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Nighttime Harvests Can Protect Farmworkers from Blistering Heat, but They Bring New Risks

Workers have taken to nocturnal harvesting schedules to avoid soaring daytime temperatures. Experts say more data, and more protections, are necessary.

A black-and-white photo shot in the dead of night shows farm workers harvesting grapes under bright flood lights.
Workers harvest grapes at nighttime to avoid sweltering heat during the day.
Stolpman Vineyards

This article was produced in partnership with Nexus Media News. Twilight Greenaway contributed reporting.


In the summer months, Flor Sanchez and the members of her harvest crew rise before dawn and arrive at a cherry orchard in Washington state’s Yakima Valley when there is only the slightest hint of daylight.

“We use headlamps,” she says, to carry ladders to the trees. Climbing up into the branches to harvest the ripe fruit in near-darkness, she says, “seems a little dangerous.” Headlamps cast shadows that can make it difficult to see the fruit. Setting up ladders in the dark also poses a danger.

Elizabeth Strater, director of strategic campaigns with United Farm Workers, says for field crops like onions and garlic, harvesting at night by headlamp or flood lights poses less risk than picking tree fruit because ladders aren’t needed, the short plants don’t create shadows, and workers know exactly what to pick even if they can’t completely see what they’re doing. The produce itself is also more durable. Winegrape harvest also often takes place at night.

Across super-hot regions, nocturnal harvest, as Strater calls the practice, has become increasingly common. As climate change pushes summer temperatures higher on more consecutive days, and scientists are forecasting even warmer years ahead, more workers may find themselves in the field at night and in the early morning hours. And while some safety measures have been put in place, more data is needed to assess the challenges workers face.

Sanchez says she has only worked an overnight harvest shift once. “It’s complicated and dangerous,” she says, though she knows others are working them more often.

Jon DeVaney, president of the Washington State Tree Fruit Association, says overnight shifts are disruptive and generally undesirable.

“We’ve had a number of orchardists offer nighttime work — it’s usually as an offer more than a demand,” he says, because when cherries are ready and need to be harvested, cooler temperatures overnight reduce the risk that the skin will tear. High heat during the day softens the fruit and makes this type of damage more likely, he says. DeVaney says, in general, workers are less productive during overnight shifts because they’re tired and it’s harder to do the job. Scheduling surprises also interrupt home life. But overnight temperatures can be more comfortable, and they generally stay below the threshold that triggers additional precautions for outdoor workers facing heat-related stress and illness, which can be appealing to some workers and employers alike.

At Stolpman Vineyards in the Ballard Canyon area of Santa Barbara County, California, a nocturnal harvest has long been the norm. Pete Stolpman, who runs the operation, says it’s been more than 20 years that the three-month harvest from mid-August to mid-November has been conducted entirely overnight.

“It’s for the quality of fruit,” he says. When the temperature can drop as much as 40 degrees from the daytime high, the fruit itself cools, and he says that makes for a better-quality grape — and, ultimately, wine. But beginning with his father before him, he says equal attention has been paid to employing people in a consistent, year-round way that gives them a career, not just a seasonal job.

Stolpman Vineyards

What’s critical to making it all work, he adds, is lights. “We’ve fabricated light poles on all of our fruit trailers and tractors that can illuminate four rows of vines each,” he says, “and then every crew member wears a headlamp.”

While night workers are entitled to all the same rest, bathrooms, and water breaks as day workers, Stolpman says the overnight work can offer a reprieve from the extreme heat of the summer. Before harvest, he says the workday typically starts at dawn and wraps up just as the temperatures reach uncomfortable highs. When it’s time for harvest, “it’s a welcome shift for the entire crew to be able to work in the cool of the night.”

New Regulations, Sparse Data

Washington, Oregon, California, and Colorado currently have regulations to protect agricultural workers during extreme heat. Maryland and Nevada are working on rules of their own. (The consulting firm Venable has published an overview of state rules, which include variations from indoor-only regulations for high temperatures to outdoor rules that exclude farmworkers.) The federal Occupational Safety and Health Administration is in the throes of establishing a rule that would apply nationally.

But night and early morning work poses another set of challenges. In 2020, according to data from the Bureau of Labor Statistics, 1,350 people suffered non-fatal injuries between the hours of 8pm and 8am.

