Lettuce leaf color and texture vary with variety, but all types of lettuce grow best when the soil is kept constantly moist.
Loose-leaf varieties grow tender leaves in dense rosettes, but seldom form crisp inner heads. Some loose-leaf lettuce varieties have superior heat tolerance.
Butterheads and bibb types quickly form small heads of leaves with stout, crunchy ribs. Some varieties have superior cold tolerance.
Romaine lettuce has elongated leaves with stiff ribs. Romaines often tolerate stressful weather better than other types of lettuce.
Crisphead lettuce includes familiar iceberg types, as well as lush and leafy Batavian, or French Crisp, varieties which have great flavor and color, and are easy to grow.
When to Plant
In spring, sow lettuce in cold frames or tunnels six weeks before your last frost date. Start more seeds indoors under lights at about the same time, and set them out when they are three weeks old. Direct seed more lettuce two weeks before your average last spring frost date. Lettuce seeds typically sprout in two to eight days when soil temperatures range between 55 and 75 degrees.
In fall, sow all types of lettuce at two-week intervals starting eight weeks before your first fall frost. One month before your first frost, sow only cold-tolerant butterheads and romaines.
How to Plant
Prepare your planting bed by loosening the soil to at least 10 inches deep. Mix in an inch or so of good compost or well-rotted manure. Sow lettuce seeds a quarter of an inch deep and 1 inch apart in rows or squares, or simply broadcast them over the bed.
Indoors, sow lettuce seeds in flats or small containers kept under fluorescent lights. Harden off three-week-old seedlings for at least two or three days before transplanting. Use shade covers, such as pails or flowerpots, to protect transplants from sun and wind during their first few days in the garden.
Harvesting and Storage
Harvest lettuce in the morning, after the plants have had all night to plump up with water. Wilted lettuce picked on a hot day seldom revives, even when rushed to the refrigerator. Pull (and eat) young plants until you get the spacing you want. Gather individual leaves or use scissors to harvest handfuls of baby lettuce. Rinse lettuce thoroughly with cool water, shake or spin off excess moisture, and store it in plastic bags in the refrigerator. Lettuce often needs a second cleaning as it is prepared for the table.
