Less than a five minute walk outside his office on the University of California Berkeley campus, Thomas Carlson excitedly points to a towering wild fennel plant and strides towards it with a dozen eager students in tow. The plant’s leaves have grown tough, but he encourages the students to sample its seeds, which are vaguely sweet and taste of anise. For a few minutes, the group tentatively chomps down as he details the plant’s medicinal and nutritional benefits before moving on in search of the next discovery.

Carlson, an ethnobotantist in UC Berkeley’s Department of Integrative Biology, is one of three researchers funded by the Berkeley Food Institute to study the prevalence, nutritional value, and potential toxicity of wild foods—AKA weeds—commonly found in urban neighborhoods in the East Bay. Their thinking is, people who lack access to healthy foods rarely get enough micronutrients and fiber. Could wild edibles, which are sustainable and potentially abundant, be a reliable source of fresh, free, and nutritious food?

The inspiration for the study, entitled “Reaping Without Sowing: Urban Foraging, Sustainability, Nutrition, and Social Welfare,” sprung from co-researcher Philip Stark’s observation that wild edibles thrive where people don’t weed—meaning low-income areas often have more to eat than high-income areas. Stark, who is the chair of UC Berkeley’s statistics department, is also a longtime, ardent urban forager.

What started as a few innocent handfuls of miner’s lettuce eventually led to a full-blown obsession. Using two field guides on his phone in addition to Samuel Thayer’s Nature’s Garden at home, Stark began identifying new plants each week—and taking them home for dinner. These days, he no longer buys greens.

“It doesn’t take long for these plants to become your old friends,” Stark says. “Botanical rubbernecking has taken over my life.”

Foraging for wild edibles has grown increasingly popular over the past few years. Educational tours are widespread. The menu at Copenhagen’s Noma, considered one of the world’s best restaurants, features almost exclusively foraged foods. Two and a half miles from downtown Seattle, urban farmers and foragers are in the process of developing a seven-acre food forest meant in part to encourage foraging. However, foraging is still associated more with parks and open land, than with bustling cities. Carlson and Stark are not aware of any other systematic studies of the availability of wild foods in urban areas.

The two scientists have begun taking inventory of wild foods growing in parts of Berkeley, Oakland, and Richmond where fresh food is scarce. So far, they’ve been surprised at the abundance of what they’ve found.

Nearing the end of summer and in a record drought, the team found ample plantago, mallow, dandelion, fennel, and dock. “I knew that even in the driest part of the year, there would still be some edibles available, but I was surprised by how much,” says Carlson. “We’re worried about where water is going to come from, and these plants are still plentiful.”

In addition to mapping the species occupancy of each neighborhood themselves, Carlson and Stark are encouraging their students to use the mobile app iNaturalist to crowd-source the data collection over the course of the next year. A record of what and how much they’ve found thus far can be found at forage.berkeley.edu. Samples of the plants will also be dried and deposited into the university’s herbarium collection.

Carlson and Stark have also begun testing soil samples for contaminants. So far, none of the toxins they’ve tested for have come close to surpassing acceptable threshold levels, with the exception of lead. But Stark says, “We think that the plants growing in even the worst soil we have found are in fact safe — but we’re going to check.”

Herbicides aren’t much of an issue either. As Stark put it: “Have you ever tried to eradicate dandelion from your yard? Good luck, unless you plan on using chemical weapons.” In other words, if herbicides were present, the wild edibles they’re finding probably wouldn’t be there. On the other hand, pesticides may prove to be a concern: On a recent mapping foray into West Oakland, they observed someone spraying for ants nearby.

Although both researchers are familiar with anecdotal evidence claiming wild edibles are more nutrient rich, they’re not yet willing to make that claim themselves. They won’t begin testing samples for their nutrient value until next spring, when the plants are more abundant.

Stark and Carlson are quick to acknowledge that their research has really just begun. Beyond simply categorizing and quantifying wild edibles found in urban areas, they want to determine what the barriers might be keeping people from eating more wild foods. They point to the adoption of wild foods in high-end restaurants might indicate a larger cultural shift. On that note, Stark offers up the replacement term “volunteers.”

Their enthusiasm is contagious. When I ask Stark if he truly enjoys eating his forages salads he is emphatic: “It tastes really good! Here’s what the world is offering me today. How do I balance these ingredients? How am I going to use these things in the way that’s going to be the tastiest?”

Foraging, he says, turns the world into a farmers’ market.