History of Mechanized Harvesting of Processing Tomatoes in California

Mechanization of California's processing tomato crop was hastened by the phase out of the Bracero agricultural labor program ending by 1964.  Decades earlier, UC Davis plant breeder Jack Hanna had the insight to begin selecting for plant horticultural characteristics that included a determinant vine type with a concentrated fruit set and more durable fruit to withstand the bruising mechanical handling.  By 1949, the breeding program was partnered with efforts by UCD Agricultural Engineer Coby Lorenzen and colleagues to design a prototype, once-over harvester. 

 Prior to mechanization, tomatoes were hand picked into wooden boxes each containing about 50 pounds of fruit.  Fields were commonly harvested multiple times as vines had indeterminant growth.  Even with continuous setting fruit, average production was below 20 tons per acre. To hand harvest 75 tons per day, a 30-person crew of efficient, durable workers were needed. 

 The first commercial mechanical harvester was showcased in 1960 by Blackwelder under a patent agreement with UCD.  Over a dozen sorters manned the first harvesters.  The crew was capable of harvesting 75 tons of fruit per 10-hour day.  Since the crew rode on the machine and worked under a shade structure, the labor force included women and older teenagers as well.  Fruit were harvested into wooden bins which held over 1,000 pounds of fruit. 

 Current harvest machines include electronic sorters to remove dirt clods and under-colored fruit, have aggressive shaker systems to remove fruit from vines and require less maintenance.  In California, the sole remaining harvester manufacturer is California Tomato Machinery that has patents from former major manufacturers Johnson, Blackwelder and FMC.  Machine harvest output increased to over 75 tons per hour under ideal conditions, but can easily average 25 tons per hour over the season.  Harvest output also increased with the addition of a night crew from a traditional day-only shift.  Sorter crews have been reduced to about 2 to 4 persons per machine.  Fruit is harvested into 25,000-pound capacity tubs set directly on tandem trailers for highway transport.

 What’s in the future?  Electronic sorting will likely advance to detect an array of fruit defects.  Perhaps pickup mechanisms might change to be similar to small grain stripper headers where only grain is collected, without high volumes of plant debris.  Changes may be needed to adjust to modifications from conservation tillage and sustainable agricultural practices. 

 Improvements in harvesting efficiency will continue to be coupled with improvements from plant breeding programs.