Growing Lettuce: Types, Timing, and Harvest Tips

A seed catalog reveals enough lettuce variety for a crisp, colorful salad bowl all season. Four principal types:

• Crisphead: Most challenging. Heads form best at 55°–60°F monthly averages. In mild climates, long season; in hot summers, timing is critical. Varieties: ‘Great Lakes’, ‘Summertime’, ‘Nevada’.
• Butterhead/Boston: Loose heads, green outer leaves, yellow inner. ‘Bibb’, ‘Buttercrunch’, ‘Tom Thumb’. ‘Mignonette’ resists bolting in heat.
• Loose-leaf: Rosettes, not heads. Best heat tolerance. ‘Blackseeded Simpson’, ‘Green Ice’, ‘Oak Leaf’ (green); ‘Salad Bowl’ (deeply cut); ‘Prizehead’, ‘Ruby’ (red-tinged).
• Romaine: Erect cylindrical heads, green outer, whitish inner. Moderate heat tolerance. ‘Medallion’, ‘Olga’, ‘Parris Island’.

Red-leaved varieties add color: butterheads ‘Freckles’, ‘Merveille des Quatre Saisons’, ‘Perella Red’; loose-leaf ‘Lollo Rosso’, ‘Red Oak Leaf’, ‘Red Sails’, ‘Ruby’; romaines ‘Rouge d’Hiver’, ‘Sierra’.

Mesclun mixes combine loose-leaf and romaine lettuces with mustards, arugula, cress, chicory, radicchio, mizuna.

Culture

All need loose, well-drained soil. Barely cover seeds. Space loose-leaf 4 inches apart; thin others to 1 foot. Grow mesclun in 4-inch-wide blocks, no thinning. Sow every 2 weeks for continuous harvest.

Cold-winter regions: Sow after frost, as soon as soil works; short summers: start indoors, transplant after last frost.

Mild-winter, cool-summer: Spring sow for spring/summer; late summer/early fall sow for winter.

Mild-winter, hot-summer: Winter and early spring crop only.

Feed lightly and frequently. Control snails, slugs, earwigs. Harvest at good size; mature lettuce bolts quickly, turning bitter. With loose-leaf and mesclun, clip outer leaves as needed.