The lowest germination temperature of rotten leafy vegetable seeds is 0°C~4°C. Under normal circumstances, seedlings will not emerge after 7 days of sowing, indicating that the seeds have been rotted. Preventive measures: Select the sunny and warm weather sowing, using electric hotbed or brewing hotbed nursery, thickening cover, etc., to increase seedbed temperature, in order to facilitate seed germination. The formation of a hat seedling and a hat seedling is when the cotyledon is unearthed, the belt is taken out of the soil and is worn on the top of the cotyledon like a hat, which affects the normal development and photosynthesis of the cotyledon. The reason is that bed soil is too dry and the soil is too thin. Preventive measures: seedbed bottom water to be poured, the thickness of the cover soil should be appropriate, the general small seed cover soil thickness of 1 to 1.5 cm, medium grain seed 1.5 to 2 cm, large seeds 3 to 4 cm, sowing until emergence, the bed cover film, Keep the soil moist. Roots of cold roots, roots and roots of burned roots and roots of burned roots are due to the low temperature of the bed soil and high humidity. The performance of the roots is yellowing and wilting of the leaves, and the seedlings stop growing. Nursery bed soil organic fertilizer and bed to soil ratio is generally 1? 1, the application of organic fertilizer without decomposition or excessive fertilization, prone to burn phenomenon. Preventive measures: to prevent cold roots, roots can be managed to improve the seedbed temperature, reduce the amount of water, cultivating loose soil, ventilation and reduce humidity. Once root burning occurs, water can be poured into the pot to reduce the concentration of fertilizer while ventilating and dehumidifying. The formation of aging seedlings aging, the general performance of seedlings with small stems, roots aging is not easy to regenerate new roots, leaves small and thick, dark green color, such seedlings commonly known as "small old seedlings." Aging seedlings are caused by seedlings or seedlings that are too long, slow seedlings after planting, low yield, and prone to premature aging. Preventive measures: Strictly control the age of seedlings, and the length of seedlings should be appropriate; seedlings should preferably adopt the method of controlling temperature without controlling water. The time of seedlings should not be too long at low temperature to prevent seedling ageing caused by prolonged drought; spraying 1010 on seedlings of aging seedlings. - 6 to 3010-6 gibberellin plus 500-fold glutinous liquid fertilizer, or 300-500 times potassium dihydrogen phosphate solution to stimulate seedling growth. The main reasons for the formation of fossilized seedlings leading to seedling rigidity are as follows: First, the early spring is cold, the seedbed temperature is low, and the roots develop slowly; secondly, in the late stage of nursery, in order to restrain the seedlings from being long and use less water or water, the result is due to drought. The root development of the seedlings was severely affected. Preventive measures: The seedbed temperature should be raised as early as possible to prevent the seedlings from growing at low temperatures for long periods of time. To ensure moisture supply, timely ventilation after watering. If the seedlings grow late in the nursery, the seedbed temperature should be reduced, the light intensity and light time should be increased, the ventilation should be increased, and no watering or watering methods should be used to control seedling growth. Seedlings of leggy seedlings are generally characterized by thin stems, long internodes, thin leaves, and light color. The leggy seedlings have weak resistance and low survival rate after planting, and they are slow to slow seedlings and cannot obtain early maturation and high yield. The main cause of leggy seedlings is high temperature and high humidity. Insufficient light can also lead to leggy seedlings. Preventive measures: First, according to the temperature requirements of seedlings, timely ventilation, especially the night temperature should be appropriately reduced; Second, to ensure that the transparent cover clean, increase the light intensity and light time as much as possible, to promote the healthy growth of seedlings; Seedlings of fast-growing, easy-to-live roots should be seeded in a timely manner to prevent over-crowding of the seedlings. Also, attention should be given to the combined use of nitrogen, phosphorus, and potassium, or to plant growth regulators. Freezing damage and cold damage are damages to the plants when the ambient temperature is below 0°C. Freezing damage is often devastating. Chilling injury refers to the fact that the environment temperature is lower than the minimum temperature that the plant can tolerate without freezing, and the growth and development of seedlings are hindered and severely unable to recover. Preventive measures: the use of coal stove heating room, plumbing heating, etc.; using multi-layer covering insulation, such as covering the film, deducting a small shed, cover straw, etc.; strengthen the ventilation and hardening of seedlings, and in the seedbed increased phosphorus and potassium fertilizers, improve Seedlings cold-tolerant; intertillage to enhance soil heat absorption capacity. Super Absorbent Bath Mat,Bath Mat,Diatomite Health Hot Bath Mat,Non Slip Bath Mat Dongguan Vanilla Bioengineering Co., Ltd. , https://www.healthecigarette.de