Tomato plant leggy mainly due to soil moisture, relative humidity of about 80%, more nitrogen fertilizer, or continuous rainy weather, air humidity is often higher than 50% -60%, lack of light, colonization too dense, or poor ventilation and ventilation. The temperature of autumn tomatoes is too high, nitrogen fertilizer is too high, and the lack of timely planting is also easy. Preventive measures: 1. Control seedling age and timely planting. Strict control of seedling age, such as - precocious tomato seedlings about the age of 60 days, mid-late maturing varieties should be 70-80 days, autumn tomato seedlings about 25 days. 2. Early preparation for planting, promote seedlings and seedlings. 10-30 days before planting, do a good job in soil preparation, basal fertilization, covering the top film and skirt of the greenhouse, drainage around the shed, etc., so that when the larvae are planted, the humidity in the shed is lower and the temperature is higher, which is conducive to easing seedlings. 3. Control the amount of nitrogen fertilizer, using deep sorghum cultivation to promote root growth. 4. timely and appropriate amount of pruning leaves, scaffolding, so that ventilation and good ventilation, and the use of growth regulators such as anti-dropping flower spray, promote fruit set, inhibit excessive vegetative growth. 5. The administration of the medicament. After planting seedlings, shoots were sprayed every 15 days with equal volume of Bordeaux mixture or 77% of WP 500-700. 6. Ventilate in time. After the plants are rejuvenated, under a constant temperature, they must ventilate and reduce the humidity in the greenhouse. - If you begin to flower and bear fruit, you must put a bottom wind under the skirt. When the outside temperature is not lower than 15°C at night, it should be ventilated overnight. Into the hot summer season, the plastic film can be removed, as in open field cultivation. 7. Control the fertilizer. Bottom fertilizer is sufficient, generally do not apply fertilizer before flowering and fruit setting, especially the use of mulching, after sitting on the fruit, it began to appropriate fertilizer according to the situation. JIANGSU CLS TECHNOLOGY CORP.LTD , https://www.js-cls.com