California Farmer Nearly Doubled His Strawberry Yield By Replacing Toxic Chemicals With Steam
Rod Koda has grown strawberries on his farm near Watsonville, California, for years, and his plots treated with steam before planting produced nearly twice the amount of organic strawberries this season as his other fields, with the plants still bearing fruit well after harvest would typically end. The difference was immediately visible, he told the Associated Press: the steam-treated rows were fuller, the fruit more abundant, and the plants significantly less damaged by fusarium wilt, a fungal disease that can wipe out an entire field in a bad year. The steam is injected into the soil before planting by a specialized machine, killing soil-borne diseases and weeds at the root without leaving chemical residues that persist in the soil and surrounding environment. Koda's fields are part of a trial run by Jenny Broome, a researcher at the University of California Santa Cruz, who has been working with the California Strawberry Commission and agriculture startup High Degree to adapt steam sterilization technology from greenhouse use to open field conditions. Four growers in California participated in the trials, and the steam-treated plots outperformed the others consistently. California grows 88 percent of all strawberries produced in the United States, making it by far the most consequential testing ground for any new approach to strawberry farming.
The reason steam is getting serious attention now is that the chemical fumigants strawberry growers have relied on for decades are facing increasing restrictions. Methyl bromide, long the industry standard, was phased out under the Montreal Protocol due to its impact on the ozone layer. Its replacements, including 1,3-dichloropropene and chloropicrin, are under growing regulatory pressure in California due to documented health risks to farmworkers and communities near treated fields. The strawberry is unusually vulnerable to soil diseases because it grows close to the ground, is soft-fleshed, and is planted in the same fields year after year, creating conditions where soil pathogens build up quickly if not controlled. Rick Tomlinson, president of the California Strawberry Commission, said researchers have been working on steam as an alternative for more than a decade, but the technology has historically been too expensive and slow to scale from greenhouse settings to the large open fields where California strawberries are grown commercially. High Degree's machine design, which injects steam directly into the soil at walking pace, is the development that has made field trials viable. Koda described the result on his farm simply: it is a very noticeable difference. The industry is watching his fields closely.
