For years, Leslie Leavens watched as the work crews in her Ventura County lemon orchard steadily shrank, leaving an untold number of fruit unharvested and rotting in the sun.

"We used to have regular crews of 30 folks. Then it dwindled to 25 and 20, and in some cases, the crew sizes have been reduced to 15," she said.

Eventually, there weren't enough people to pick all the lemons at harvest.

"We lost hundreds of thousands of dollars of lemons to the ground because we did not have the labor to harvest it," she said.

Lemon picking is back-breaking work. Harvesting requires the precision of human hands, since the fruit can only be picked at a certain size and color, and the stem must be cut just so.

"It's not something people are willing to do, generally speaking, certainly not domestic workers,” she said.

This shrinking workforce is not unique to Leavens or her lemons. California farmers have been grappling with a labor shortage since about 2006, said Bryan Little, director of labor affairs for the California Farm Bureau.

Among the reasons: a stronger economy and lower birth rate in Mexico. Some California growers have sold their land and moved their farming to Mexico. And, more recently, under the Trump Administration, fewer people are crossing the border, Leavens explained.

"There is great fear as far as crossing the border. It's very expensive, and let’s face it, the harvesters for the agriculture industry, many of them, probably 70 percent at least, are undocumented. It's very difficult for them, particularly now. There is greater fear for them," she said.

The peak of the major harvest of the year is July and August, but already growers are ramping up their workforces, according to John Krist, who heads the Ventura County Farm Bureau, an advocacy organization for local growers.

Krist said some growers have taken what he calls the "extraordinary step" of using the federal H-2A visa program to secure legal guest workers.

While popular in Georgia and North Carolina agriculture, the guest worker program is used far less in California – only about 18,000 of the state's 400,000 farm workers are on H2-A visas, Little said.

Farmers don't like the red tape of the program and the high costs that come with employing guest workers, Krist said, explaining that employers are required to provide the workers with free housing.

"It’s a sign of how desperate our growers are that in one of the most expensive housing markets in America, they are willing to pony up what it takes to secure housing for these people," he said.

But Ventura County's labor needs are also especially great. The area's top crops are strawberries, lemons and avocados, which are delicate and cannot yet be harvested with machines.

"On a 'per acre basis,' it's the super labor-intensive stuff that we do down here on the coast," he said. "That makes us disproportionately vulnerable to these changes in the labor force."

This harvest season, Leavens will house 50 guest workers in apartments. Her Monterey County orchards will put up a few more dozen workers in hotels, and provide them meals and transportation.

The housing will run into the hundreds of thousands of dollars, she said, but she will recoup those costs by getting a complete lemon harvest.

"We’re embracing it out of desperation, but it's also turning out to have benefits that we didn’t realize that it would have," she said, noting the quality of the work is better. "It's a real benefit to the workers as well. They aren’t in fear, they have a contracted period of time, and they can go back home at the end of the season."

Krist said so far the larger-scale farmers are trying the program; they have the means to provide the housing. However, he anticipates that as smaller-scale farmers hear positive reviews, they'll try it, too.

"The advantages are, you’ve got the number of people you want. You know exactly when they’re going to be there. You’re sure they’re going to show up. And they work with you for the season, so you’ve got the labor you need to get the job done," he said.