What are the summer lettuce planting and management methods?
How should lettuce be managed when planted in summer? Please give guidance. The summer lettuce planting and management methods are as follows: First, pay attention to fertilizer and water management. Because summer temperatures are high, light is intense, ground evaporation is large, and crop transpiration is also high, frequent watering is needed in the early stage after transplanting to keep the soil moist. Entering the rainy season in July to August, after each...
How should lettuce be managed when planted in summer? Please give guidance.
The summer lettuce planting and management methods are as follows:
First, pay attention to fertilizer and water management. Because summer temperatures are high, light is intense, ground evaporation is large, and crop transpiration is also high, frequent watering is needed in the early stage after transplanting to keep the soil moist. Entering the rainy season in July to August, after each heavy rain, drainage should be carried out promptly and cool water should be irrigated to lower the temperature so as to protect the leaves. In the later stage of growth, water should be properly controlled, and no watering should be done 2 to 3 days before harvest to prevent head splitting. Lettuce has a relatively short growth period, so topdressing should mainly use chemical fertilizers, but attention should be paid to increasing potassium fertilizer to balance nitrogen and potassium, about 15 kg each time.
Second, pay attention to the prevention and control of pests and diseases. In summer, lettuce diseases are mainly downy mildew, viral disease, and gray mold, as well as sclerotinia rot and leaf spot. Downy mildew can be controlled with 75% chlorothalonil 600 times solution, or 40% enhanced ridomil 500 times solution, or 58% metalaxyl-mancozeb 500 times solution; gray mold can be controlled with 50% procymidone, or 50% iprodione 1000 to 1500 times solution, or 50% thiophanate-methyl 500 times solution; for the control of viral disease, in addition to selecting disease-resistant varieties and disease-free good seeds, it should also be combined with the control of aphids, using fenvalerate, menazon, or pirimicarb, etc., to promptly control aphids and eliminate transmission. In addition, attention should also be paid to the prevention and control of physiological diseases and nutrient deficiency symptoms. For example, boron deficiency in lettuce often causes slow growth of veins and leaf margins in new leaves, wrinkling and curling of the leaf surface, and uneven leaf color, resembling the symptoms of mosaic virus disease; in severe cases, leaf tips and margins scorch, and terminal bud growth is inhibited or dies. Therefore, attention should be paid to boron application. Various organic fertilizers contain boron. When necessary, increase the application of borax as base fertilizer or spray boron fertilizer on the leaves.
For summer cultivation, generally little or no intertillage is done to prevent increasing soil temperature. Those not covered with plastic film should mainly rely on surface weeding. In the early growth stage, generally weed 2 to 3 times. Entering August, when the temperature drops somewhat, the shade shed or shade net can be removed to enter a natural growth state.
In the late heading stage of lettuce, soft rot and head splitting often occur. Soft rot is mainly caused by excessively high temperature inside the head. Therefore, the shade shed should not be removed too early. It is more suitable to remove the shade shed when the daily average temperature drops below 20°C. Head splitting is mainly caused by excessive soil moisture, so watering should be controlled in the later growth stage. In addition, to prevent soft rot, it is best not to use human excrement and urine as topdressing.
Summer lettuce heads are generally relatively small and should be harvested in time. If harvested late, the heads will not only grow larger, but will instead become looser and looser, reducing quality. Harvesting is generally done in the early morning to prevent the leaves from wilting.
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