarded wallets including credit cards, rusty barbed wire, old tires. Urban Tilth hired workers from several local organizations, including a program that worked with women who were recently released from prison and eager to gain new skills. With hands and machines, these crews dragged dozens of semitrailer truckloads from the site.

But the land was like a geologic formation of waste, strata full of trash layered like fossils in rock. “We went through a process of realizing that everything we were standing on was also dumped material, “Doria remembered. With the machines, they scraped the ground surface, then walked behind and scooped up more debris by hand. “We would literally just clear a few feet at a time, trying to get all the stuff out.”

The Berkeley soil science students came to the farm to run a more detailed search for contamination. They drew a grid over the entire lot; then Urban Tilth’s summer apprentices retrieved soil samples from each square of the grid. The soil was so hard that the kids had to use pickaxes in some places to extract the earth. The results came back from two different labs: there were dregs and residues of asphalt and one spot of lead, all in small amounts. The ground was also nearly devoid of life or nutrients—it was mostly crushed rock and clay. But the situation could be handled as before—with compost and earthworms and bugs.

“We need to put back a ton of organic materials,” Doria said. We just need all kinds of rot to be happening throughout the site. Truckloads of manure arrived on the land, forty cubic yards of compost every week, donated by the same company that was contracted to handle city organic waste, along with straw—spread and raked and spread again. Over and over for months, dumping manure, turning manure, planting cover crops of buckwheat and daikon radish. Turning the soil again. Rot and renewal. In the fall of 2016, while this process was still underway, Doria and the Tilthers decided to plant what they could. At first, they had to bring in soil and more compost to create a series of mounded rows, arranged in a circle, where they grew mustard greens, collard greens, garlic, Swiss chard, cabbage, broccoli, and cilantro.

The next year they plotted an orchard on the northwest edge and sectioned it off, ten-foot-by-ten-foot squares, each a home for a tree. About 350 volunteers showed up and laid down more layers of manure, straw, and compost. And in each square, they placed a bare-root whip, a little stick that would become an apricot, peach, persimmon, pear, or apple tree. Over the next year, the vast majority of the trees survived. Within a couple years, they were bearing fruit that was sent to members of Urban Tilth’s farm share program.

About a year later, the Tilthers could finally begin planting in crop rows, in soil they were building there on the farm.

The first greenhouses went up.

It was the un-wasting of land, the reimagining of place.

It was also an act of rebellion. No one would tell Urban Tilth what was and was not possible on an old, broken bit of ground.

Excerpted from At Home on an Unruly Planet: Finding Refuge on a Changed Earth by Madeline Ostrander. Published by Henry Holt and Company. Copyright © 2022 by Madeline Ostrander. All rights reserved.

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