Lettuce grows best in cool weather. Plant as early as possible and successively every two weeks in spring, and again in late summer for a fall crop. Head lettuce may be started indoors for earlier harvest. A packet contains about 1000 seeds except where noted and will sow 50 ft., an ounce a 300 ft. row. There are approximately 20,000 to 25,000 seeds in a ounce. Plant more than one variety for a longer harvest season.