According to a 2019 fact sheet from The UC Davis Western Center on Agriculture Health and Safety, “The general, unofficial consensus among a number of professionals involved in agriculture is that night work is increasing.” Yet there has been very little data collected about how the shift in timing to avoid heat might be impacting workers.

“What concerns me most is the negative impacts on workers [from] all of the adaptations that happen to their schedule, because those changes aren’t always made with their overall well-being in mind,” says Heather Riden, program director at the UC Davis center. “What does it mean to have a person work three or four hours in the morning, then come back in the evening to work another three or four hours? And what does that do for their sleep schedule, their family life, and their ability to stay awake when they’re driving at two in the morning? That is where we don’t have data; we don’t know the bigger-picture implications.”

There is research that links a long-term shift to night work in other fields to increased risks to heart disease and diet-related illnesses, but it’s not yet clear what how it will impact seasonal farmworkers.

In 2020, California approved a set of safety standards for outdoor agricultural work taking place at night that includes adequate lighting that minimizes glare, rear lighting for self-propelled equipment, pre-shift safety meetings, and reflective safety gear for workers.

Riden adds that while employers are required to adhere to the standards, she doesn’t know “whether or not CalOSHA [California Division of Occupational Safety and Health] has been doing investigations or enforcement around that.”

“Lighting is critical for safety when you’re talking about farm work,” she says. “If you think about the kinds of human interactions and safety factors that come into play when people are out in a large field in secluded areas — all of the same concerns that exist during the day exist at night, but there’s less visibility.”

For women, night work might pose additional dangers. Researchers have found that “gender-based violence against female workers is frighteningly common on U.S. farms.” One study from 2010 found that 80 percent of Mexican and Mexican American women farmworkers in the U.S. have experienced some form of sexual harassment at work.

When asked about whether sexual harassment in the field might be a concern as more workers go into the fields under the cover of darkness, Riden said, “There have been many reports that have illuminated the horrible experiences of many women farmworkers in the daylight and I would imagine that darkness raises that risk. These are the things that we need to think about as the unintended consequences of trying to solve one problem, like heat, [while introducing] another problem. And it is why illumination standards are critical.”

The Logistics Challenges of Night Harvests

In addition to the danger, the schedule disruptions and the lower productivity, overnight work exacerbates one of the big challenges farmworkers contend with: childcare.

DeVaney says for all working parents — anywhere, in any type of employment — childcare has long been an issue. That’s even more true for farmworkers, who often earn little, live in rural areas and already have irregular schedules. Early mornings and overnight shifts magnify the situation. DeVaney says workers and employers must abide by the strict rules about who can be in the fields — children cannot tag along while their parents work.

Alberta Rojas, another worker from Sunnyside, Washington, says her children are now old enough to be left at home when she has to work before dawn. But she worries about other parents. “I’ve heard conversations about many workers who have to get their kids up so early, maybe at 2:00 in the morning,” she says, “to take them to a babysitter or someone who can care for them.”

At the vineyard, Stolpman says any crew members who aren’t able to commit to the overnight shift will work during the day, sorting grapes instead. He says most often it’s the women who have conflicts with the overnight work, but sometimes there are men who need the day shift.

Strater says with onions and garlic, which are grown in places where extreme heat is common and expected, crews often know ahead of time when they will need to work overnight. They have enough advanced notice to (re)arrange childcare. But when harvest needs can change on a day-by-day basis and temperatures are irregular, some families find themselves in impossible situations, such as leaving sleeping kids in the car at the farm. Too often, Strater says, young children are left home alone.

“Every couple of years there’ll be a real terrible tragedy where kids were left home and there’s a fire,” she says. Children should never be left alone, she adds, and farmworker families can be especially vulnerable. “They’re often in cramped, substandard housing, rural areas with not a lot of infrastructure.”

UC Davis’s Riden added that the tendency for farmworkers to live in non-airconditioned homes can add to the problem. “Heat illness is a serious concern [...] particularly for folks who don’t have an ability to cool down when they go inside. As we might consider shifting when and how they work, we have to remember what they’re doing in the off time — and what their options are, because it dramatically changes their risk profile for the next day that they are at work. And if they haven’t had a proper rest time, at night or the day prior, their risk profile continues to increase at work the next day; the risk builds.”

Amy Mayer is a multimedia journalist whose audio work has aired nationally on NPR. Her written work has appeared has appeared in Boston Globe, The New York Times, Real Simple, BioScience, and Newsweek.