Some of the efforts to produce the sought-after fuel call for growing hearty crops such as canola on unproductive land that can't support higher-value produce.
Other farmers are eyeing oilseed plants as a cover crop that might improve soil quality between more profitable plantings of berries or leafy greens.
Researchers have even started experimenting with varieties of algae that can be farmed in ponds and converted into biodiesel.
"We have one of the world's most fertile and productive growing regions," said Salinas Mayor Dennis Donohue, a radicchio farmer. "It doesn't make any sense that we shouldn't be involved in the future that's shaping up."
The trials are being conducted as high gas prices and stringent environmental regulations drive the market for alternative energy sources such as biodiesel. Derived from vegetable oils and other sources, the fuel is used to run diesel engines that have undergone slight modifications.
Transit agencies in several cities - including Houston and Columbus, Ohio - run biodiesel bus fleets. The University of California system is converting its campus fleets to run on 100-percent biodiesel. And Disneyland uses biodiesel to fuel the trains that circle the popular theme park.
Nationwide, biodiesel production has tripled in each of the past two years to reach nearly 250 million gallons in 2006, National Biodiesel Board spokeswoman Amber Pearson said.
It's not yet clear, though, that growing canola or other oilseed crops would make economic sense for California, which produces some of the nation's most valuable vegetables.
Many farmers are watching a University of California research program that has planted acres of canola in small plots throughout the state to see where it fares best.
"Our goal is to be able to provide a type of crop that will be economically feasible and return a profit back to the producer, as well as be a crop that might be able to meet industry bioenergy needs," said Rick Bottoms, who is tending an acre of canola in the Imperial Valley as part of the program.
Some observers point out that land and labor are much cheaper in Midwestern states, where such commodity crops are generally produced.
A typical biodiesel crop could earn California growers a maximum of $200 an acre each year - far less than their current average annual yield of $2,000 an acre, said Robert Van Buskirk, a scientist with the U.S. Department of Energy.
"There's a lot of research that needs to be brought to bear to incorporate these oilseed crops," said Steve Shaffer, environmental stewardship chief for the California Food and Agriculture Department.
Biodiesel producers would also be competing for market share and investment and research money with other biofuels such as ethanol.
Some 620,000 acres of corn are expected to be planted in California this year, much of which could be used to produce ethanol. In addition, new research suggests that the 40,000 acres of sugar beets grown in the state could be turned into that fuel.
Still, many farmers see opportunity in biodiesel crops, even if the yield is only enough to power their own equipment or supply fuel to nearby filling stations.
In the San Joaquin Valley, grower John Diener has planted canola on land that can't support other crops because of high salt content.
He has the canola oil converted into biodiesel that he uses to run his tractors and other farm equipment.
He uses the remaining byproducts for a salt-enriched canola meal sold as cattle feed.
Along the Central Coast, meanwhile, some farmers have been testing oilseed plants as offseason cover crops to improve the quality of soil, Donohue said.
Grower Kenneth Kimes is experimenting with a mustard seed variety developed at the University of Idaho that works as an organic fertilizer after its oils are extracted for biodiesel.