Lettuce seeds that have a high germination percentage are not always high in vigor. Low vigor seeds may germinate and emerge from the soil acceptably under favorable conditions, but under unfavorable situations they perform poorly. In recent years, most lettuce growers in the central coast area of California have been using reduced seeding or precision planting techniques. With a reduction in the number of seeds planted per acre, the quality of seeds both in terms of germination and vigor becomes more critical. Rapid emergence of seedlings during the critical stages of emergence, and establishment of the tender plant, is important to help reduce stand losses due to soil crusting, insect and fungi attack.

Mesa 659 lettuce seeds used in this investigation were provided by the Ferry-Morse Seed Company. The Calmar seeds were obtained from experimental plots at the West Side Field Station, Five Points.