Growers here on the Baja Peninsula, the epicentre of Mexico’s thriving new organic export sector, describe their toil amid the cactuses as “planting the beach.”  

Del Cabo Cooperative, a supplier here for Trader Joe’s and Fairway, is sending more than 7 1/2 tons of tomatoes and basil every day to the United States by truck and plane to sate the US demand for organic produce year-round.  

But even as more Americans buy foods with the organic label, the products are increasingly removed from the traditional organic ideal: produce that is not only free of chemicals and pesticides but also grown locally on small farms in a way that protects the environment.  

The explosive growth in the commercial cultivation of organic tomatoes here, for example, is putting stress on the water table. In some areas, wells have run dry, meaning that small subsistence farmers cannot grow crops. And the organic tomatoes end up in an energy-intensive global distribution chain that takes them as far as New York and Dubai, United Arab Emirates, producing significant emissions that contribute to global warming.  

From winter until spring, farms from Mexico to Chile to Argentina that grow organic food for the US market are enjoying their busiest season.  

“People are now buying from a global commodity market, and they have to be sceptical even when the label says ‘organic’ – that doesn’t tell people all they need to know,” said Frederick L. Kirschenmann, a distinguished fellow at the Leopold Center for Sustainable Agriculture at Iowa State University. He said that some large farms that have qualified as organic employed environmentally damaging practices, like planting only one crop, which is bad for soil health, or overtaxing local freshwater supplies.  

Many growers and even environmental groups in Mexico defend the export-driven organic farming, even as they acknowledge that more than a third of the aquifers in southern Baja are categorized as overexploited by the Mexican water authority. With sophisticated irrigation systems and shade houses, they say, farmers are becoming more skilled at conserving water. They are focusing new farms in “microclimates” near underexploited aquifers, such as in the shadow of a mountain, said Fernando Frias, a water specialist with the environmental group Pronatura Noroeste.  

They also point out that the organic business has transformed what was once a poor area of subsistence farms and where even the low-paying jobs in the tourist hotels and restaurants in nearby Cabo San Lucas have become scarcer during the recession.  

To carry the Agriculture Department’s organic label on their produce, farms in the US and abroad must comply with a long list of standards that prohibit the use of synthetic fertilizers, hormones and pesticides, for example. But the checklist makes few specific demands for what would broadly be called environmental sustainability, even though the 1990 law that created the standards was intended to promote ecological balance and biodiversity as well as soil and water health.  

Experts agree that in general organic farms tend to be less damaging to the environment than conventional farms. In the past, however, “organic agriculture used to be sustainable agriculture, but now that is not always the case,” said Michael Bomford, a scientist at Kentucky State University who specializes in sustainable agriculture. He added that intense organic agriculture had also put stress on aquifers in California.  

Some organic standard setters are beginning to refine their criteria so that organic products better match their natural ideals. Krav, a major Swedish organic certification program, allows produce grown in greenhouses to carry its “organic” label only if the buildings use at least 80 percent renewable fuel, for example. And in 2010 the Agriculture Department’s National Organic Standards Board revised its rules to require that for an “organic milk” label, cows had to be at least partly fed by grazing in open pastures rather than standing full time in feedlots.  

But each decision to narrow the definition of “organic” involves an inevitable tug-of-war among farmers, food producers, supermarkets and environmentalists. While the U.S. regulations for organic certification require that growers use practices that protect water resources, it is hard to define a specific sustainable level of water use for a single farm, “because aquifer depletion is the result of many farmers’ over utilizing the resource,” said Miles McEvoy, head of the National Organic Program at the Agriculture Department.  

While the original organic ideal was to eat only local, seasonal produce, shoppers who buy their organics at supermarkets, from Whole Foods to Wal-Mart, expect to find tomatoes in December and are very sensitive to price. Both factors stoke the demand for imports. Few areas in the US can farm organic produce in the winter without resorting to energy-guzzling hothouses. In addition, US labour costs are high. Day labourers who come to pick tomatoes in this part of Baja make about US$10 a day, nearly twice the local minimum wage. Tomato pickers in Florida may earn US$80 a day in high season.  

Manuel Verdugo, 42, began organic tomato farming on desert land in San Jose del Cabo five years ago and now owns 12.1 hectares in several locations. Each week he sends 2 1/2 tons of cherry, plum and beefsteak tomatoes to the US under the brand name Tiky Cabo.  

He has invested in irrigation systems that drip water directly onto plants’ roots rather than channelling it through open canals. He is building large shade houses that cover his crops to keep out pests and minimize evaporation. Even so, he cannot farm four hectares in the nearby hamlet of La Cuenca, because the wells there are dry.  

At another 5-year-old organic farm, Rosario Castillo says he can cultivate only roughly 7 1/2 hectares of the 40 he has earmarked for organic production, though he dug a well several months ago to gain better access to the aquifer. The authorities ration pumping and have not granted him permission to clear native cactuses.  

“We have very little water here, and you have to go through a lot of bureaucracy to get it,” Castillo said.  

Many growers blame tourist development – hotels and golf courses – for the water scarcity, and this has been a major problem in coastal areas. But farming can also be a significant drain. According to one study in an area of northern Baja called Ojos Negros, a boom in the planting of green onions for export a decade ago lowered the water table by about 40 centimetres a year.  

“They were pumping a lot of groundwater, and that was making some people rich on both sides of the border at the expense of the environment,” said Victor Miguel Ponce, a professor of hydrology at San Diego State University.  

The logistics of getting water and transporting large volumes of perishable produce favours bigger producers. Some of the largest are U.S.-owned, like Sueno Tropical, a vast farm with rows of shade houses lined up in the desert that caters exclusively to the U.S. market.  

While traditional organic farmers saw a blemish or odd shape simply as nature’s variations, workers at Sueno Tropical are instructed to cull tomatoes that do not meet the uniform shape, size and cosmetic requirement of clients like Whole Foods. Those “seconds” are sold locally.