Non-pollution cultivation techniques of summer lettuce
1. Select suitable varieties should use heat-resistant, rapid growth at high temperatures, leaves and more tender, good quality varieties. Such as heat-resistant white leaf tip, bitter buckwheat leaves, white leaves, heat-resistant white skin and so on.
2. Timely sowing of hot water lettuce Lettuce generally from April to July, staged live broadcast in batches, a few high-density planting. Select slightly acidic soils that meet the conditions for the production of pollution-free vegetables and good drainage conditions. 7 to 10 days before sowing, cultivating and cultivating ridges, and applying enough base fertilizer, applying 4,000 to 5,000 kilograms of organic fertilizer or 50 kilograms of compound fertilizer per 666.7 square meters. After flattening before the preparation, it shall be flattened, covered with plastic film and sown. In the middle of April to May, the temperature is still relatively low, and seeds do not need low temperature germination. The seeds are soaked in warm water at 25Â°C to 30Â°C for 6 to 7 hours, then placed in a refrigerator at room temperature or in the refrigerator for a day and night. The humidity is maintained. After 2 to 4 days, 70% of the seeds are whitened, and they are sown on cloudy days. Wet seeds can also be sown in the middle and fourth months of May to May, and removed after the start of emergence. From late May to early July, depending on the weather, if it is hot and dry, use a small shed or flat shed to cover the shade net until it emerges or two true leaves. Rainy days can also be covered with a small shade shed to protect against rainwater and seedlings. Due to the use of direct seeding, the seeding rate can be reduced by 5 to 10 grams per 10 square meters, that is, 66,600 square meters sowing field 300600 grams.
3. Cultivation Management Seedlings after emergence, and time seedlings, generally the first time between the two true leaves for the first seedlings, between the dense, overcrowded seedlings; in 4 to 5 true leaves when the second time the seedlings, and according to Seedlings 10 cm away from the seedlings, between the weak seedlings and excessive seedlings. Between the strong seedlings can also be planted at a high density of about 10 centimeters per plant, planting 30,000 to 35,000 plants per 666.7 square meters. Every time the seedlings, especially after the seedlings are sown and transplanted slowly, they should be poured in time and put through decomposing and dilute waste water, so that it will be poured and fertilized, and watering and fertilizing will be carried out at the same time to keep the soil moist. In the rainy days, the gutters should be drained in time. About 15 days before planting, the manure was stopped and 0.5% urea water was changed.
4. Appropriate harvesting 25 days after the start of seedling or transplanting, according to the market conditions, the acquisition of tender plants or semi-strain plants will begin. If harvesting is not timely, it may cause convulsions and degrade quality. Usually collected at one time, remove the roots and yellow leaves, rinse with clean water, tie it into a 500 grams of a listing for sale.
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