Seedling Management of Cultivated Cantaloupe

The management of ① temperature requires a higher temperature (25-30 ℃) before unearthing. When 70%-80% of the seedlings are unearthed, the temperature will drop to 20-25 ℃ during the day and 15 ℃ at night, because the Hypocotyl grows fastest during this period from seedling unearthed to cotyledon spreading, which is the most easy stage for seedlings to grow, so special attention should be paid to temperature control to prevent melon seedlings from growing. After the first true leaf unfolds, the seedlings are not easy to grow, so the bed temperature should be raised to about 30 ℃ again, and the lowest temperature at night is 15 ℃. After two true leaves of the seedlings, the bed temperature should be gradually reduced, so that the temperature in the bed should gradually approach the external temperature, and exercise should be carried out before planting. In addition, raising seedlings with large temperature difference between day and night is an effective measure to cultivate strong seedlings. When the true leaves of the seedlings appeared, the temperature in the bed during the day was about 30 ℃, and the night temperature was not less than 15 ℃, which was beneficial to the growth of roots, inhibition of respiration and growth of aboveground parts, and conducive to the cultivation of strong seedlings.

In order to meet the above temperature requirements in the cold season, attention should be paid to the following management: to ensure that more sunlight enters the seedbed so as to increase the bed temperature. For example, uncover the opaque mulch in time and keep the film clean on the seedling bed; cover the grass strictly at night to keep the bed temperature and not ventilated; once the buds begin to arch the soil, remove the mulch immediately; ventilation and ventilation are the main measures to adjust the temperature and humidity in the bed, which should be flexibly mastered according to the growth of melon seedlings and weather conditions. When encountering disastrous weather, we should pay special attention to the local weather forecast, do a good job in preventing cold in time, and take appropriate heating measures. When Shaw has several consecutive days of low temperature, overcast and rainy (snow) weather, special attention should be paid to uncovering the grass and improving the temperature and light conditions. 0.1%-0.3% glucose solution can be used to spray the leaf surface to replenish nutrition. As long as there is no rain or snow during the day, it is necessary to uncover the grass so that there is a certain amount of scattered light in the seedbed; when the sun comes out between rain and snow, seize the opportunity to open a small mouth for ventilation. On the first sunny day after a continuous cloudy day, the seedlings are prone to wilting or paralyzation. in this regard, we should immediately cover the grass to cover the shade, or take the method of covering when the grass is covered, and remove all the grass when the melon seedlings return to normal.

Temperature management of seedling bed in hot season: high temperature in summer makes seedlings susceptible to virus disease, so there must be sunshade facilities on the seedbed to reduce the temperature, cover the sunny day, morning and evening, not cover during the day, not cover at night, let the seedlings see more direct light before and after planting to prevent overgrowth.

② Water and Fertilizer Management Water requirement of muskmelon at seedling stage is very small, and generally no more water is irrigated after sufficient bottom water before sowing. In addition, irrigation will cause the decrease of soil temperature, lead to poor root development, slow seedling growth, low temperature and high humidity microclimate, and induce quenching disease. When it is really necessary to irrigate, choose small water to irrigate in the morning on a sunny day, and avoid flooding. Attention should be paid to reducing the air humidity of the seedling bed, especially in long-term overcast and rainy days, and ventilation should also be maintained; in summer, the seedling water evaporates quickly, the seedling bed should not be too dry, and a small amount of water can be sprayed when the seedlings are short of water. After the seedlings are unearthed, watering should be strictly controlled and the seedlings should be controlled by water to prevent the seedlings from overgrowing. The melon seedlings were treated with water control to properly inhibit the growth and enhance the stress resistance of the seedlings so as to adapt to the climatic conditions after planting.

Topdressing is generally not needed at seedling stage, because before sowing and emergence to 2 cotyledons, it basically depends on the nutrients stored in cotyledons, and then the root system has a strong absorption capacity. In general, as long as the nutrient soil distribution ratio is reasonable, it will not be a problem to maintain up to 3-4 true leaves. If the melon seedlings are thin in the later stage and the leaves are light and show symptoms of lack of fertilizer, 0.2%-0.3% urea and potassium dihydrogen phosphate can be used as foliar root topdressing.

The common diseases in ③ seedling stage are catchment, and the common pests are gourd and ground tiger. The identification and control methods can be referred to the part of pest control.

The cultivated seedlings meet the following criteria: among the 4 true leaves of 30-35 days old, the height of large seedlings is less than 10 cm, the Hypocotyl is stout, the cotyledon node is no more than 3 cm above ground, the cotyledon is intact, the true leaf leaf is thick, dark green, free of disease spots and insect pests, the nutrient soil block is complete, the root system is well developed, the main root and lateral root are strong, and the aboveground and underground parts are not damaged.