Current Cultural Practices in California lettuce require a thinned stand with single plants spaced 12 to 14 inches apart on a 40-inch double-row bed. The ideal situation would be to plant the precise number of seeds to obtain such a stand, but the many hazards to germination, emergence, and plant survival make it impossible to plant consistently to a stand. At present, it appears more practical to precision-plant fewer seeds than are now planted commercially—and then thin to the desired stand with a selective thinner. This is a progress report of work to develop such a planting system. Factors studied were irrigation techniques, chemical weed-control treatments, and the use of covering materials for soil-crust prevention. (Two planters were used, but no effort was made to compare the two machines.)

Spreckels Sugar Company supplied the land and irrigation water for these experiments, and Rain Bird Sprinkler Manufacturing Company supplied the sprinkler heads used in the studies.