Detailed Explanation of Year-Round Cultivation Techniques for Pure-Fragrant Leaf Lettuce

 Pure-Fragrant leaf lettuce produced by the Vegetable Research Institute of the Chinese Academy of Agricultural Sciences has been planted in Chuanshan Township, Qixing District for more than three years. This variety has strong adaptability, a crisp and fragrant taste, good quality, and a high market price, and is deeply loved by farmers and consumers. The year-round cultivation techniques for leaf lettuce are summarized as follows.

1. Variety characteristics  Plant height 30-40cm, spread 20-30cm, leaves lanceolate, about 40cm long and 6-10cm wide, green, leaf surface smooth, cold-resistant, heat-tolerant, bolting-resistant, strongly adaptable, and can be cultivated year-round in open fields and protected areas. Seed rate per mu is 30-40g. 2. Year-round cultivation techniques  2.1 Early spring sowing: from January to March, sow and raise seedlings in a medium shed. Build 2 beds in a standard shed, open a ditch in the middle, deep-plow and build the beds, water thoroughly, broadcast the seeds in the beds, cover with seed soil just enough to cover the seeds, and lay plastic film flat (2 layers of film and 1 layer of ground film). Seedlings generally emerge in 10-15 days; in cold rainy weather, emergence takes longer. After the seedlings emerge uniformly, remove the ground film, ventilate and exchange air, prevent high-temperature damage to seedlings during the day, and prevent freezing injury at night.  2.2 Summer sowing: from April to June, raise seedlings in the open field. Choose high ground, 2m including ditches, deep-plow and apply decomposed barnyard manure, build beds and level them. Soak the seeds for 3 hours, and sow after the seeds are air-dried. Water the seedling bed thoroughly, scatter the seeds on the bed surface, cover well with seed soil, and water thoroughly. In case of high temperature and drought, cover the bed with a shade net, uncover the net in the morning and evening after the seedlings emerge uniformly, and keep fertilizer and water in the seedling bed moderate, not too dry.  2.3 Autumn sowing: from July to September, leaf lettuce seedling raising requires seed soaking and germination. The method is to wrap the seeds in gauze, soak them in water for 3-4 hours, then take them out and put them in the refrigerator compartment for 10-15 hours. Sow when 75% have sprouted. For autumn sowing and seedling raising, it is best to use a small arched shed or a large shed. After emergence, pay attention to soil moisture, not too dry or too wet, and remove weeds promptly to ensure smooth drainage.  2.4 Autumn-winter sowing: in October, seedlings can be raised in the open field; in November and December, seedlings can be raised in a large shed. The method is the same as spring sowing; November-December is the same as early spring sowing.  3. Transplanting and setting out  Before setting out, deep-plow and apply sufficient base fertilizer. Generally apply 3000kg of decomposed barnyard manure per mu and 80-100kg of ammonium bicarbonate, 2m including ditches, with deep ditches and high beds. Transplant when seedlings have 4-5 leaves. The seedlings should be strong, with plant spacing and row spacing of 10-15cm, cultivated on flat beds. 3.1 Winter sowing: transplant in a large shed and cover with ground film. They can be marketed in about 30 days, with a yield of 1500-18000kg per mu.  3.2 Spring sowing: transplant in the open field, apply sufficient decomposed barnyard manure, and apply 80kg of ammonium carbonate per mu. After setting out, water thoroughly to settle the roots. In case of drought, promote growth with fertilizer and water. They can be marketed in 25-30 days, with a yield of 1800-2000kg per mu. 3.3 Autumn sowing: July-September is the season of high temperature and drought, and there are often rainstorms. After transplanting, water thoroughly to establish the plants, cover with a shade net for 5-7 days, and after the plants are established, remove the shade net on cloudy and rainy days. Moderate fertilizer and water are beneficial to the normal growth of leaf lettuce. They can be marketed in 20-30 days, generally with a yield of 1600-1800kg per mu.  3.4 Autumn-winter sowing: transplant in the open field from October to November. In December, when cold waves strike, they need to be transplanted in a large shed. They can be marketed in 25-30 days, with a yield of about 1500kg per mu.  4. Pest and disease control  The main disease of leaf lettuce is downy mildew, which occurs more in early spring and needs to be controlled with agents such as carbendazim. The main pest is aphids, which can be controlled with aphid killers such as Shachongling and Dagongchen.  5. Harvest  Pure-Fragrant leaf lettuce is generally harvested 20-30 days after setting out. After more than ten leaves have formed, it can also be harvested and marketed at any time according to market demand.