California strawberry farmer Rod Koda has found that using steam technology to treat his fields before planting organic strawberries has led to noticeably higher yields and healthier crops on his coastal farm. Koda’s steam-treated plots have produced nearly double the organic strawberry output compared to untreated areas, with fruit still ripening beyond the usual harvest season.

The use of steam to sterilize soil is not new, having been employed in greenhouses for many years, but researchers in California have been adapting the method for open-field use where strawberries are cultivated. This effort is part of a broader initiative to provide organic farmers with viable alternatives to chemical fumigants, which are traditionally used to control soil-borne diseases and weeds but have raised health and environmental concerns.

Rick Tomlinson, president of the California Strawberry Commission, said the industry has been exploring steam technology for more than a decade. Research continues to focus on increasing the speed and efficiency of steam application to make the process more practical for large-scale fields. Alongside steam, growers are testing other non-chemical soil treatments, such as oxygen deprivation techniques and breeding disease-resistant plant varieties.

Strawberries are particularly vulnerable to soil diseases due to their proximity to the ground and delicate nature, leading many growers to rely heavily on chemical fumigants. Tomlinson emphasized the economic risks growers face without effective soil disease control, noting that a severe outbreak can devastate entire strawberry fields. Currently, California produces about 90% of the strawberries grown in the United States, with strawberry cultivation occupying roughly 35,000 acres, ranking it among the state's top commodities.

University of California, Santa Cruz researcher Jenny Broome, who is involved in the steam project, reported that trials last fall included four farms, with Koda’s showing significantly better outcomes. The steam treatment not only boosted berry production but also reduced instances of fusarium wilt, a common fungal disease. Broome suggested that the technology could also benefit other crops such as lettuce and carrots, which are similarly affected by soil pathogens.

One of the main challenges remains the cost and speed of steam treatment equipment. Researchers and industry stakeholders are working to enhance machine efficiency so that larger field areas can be treated in shorter time frames.

Environmental advocates have welcomed the development of alternatives to chemical fumigants. David Andrews, chief science officer at the Environmental Working Group, highlighted that farmworkers and their families are especially vulnerable to exposure from traditional fumigants. He acknowledged that as the technology advances, the economic incentives for adopting steam treatments are becoming more favorable.

“We’re going back to the future,” Broome said, “looking at an older technology and finding new ways to engineer it for modern agricultural needs.”