Botanical Name: Lactuca sativa
Days to Maturity: 20–65 days
Native: Unknown; lettuce has been in cultivation for a long time.
Hardiness: Frost-tolerant annual
Plant Dimensions: 6"–10" tall, 8"–10"wide
Variety Information: Upright heads have bronze-red leaves and a green heart; develops best color in cool weather. 'Rouge d´Hiver' is a compact lettuce; a French heirloom from the 1800s.
When to Sow Outside: RECOMMENDED. 2 to 4 weeks before your average last frost date, and when soil temperature is at least 40°F, ideally 60°–70°F. Successive Sowings: Every 3 weeks until 4 to 6 weeks before your average first fall frost date. Mild Climates: Sow in fall and winter for cool season harvests.
When to Start Inside: 4 to 6 weeks before your average last frost date, and in summer when soil temperatures are too warm (above 80°F) to germinate lettuce seed.
Days to Emerge: 5–10 days
Seed Depth: Surface to ⅛"
Seed Spacing: A group of 3 seeds every 10"
Row Spacing: 10"
Thinning: When ½" tall, thin to 1 every 10"
Harvesting: Harvest in the morning, by cutting off at ground level. If regrowth is desired, cut the leaves higher, at 2". For a continual supply, outer, individual leaves can be harvested at any stage of maturity, but leave at least half of the plant for regrowth.