Lettuce, Sylvesta Butterhead, Organic, Garden Plant

Description

CULTURE: Lettuce is hardy and can be planted as early as the soil can be worked. It is a cool weather crop and grows best at temperatures of 60–65°F (15.5–18.3°C). Careful variety selection is important for hot weather plantings. Sow every 3 weeks for a continuous supply of fresh lettuce.
Pelleted seed requires a little extra attention when it comes to watering, as it performs best with consistent, moderate soil moisture throughout the germination period. An initial watering will split or dissolve the pellet, but if the soil is allowed to dry out before the germination period is over, the seed may receive insufficient moisture for optimal germination.

THERMAL DORMANCY: Lettuce seed can enter thermal dormancy when exposed to high temperatures. Optimum germination results at soil temperatures of 60–68°F (15.5–20°C). The priming process in pelleted lettuce seeds broadens the temperature range in which the seeds will germinate, overcoming some of their thermal dormancy.

TRANSPLANTING: Sow in flats, 1 seed/in., or in ¾” plug trays, barely covering seeds with fine vermiculite, 3–4 weeks before transplanting outdoors. Shade the flats on sunny, warm days if necessary to keep the soil surface cool, below 75°F (24°C), until germination. If sowing into flats, transplant 1–2″ apart into flats, pots, or cell-type containers about 2 weeks later. Harden seedlings by reducing water and temperature for 2–3 days before planting outdoors. Properly hardened transplants can survive temperatures as low as 20°F (-6°C). Transplant iceberg and romaine lettuce 10–12″ apart, in rows 18″ apart. Other types 8–10″ apart in rows 12–18″ apart for full size heads or 6″ apart for mini heads.

DIRECT SEEDING: Seeds germinate even at low, 40°F (4°C), soil temperature, but poorly above 75°F (24°C) depending on the variety and seed lot. Sow seeds 2-3″ apart, rows 12–18″ apart. Cover seed lightly, about 1/8″, and firm soil gently. Thin iceberg and romaine lettuce to one plant every 10–12″, other types 8–10″ for full size heads or 6″ for mini heads. Dry soil must be watered to ensure coolness and moisture, and for uniform germination.

DAYS TO MATURITY: For full-size heads in mild temperatures from direct seeding; subtract 10-14 days if transplanting. Note: Maturity can be 3 or more weeks later in cool weather, and up to 1 week earlier in hot weather.