2. Sowing period to determine. Spring lettuce can be in December to the second year in March greenhouse seedlings, but also in mid-February to late March open field seedlings.
3. Cultivate strong seedlings. (1) land preparation. Selected high and dry terrain, well-drained plots for seedbeds. 5 ~ 7 days before sowing per mu of rotting organic fertilizer 2000 ~ 3000 kg, 25 kg of compound fertilizer as base fertilizer. In the ground before the application of deep turning, leveling and fine, covered with plastic film waiting for sowing. (2) sowing. Spring away from the shoots greenhouse seedling sowing, first unveil the film on the seedling bed, watering the bottom of the water, until the water seeps down, the seeds mixed in a small amount of fine sand or fine soil mixed and sown. 10 square meters of seedbed sowing seeds 25 ~ 30 grams. After sowing mulch 0.5 cm or so, cover the film tightly, and at night cover the shade net or straw thatch insulation. Open-ground seedlings covered with a small arch. Before the seedlings emerge from the soil, late uncovered early cover mulch, to maintain the temperature of the seedbed. Seedlings out of the ground appropriate ventilation, daytime bed temperature 12 ℃ ~ 20 ℃, night 5 ℃ ~ 8 ℃.
4. Planting. Planting, choose the soil with good drainage conditions, 4000 to 5000 kilograms of rotted organic fertilizer per mu. Deep turning and leveling, made 1.2 ~ 1.5 meters wide raised beds. Before starting seedlings, water the seedbed first. Spring lettuce seedlings age 25 ~ 30 days, 5 ~ 6 leaves when planting, plant spacing 20 cm × 27 cm, the depth of buried to the base of the first petiole is appropriate. Lettuce with leaves on the market, plant spacing 15 cm × 20 cm. Cultivation of mulch cover, bottom fertilizer should be a full application, and cover the film, rainy day drainage to prevent stains.