Lettuce

Lettuce has held symbolic and practical roles throughout history. In ancient Egypt, it was associated with fertility and ritual offerings. Today, lettuce is a universal emblem of healthy eating, featured in cuisines from Mediterranean mezze to American fast food. Its presence in art and language—such as the French "laitue" and Spanish "lechuga"—reflects its global reach and cultural integration.

• Lettuce was first cultivated for its oil-rich seeds before its leaves became a culinary staple.
• Iceberg lettuce, famed for its crispness, was developed in the early 20th century and revolutionized salad culture.
• Stem lettuce, or "celtuce," is prized in Chinese cuisine for its edible stalks.
• Lettuce is among the lowest-calorie vegetables, with over 90% water content.
• Bolting, triggered by heat, causes lettuce to become bitter and produce flowers.

Lettuce is exceptionally low in calories and rich in water, making it a hydrating food choice. It provides dietary fiber, vitamin K, vitamin A, folate, and small amounts of vitamin C and potassium. Its nutrient density varies by type, with darker leaves generally offering more vitamins and antioxidants. Lettuce supports digestive health and is favored in weight-conscious diets.

Lettuce is a foundation for salads, from classic Caesar to mixed greens. It adds crunch to sandwiches, wraps, and burgers, and is used as a bed for appetizers or grilled meats. Romaine can be grilled or sautéed, while stem lettuce is stir-fried in Asian cuisine. Pre-cut and bagged lettuce mixes offer convenience for quick meals and entertaining.

Lettuce thrives in cool climates, preferring temperatures between 15–20°C. It is grown as an annual crop, with optimal yields achieved in well-drained, fertile soils. Heat stress can cause bolting and bitterness, so growers often plant in spring or autumn. Commercial production averages 20–35 tons per hectare. Lettuce is sensitive to pests like aphids and diseases such as downy mildew, but resistant cultivars and crop rotation help manage risks. Harvesting is typically done by hand or machine, with rapid cooling essential to preserve quality.

• Fresh whole heads (butterhead, iceberg, romaine)
• Loose-leaf (sold by weight or bunch)
• Pre-cut and bagged mixes (ready-to-eat salads)
• Processed forms (shredded, chopped for food service)
• Specialty types (stem lettuce, heritage varieties)

• Iceberg: Dense, pale green heads; crisp texture.
• Romaine (Cos): Upright, elongated leaves; sturdy and flavorful.
• Butterhead (Boston, Bibb): Soft, tender leaves; mild taste.
• Batavia: Intermediate between crisphead and loose-leaf; slightly frilled edges.
• Little Gem: Miniature romaine; sweet and crunchy.
• Celtuce: Grown for edible stems; popular in Chinese cuisine.

Lettuce is vulnerable to aphids, leaf miners, and slugs, as well as fungal diseases like downy mildew (Bremia lactucae) and lettuce mosaic virus. Breeding for disease resistance, crop rotation, and integrated pest management are key strategies for growers. Resistant cultivars help reduce losses, but vigilance is required, especially in humid or warm conditions.

Lettuce is known by different names worldwide: "laitue" in French, "lechuga" in Spanish, "salat" in German, and "yēcài" in Chinese. Regional preferences influence the popularity of types—romaine is favored in Mediterranean diets, iceberg dominates North American markets, and stem lettuce is a specialty in East Asia. Heritage varieties and local cultivars add diversity to global lettuce consumption.

Choose lettuce with crisp, vibrant leaves free of wilting or browning. Store unwashed heads in the refrigerator, ideally in a sealed container or produce drawer, to maintain freshness for up to two weeks. Wash just before use to prevent spoilage. For longer storage, keep leaves dry and avoid crushing. Pre-cut mixes should be consumed promptly for optimal quality.