The reason why summer vegetables cause leggy seedlings is mainly due to lack of light and high temperature, especially when the nighttime temperature is too high and breathing is more likely to happen. In addition, nitrogen fertilizer and excessive water, sowing too dense, not timely transfer seedlings, etc., can also easily lead to seedlings leggy. Appearance may occur during summer vegetable cultivation, but the causes of leggy vary from period to period: 1 The most likely cause of leggy, and the period of serious damage is from the emergence to the cotyledon development period, when the leggy was mainly due to sowing Closely after the emergence of the seedlings, the cover was not removed in time, making the seedlings too crowded. 2 After the emergence of the seedlings, the temperature did not cool down in time, and the seedling's epicotyls were also prone to overgrowth. 3 Cotyledons spread to the 2-3 leaf stage. The seedlings did not reach the time of the seedlings, or because the temperature was too high and they were not planted in time (moving seedlings into the grasshoppers), the seedlings became overcrowded and appeared to be long. 4 After planting seedlings until after planting, due to continuous rain, the soil and air humidity in the seedbed is too high, nitrogen fertilizer in the nutrient soil is high, and the management of the seedlings that cannot be ventilated, light and crowded in a timely manner can also lead to leggy. The main methods for preventing seedlings from being leggy are: 1 The planting density should not be too large so as to avoid seedling crowding after emergence. Such as eggplant vegetables generally acres of field need to seedbed 2-3 square meters, broadcast 15-25 grams of seeds. At the same time, ground cover was removed in time after about 30% emergence. 2 and time seedlings, planting and colonization. After emergence, Solanaceae should be treated with time seedlings. Usually, the seedlings should be 2-3 times. When the seedlings are "two leaves and one heart," they should be planted. The density of the transplanted plants is controlled at 120-130 plants per square meter. 3 strengthen ventilation and light, control of temperature and humidity. After exhumation of the seedlings and pre-implantation, ventilation and light transmission should be carried out, and the temperature and humidity should be reduced, and the cold temperature should be exercised to control the overgrowth of the seedlings. 4 Rationalize fertilizer and water management. In the preparation of nutritious soil, attention should be paid to the use of phosphorus and potash fertilizers, and the amount of nitrogen fertilizer should be controlled. Strict control of moisture and topdressing in the seedbed requires topdressing nitrogen fertilizer when dressing is required. 5 Timely sparse seedlings. About 20 days before the planting of eggplant and melon, the over-crowding of the seedlings often occurs. At this time, the seedlings should be properly moved to separate the seedlings and the survival space of the individual plants. 6 drug control apprentice. In addition to the above-mentioned measures, the seedlings can be sprayed with 0.2% Bordeaux (equal) spray or 50% chlorcholine 2000-2500 times.
