🥕 Lettuce
Lactuca sativa
vegetables leafy green
☀️ Sun
Full sun in cool weather; partial shade in warm weather (shade delays bolting in summer); 4–6 hours sufficient
💧 Water
Medium–high; 1 inch per week; consistent moisture for tender, non-bitter leaves; water stress causes bolting and bitterness
🗺️ Zones
2, 3, 4, 5, 6, 7, 8, 9, 10
🪴 Soil Type
Rich, moisture-retentive loam with high organic matter; lettuce is shallow-rooted and needs consistent access to nutrients near the surface
🧪 Soil pH
6.0–7.0 (slightly acidic to neutral)
💧 Drainage
Moisture-retentive but not waterlogged; lettuce thrives in consistently moist soil
📏 Spacing
Loose-leaf: 4–6 inches apart; romaine/butterhead: 8–10 inches; crisphead/iceberg: 12–14 inches; rows 12–18 inches apart
📅 Days to Maturity
30-50 days (from seed) for leaf lettuce; 55-75 days for head lettuce
🍴 Edible Parts
🍽️ ["Leaves"🍽️ "Heart (core \u2014 edible🍽️ slightly bitter)"🍽️ "Stems (lettuce stem lettuce/celtuce \u2014 different variety🍽️ Liang ye wosun)"]
🤝 Companions (7)
Lettuce and carrots share water/soil needs; lettuce is shallow-rooted, carrots are deep; lettuce shades soil keeping carrot roots cool
Radishes mark rows for slow-germinating lettuce; radishes are harvested before lettuce needs space; radishes repel flea beetles
Onions repel aphids and slugs from lettuce; complementary root depths
Lettuce grows well under strawberries; strawberries act as living mulch; both prefer cooler conditions
Repels aphids; may improve lettuce flavor
Lettuce grows in the shade of trellised cucumbers; cucumbers benefit from lettuce's ground cover
Trap crop for aphids; repels whiteflies
⚠️ Keep Apart (3)
Some sources report parsley may cause lettuce to bolt prematurely (conflicting evidence)
Allelopathic
⚠️ Brassicas (conflicting)
Some sources say brassicas release root exudates that inhibit lettuce germination; others report no effect
💊 Medicinal Uses
["Contains lactucarium ('lettuce opium') \u2014 mild sedative/sleep aid (much milder than historical claims); wild lettuce (Lactuca virosa) is more potent", "Good source of vitamin A and vitamin K", "High water content \u2014 hydrating; very low calorie", "Contains small amounts of folate and manganese"]
📝 Notes
Four main types: Loose-leaf (cut-and-come-again), Romaine/Cos (upright, crunchy), Butterhead/Bibb (loose heads, tender), Crisphead/Iceberg (tight heads, crunchy). Lettuce is a cool-season crop — bolts quickly in heat (above 75°F). Succession plant every 2 weeks for continuous harvest. Cut-and-come-again harvesting extends production (cut outer leaves, leave center). Seed needs light to germinate — surface sow or barely cover.