Butterhead Lettuce

Butterhead lettuce, also called Bibb or Boston lettuce, is a loose-heading type with dark green leaves that are somewhat thicker than those of iceberg lettuce. Its leaves develop a light yellow, buttery look, and it is a cool-season vegetable native from the Mediterranean to Siberia.

Sowing. For a spring crop sown outdoors, plant seed about ¼ to ½ inch (0.6 to 1.3 cm) deep, two to three weeks before the last spring frost. You can also sow butterhead as soon as the soil can be worked in spring or in late summer. Starting seed indoors six to eight weeks before the last frost, for later transplanting, is another option.

Germination. Seeds usually emerge in about 7 to 10 days. Optimum germination happens at soil temperatures of 60 to 68 °F (16 to 20 °C), and high heat can push seed into dormancy.

Spacing. The sources differ. One suggests 8 to 12 inches (20 to 30 cm) between plants in the row, while another gives 4 to 10 inches (10 to 25 cm) in the row for butterhead.

Containers. Butterhead can be grown in a container at least 2 quarts (about 1.9 litres) in volume and 6 to 8 inches (15 to 20 cm) deep.

Light and soil. Give it full sun to partial shade. Plant in rich, well-drained soil and aim for a pH between 6.0 and 6.5.

Watering. Keep the soil consistently moist, because lettuce has shallow roots. Use frequent, light watering rather than heavy soakings, and avoid overwatering. Water in the morning so the foliage dries before dark.

Heat. Butterhead tends toward bitterness in hot weather, and Bibb lettuce becomes bitter readily once temperatures go above 75 °F (24 °C). Tall crops that shade the lettuce during the hottest part of the day can help.

Pests. Aphids are a common problem, and slugs and snails may feed on the foliage.

Diseases. Damping-off is a serious disease of young seedlings, while mildews and sclerotinia are serious on mature plants. Bacterial leaf spot begins as small water-soaked spots that join into lesions, and cool, wet weather makes it worse, especially between 50 and 75 °F (10 and 24 °C). Spread is mostly by rain splash and sprinkler irrigation, so avoid sprinklers and start with clean seed.

Pick the outer leaves first so the center keeps growing. You can also cut the whole plant at or just above the soil surface. Bibb lettuce is ready when the leaves begin to cup inward to form a loose head.

Refrigerator. Keep butterhead cold at 35 to 40 °F (1 to 4 °C) with high humidity and no standing water. Delicate types such as butterhead keep for less time than sturdier heads. Leaf and Bibb types can keep as long as four weeks if the leaves are dry when bagged.

Its poison characteristics are rated low severity. For people who handle the plant, contact with the sap can cause skin irritation, which is contact dermatitis.