The ideal time to plant lettuce is in the spring or fall when temperatures range from 45 to 65 degrees Fahrenheit. A gardener can start seeds indoors four to six weeks before the last frost of the season.
Lettuce thrives in well-drained, fertile soil. Fine soil with no clumping helps increase seed germination. Thinning the seedlings that grow close together gives the plant enough space to grow to full potential. Lettuce needs water when the leaves begin to wilt and requires partial sunlight to grow. A person can harvest outer leaves for use as the lettuce grows and harvest the whole plant when the center is firm.