How to Grow Head Lettuce: Methods and Key Technical Points

Head lettuce, also known as round lettuce, is a vegetable similar to lettuce, and it is widely grown because of its good taste and ease of cultivation. So what are the methods for growing head lettuce?

1. Site selection and land preparation

Choose a plot that is sheltered from the wind, faces the sun, and has a water source nearby for planting. The soil is required to be rich in organic matter, loose in texture, and strong in water and fertilizer retention, with a pH of 5.5-7.0. The previous crop is preferably corn or potato. There must be no pesticide residues such as pursuit, chlorimuron-ethyl, or chlorsulfuron. Then carry out deep loosening and land preparation, apply sufficient base fertilizer, and level the ground.

2. Sowing and seedling raising

(1) Seed selection: You may choose one of the following varieties for planting: Zhonggan No. 11, 8398, Qingfeng, and Zhonggan No. 8. Among them, Zhonggan No. 11 is suitable for open-field and greenhouse cultivation, and its yield per mu is about 3500 jin.

(2) Seed treatment: Soak the seeds for 12 hours, then rinse them clean with clear water, wrap them in wet gauze, and treat them for 2d under low-temperature conditions of 5-6°C. Take them out for sowing when most of the seeds begin to sprout. After sowing, the soil cover should not be too thick, generally about 0.5-1cm. In summer and autumn, when temperatures are high and there is a lot of rain, cover with a shade net after sowing for shading.

(3) Sowing time: For the spring crop, sow and raise seedlings from February to April, and harvest from May to June; for the autumn crop, sow and raise seedlings from late July to late August, and harvest from October to November. (4) Sowing method: Use the method of raising seedlings and transplanting. Before sowing, water thoroughly to moisten the bottom soil, spread a 0.5cm layer of fine soil, sow dry seeds by broadcasting, using 0.002 jin of seeds per square meter. To sow evenly, mix the seeds with sand and broadcast in two batches, then cover with 0.5cm of fine soil, just enough to cover the seeds tightly, and cover with a layer of straw curtain on top to retain moisture. After seedlings emerge in 5-7d, gradually remove the covering, and pay attention to rain and sun protection.

(4) Seedling management: After sowing and before emergence, keep the soil moist. After sowing, sprouts appear in 2-3d, and the straw curtain can then be removed; if the straw curtain is not removed in time, leggy seedlings are likely to occur. After emergence, water once every morning and evening. About two weeks after sowing, thin the seedlings, removing weak seedlings and leggy seedlings, and keeping strong healthy seedlings. After 15d of seedling age, diluted urea may be applied. The seedling stage is generally 25-30d.

3. Field planting

For early-maturing varieties, use double-row planting, with a row spacing of 35cm and a plant spacing of 25-30cm, planting 4000-5000 plants per mu; for mid-maturing and late-maturing varieties, plant more sparsely to allow full growth. High-ridge cultivation may be used, with a row spacing of 40cm and a plant spacing of 30-35cm, planting 3000-3700 plants per mu. For 3-4d after planting, water an appropriate amount every morning and evening to increase the survival rate. If there are missing plants, replant them in time.

4. Field management

Head lettuce has a relatively long growth period, so fertilizer should be applied several times. Generally, topdress once every 7-10d. For 4-6d after planting, apply a light application of quick-acting nitrogen fertilizer to promote root and leaf growth. When heading begins, increase the application of potassium fertilizer. Before the plants close the rows, apply a heavy fertilizer, using 20 jin of compound fertilizer plus 7.5 jin of potassium chloride per mu. A shallow furrow may be opened between the two rows for application, then cover with soil to avoid fertilizer contacting the roots. From planting to the beginning of heading, keep the soil moist. Entering the rosette stage, strictly control moisture to avoid disease. During the heading stage, avoid water accumulation on the bed surface or water contacting the head; during this period, furrow irrigation is suitable. Water should be controlled 15d before harvest. Head lettuce has a shallow root system, so cultivation should not be too deep to avoid damaging the roots, and cultivation should be carried out before the plants close the rows.

5. Harvest

From planting to harvest, head lettuce takes about 55d for early-maturing varieties, about 65d for mid-maturing varieties, and 75-85d for late-maturing varieties, but it is better to harvest a few days earlier. Harvest standard: you can press obliquely from both sides of the head with both hands, and it is suitable if it feels firm. Control water 15 before harvest. At harvest, select plants with tight heads and cut them off from the ground, strip off the old leaves, and keep 3-4 outer leaves to protect the head. The suitable temperature for transport and storage is 1-5°C.

Overall, head lettuce is still quite easy to grow. As long as you choose good land and good seeds, sow them into the soil, and finally, after the seedlings emerge, do a good job with water and fertilizer management and pest and disease control, the vegetable will grow.