2. Soil preparation and fertilization. Choose plots with fertile soil, good fertilizer and water conservation, convenient irrigation and drainage, and no crops for planting the same crop 1 year or more. Dig deep into the soil and apply 3500 kg of decomposed organic fertilizer, 50 kg of calcium superphosphate and 50 kg of compound fertilizer per mu.
Step 3 plant. When the seedlings are 25-30 days old, they can be planted when 4-5 true leaves grow. If the seedling age is too long, it is easy to "escape" when the seedling grows in vain. The planting row spacing is generally 30-35cm, the spacing between plants is 25cm, and 6000-7000 plants are planted per mu. The planting time can be cloudy or after 4 pm.
4. On-site management.
(1) water. Root water should be poured immediately after planting, and dilute manure water should be poured once two days after planting to promote the delay of seedling emergence.
(2) fertilization. After the seedlings grow slowly, apply available nitrogen fertilizer, and then reduce watering appropriately to keep the soil moist. Before and after the fruiting stage, apply heavy fertilizer for 2-3 times, and apply 30%-40% decomposed human and animal manure of 3000-4000 kg or urea 15 kg per mu. Uniform supply of fertilizer and water to prevent stem cracking.
(3) farming. Fertilization, watering and rainfall after planting are easy to cause soil hardening on the border. After slow planting, timely intertillage combined with fertilization is beneficial to squatting seedlings, promoting good root development, increasing rosette leaves, and making young stems grow healthily without jumping up.
5. Prevent bolt connection. In order to prevent autumn lettuce from bolting, when the lettuce stems begin to swell, chlormequat chloride can be sprayed on the leaves for 2-3 times to effectively inhibit bolting and increase the weight of the stems. Bolting in the late growth stage can remove flower buds differentiated from tender stems and promote the continuous growth of stems.