Long-time strawberry farmer Rod Koda has rows of plants on his California farm that are still producing fruit well after the harvest would typically end.

The fields brimming with green near the Pacific Coast have produced nearly twice the amount of organic strawberries this year as other plots thanks to steam, he said. The bountiful plots were treated with steam before Koda planted his organic strawberries as part of a project aimed at finding an alternative to chemical fumigants used to kill soil-borne diseases and weeds.

“It’s a very noticeable difference,” Koda said.

Steam has been used for decades in greenhouses, and researchers in California have been working to adapt the technology to the fields where strawberries, one of the state’s key crops, are grown near the Pacific Coast. It’s part of a broader push to help organic farmers become more productive and reduce the use of chemicals that environmental advocates say pose a health risk to farmworkers and those who live near the fields.