Lettuce is a fairly hardy, cool-weather vegetable that thrives when the average daily temperature is between 60 and 70°F. It should be planted in early spring or late summer. At high temperatures, growth is stunted, the leaves may be bitter and the seedstalk forms and elongates rapidly. Head lettuce must be transplanted in most locations and requires more care than other types of lettuce.

Start transplants for a spring crop indoors or in a cold frame and set them in the garden as early in the spring as the weather settles. Harden transplants outdoors so that they become acclimated to the conditions under which they will be grown, but do not allow growth to stop entirely. Cos, butterhead and leaf varieties also can be transplanted for earlier harvest. In the heat of summer, lettuce seedlings started in a protected location in the shade can be transplanted later into moderate sites for some limited success.

Plant seeds 1/4 to 1/2 inch deep (10 seeds per foot) in single, double or triple rows 12 to 18 inches apart. Thin seedlings to 4 inches apart for leaf lettuce and 6 to 8 inches apart for Cos or Butterhead. The seedlings removed may be transplanted or eaten. Transplant Crisphead seedlings 10 to 12 inches apart in the row. Butterhead varieties form small, loose heads that weigh 4 to 8 ounces at harvest (60 to 70 days). The innermost leaves, that tend to blanch themselves, are a delicacy. Cos varieties have an upright growth habit and form a long, medium-dense head.

Nutrition Facts (One cup raw leaf lettuce, chopped) Calories 9 Dietary Fiber 1.3 Protein 1 gram Carbohydrates 1.34 grams Vitamin A 1456 IU Vitamin C 13.44 Calcium 20.16 Iron 0.62 Potassium 162.4 mg

(Approximately 21,250 to 41,250 seeds per oz.)