🌿 ArbGard Online

Romaine lettuce is an upright, crisp-leaved cultivar prized for its sturdy texture, sweet flavour, and use in salads and Caesar dressing. Gardeners favour it for its reliability, productivity, and ability to tolerate light frost. It's a cool-season crop that thrives in spring and fall gardens across zone 7.

Romaine seeds germinate in 7–10 days at soil temperatures of 60–70°F (ideally around 65°F). They prefer light and will germinate faster under 12+ hours of light daily; avoid burying seeds too deep as they need light exposure. Do not soak seeds beforehand unless germination is delayed by heat stress.

Direct sow seeds ¼ inch deep in rows or broadcast, spacing plants 6–8 inches apart (thin after sprouting). Sow in spring 2–3 weeks before the last frost, or in late summer for fall harvest. For transplants, start seeds indoors 4–6 weeks before transplanting out; transplant when seedlings have 2–3 true leaves, spacing 6–8 inches apart. Succession plant every 2 weeks for continuous harvest.

Water regularly to keep soil consistently moist but not waterlogged; inconsistent moisture causes bitterness and bolting. Apply 1–2 inches of compost or balanced fertilizer (10-10-10) at planting, then side-dress with nitrogen every 3 weeks if growth slows. Romaine is cold-hardy and actually improves in flavour after light frosts. Watch for aphids, slugs, and downy mildew in wet conditions; use insecticidal soap and ensure good air circulation. Avoid heat stress above 75°F, which triggers bolting.

Begin harvesting outer leaves when plants are 6–8 inches tall (about 40–45 days), or wait until full maturity at 60 days for whole-head harvest. Cut heads at the base in early morning for maximum crispness. Whole heads keep 1–2 weeks in a plastic bag in the refrigerator; individual leaves last 3–5 days. Harvest before temperatures consistently exceed 75°F or plants will bolt and turn bitter.