U.S. lettuce growers are excited yet apprehensive about crop production-changing technology now available which will likely revolutionize the vegetable industry.

The lettuce industry has its sharply-focused eyes on the first generation of commercially available automated lettuce thinning machines now thinning green lettuces in California and Arizona.

About 99 percent of the U.S. lettuce crop is grown in the two-state area.

The thinners are designed to replace the labor-intensive hand thinning process in the $3 billion lettuce industry. About a dozen thinning machines are currently thinning lettuce beds in the West.

“The automated thinner represents a total leap forward in a crop which has been highly dependent on hand labor and allowing the machine to do the work,” says Richard Smith, University of California Cooperative Extension (UCCE) vegetable farm advisor in Monterey County.

Smith added, “The mechanical lettuce thinner (overall) does a good job. It is changing people’s thoughts on how to grow a lettuce crop.”

The thinners offer a bright ray of hope to lettuce growers who face ever worsening shortages of farm workers. In the future, automated thinners could reduce production costs, boost profitability, and reduce the industry’s reliance on a smaller, aging work force.

Current thinners on the market can handle a mix of bed widths and seed line numbers. The price of the machines can range from $70,000 to $200,000 or more, depending on the options and whether the machine is self propelled or pulled behind a tractor with a three-point hitch.

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Most automated lettuce thinners utilize ‘machine vision’ technology which integrates high-end computers, sophisticated software, and cameras to recognize which plants should be kept or terminated.

Once identified, an ingredient is sprayed or dribbled on unwanted plants.

Why is thinning necessary? During lettuce planting, extra seeds are planted in the bed to create a good plant stand. Unwanted plants are removed about 30 days after planting, traditionally by hand-thinning crews armed with hoes.

The estimated grower cost to hand thin lettuce ranges from $80 per acre to $150 per acre. Automated thinner manufacturers suggest the machines can remove unwanted plants around the same price of hand thinning or at a lower cost.