Heat-tolerant romaine for hearts.
High-yielding, upright, dense heads produce long, uniform hearts with good flavor. Ideal for spring, summer, or fall harvests. Similar to Helvius, which it replaced, but longer hearts and more attractive plants. Utility Patent granted. High resistance to downy mildew races EU 16, 17, 19, 21, 23; US 1–6. MT0-30. Also available with NOP-compliant pelleting. Avg. 23,900 seeds/oz. Packet: 500 seeds.
SCIENTIFIC NAME: Lactuca sativa
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 (16-18°C). Careful variety selection is important for hot weather plantings. Sow every 3 weeks for a continuous supply of fresh lettuce.
THERMAL DORMANCY: Lettuce seed can enter thermal dormancy when exposed to high temperatures. Optimum germination results at soil temperatures of 60-68°F (16-20°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, 4 seeds/in., or in 3/4" 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 6 seeds per foot, 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.
SALAD MIX/BABY LEAF: Sow in a 2-4" wide band, about 60 seeds/ft.
MT0 SEEDS: A variety’s description followed by MT0-30 indicates that the seed offered for sale has been tested for the presence of Lettuce Mosaic Virus and that no LMV was found in a sample of at least 30,000 seeds.
NOTE: A disease-free test result does not guarantee a seed lot to be disease-free, only that in the sample tested, the pathogen was not found.
DAYS TO MATURITY: For full-size heads in mild temperatures from direct seeding; for days to maturity from transplant date, subtract 10–14 days. NOTE: Maturity can be 3 or more weeks later in cool weather, and up to 1 week earlier in hot weather.
AVG. DIRECT SEEDING RATE: For full-size heads (precision seeded): 1,000 seeds/160′, 1 oz./3,000′, 10 oz./acre 2" apart in rows 18" apart. For baby leaf: 1,000 seeds/16′, 1 oz./400′, 1 lb./6,400′ at 60 seeds/ft.
TRANSPLANTS: Avg. 16,000 plants/oz.
SEED SPECS: SEEDS/OZ.: Avg. 17,800.
PACKET: 500 seeds, unless otherwise indicated.