Lesser Cold does a good job in the seedling management of early spring stubble in season.

January 5th is Lesser Cold's solar term, around the "39 th Day", marking the beginning of the coldest day of the year. At this time, the average temperature in Beijing is about-5 ℃, the extreme minimum temperature is below-15 ℃, and there are more than haze days, which is the shortest time of sunshine, the lowest temperature and the changeable weather in a year. It is the critical period of raising seedlings of temperature-loving vegetables such as chili, eggplant, tomato and melons in greenhouse and greenhouse in early spring, and it is also the key period of overwintering vegetable management in greenhouse.

? Seedling raising and management of crops in early spring

It is very important to cultivate strong seedlings of the right age, which is the basis of high quality and high yield. as the saying goes, "half of the seedlings are strong". During this period, the temperature is low, the light is weak, and the sunshine time is short, so heating, heat preservation and increasing light are the key to the success or failure of seedling cultivation. In the seedling shed, the solar greenhouse with good lighting conditions and good heat preservation effect should be selected, and the hot line should be laid before raising seedlings, and supplementary lights can be installed if possible.

Raising seedlings of ◆ melons and eggplant fruits and vegetables in spring greenhouse cucumber and zucchini in greenhouse in early spring and temperature-loving crops such as tomato, eggplant and pepper planted in spring greenhouse began to grow seedlings. Cucumber, tomato and eggplant should be grafted as far as possible, which can enhance cold resistance, disease resistance and stress resistance, and have the effect of nematode resistance. General tomato seedling age 50-60 days, eggplant 60-70 days, cucumber 40-50 days. Tomato and eggplant seedlings were raised with 50 or 72 holes, cucumbers were raised with 32 or 50 points, or 8 × 8 cm nutrition bowl was used to raise seedlings. Choose the seedling substrate with good brand quality, or use 2: 1 ratio of peat nutrient soil and vermiculite to prepare the substrate, adding 10 kg N, P and K ternary compound fertilizer per cubic meter. Do a good job of seed soaking and chemical treatment, choose sunny days to sow seeds, so that the sowing is uniform and the thickness of the soil cover is the same.

Seedling raising of ◆ cabbage and lettuce in early spring, the best seedling period for cauliflower, cabbage, lettuce, lettuce and other crops cultivated with plastic film mulching in early spring was in the middle of January. The seedlings were raised by plastic pot with 72 or 128holes, and the varieties such as "Zhonggan 21" with early maturity and good quality were selected to sun up one day in advance and sow evenly after pouring enough moisture. Remember that the night temperature of cabbage seedlings should not be lower than 12 ℃ for a long time, so as to avoid early bolting through the vernalization stage.

Management of ◆ bred seedlings in early spring greenhouse tomato, pepper, eggplant and other eggplant crops and cabbage, celery, lettuce, etc. are growing seedlings, which is an important period of management. first of all, it is necessary to keep warm and see more light, turn on the supplementary light on continuous cloudy days, and replenish the light for about 12 hours a day. We should also pay attention to that the night temperature should not be too low, and the lowest temperature should be above 13 ℃, otherwise the long-term low temperature will affect the flower bud differentiation, form abnormal fruit, and directly affect the fruit quality and yield in the future. The common nursery bed seedling method divides the seedlings in time at the 2-leaf stage, and at the same time, it is necessary to do a good job in the prevention and control of diseases at the seedling stage. Recently, moles are harmed in many sheds, which should be controlled by means of rat racks and other means.

? Harvest and seedling pulling of crops in autumn and winter in solar greenhouse

Temperature-loving crops such as tomato, cucumber, pepper, zucchini and eggplant in autumn and winter have entered the late growth stage. Whether to pull seedlings or not is decided according to the plant growth and the temperature in the greenhouse. If the lowest indoor temperature at night is above 13 ℃, the seedling pulling will be postponed as far as possible. If you do not meet the above conditions, you should timely pull seedlings, and pay close attention to stubble soil preparation, ready to sow or plant cold-tolerant rapeseed, lettuce and other fast-ripening vegetables.

? Key period of management of temperature-loving vegetables in overwintering stubble

At present, it is the key period for the management of temperature-loving vegetables in tomato and cucumber overwintering crops. Pay attention to weather changes to prevent strong cold spell and continuous cloudy weather from causing damage to crops, and temporary heating measures such as Yuba, heating combustion blocks or electric blast furnaces should be taken if necessary. The greenhouse film should be scrubbed frequently to enhance the light transmittance; timely pruning and pruning and pinching of fallen vines, auxiliary pollination, and thinning of excess buds and fruits; scientific watering and topdressing, and topdressing should be followed by drip irrigation with comprehensive nutrition and reasonable proportion of "Christmas tree" equal-speed soluble fertilizer, or nitrogen, phosphorus and potassium alginic acid or humic acid organic liquid fertilizer. Set up cisterns, tanks or buckets in the greenhouse, wait for the water temperature to rise before watering, but also pay attention to small water frequently watering, winter greenhouse vegetables should avoid flood irrigation, in order to prevent the sudden drop of ground temperature and affect the growth of roots and the ability to absorb water and nutrients.

? Transplanting and sowing of cold-tolerant and fast-ripening vegetables in greenhouse

Fast-ripening vegetables such as rape, chrysanthemum, spinach, lettuce, Chinese cabbage and cherry radish planted in solar greenhouse are the season for sowing and planting. To apply fully mature, fine broken organic fertilizer 1500-2000 kg, fine soil preparation, so that the ground is flat, the border is flat, the ridge is straight, and the surface soil is loose without light and dark. Chrysanthemum chrysanthemum, spinach, cherry radish and pakchoi should be planted directly, sowing evenly after pouring enough moisture, covering the soil thin and thick, and covering a layer of plastic film after sowing, which can play the role of heat preservation and moisture preservation, and be removed in time when 50% of the seedlings emerge. Strengthen the management during the growth period and grow fresh and safe products to supply the off-season market in spring.

? Management of special weather

■ removes snow from the front and rear roofs in time when it snows. Avoid melting snow on grass or heat preservation quilt to reduce its heat preservation effect. After the snow stops and when it is cloudy, under the premise of ensuring the temperature in the greenhouse above 12 ℃, the grass can be opened around noon to make the crops receive 2 hours of scattered light; in case of long overcast and sudden sunny weather, the grass grass should be beaten apart, or the heat preservation should be rolled up half, in case the sun is too strong to cause plant wilting; in snow and cloudy days can not carry out topdressing, watering, pruning, fruit thinning and other agricultural operations. For some greenhouses with large span and poor skeleton firmness, the scaffolding should be supported and strengthened in time to prevent the greenhouse from collapsing when it snows.

■ extreme cold weather in order to ensure the safe production of temperature-loving vegetables, temporary heating measures can be taken, such as installing Yuba heat conversion light bulb, air heating hotline, electric blast furnace, heating combustion block and oil-fired hot air stove, etc., to avoid indoor temperature too low and affect crop growth and the formation of freezing injury.

■ continuous cloudy days and haze continuous overcast days and haze weather will have a great adverse impact on the environment of the solar greenhouse, which can easily lead to the weakening of light, the decrease of temperature and the increase of humidity in the greenhouse, while weak light, low temperature and low humidity are also one of the main reasons for the high incidence of vegetable diseases and insect pests in greenhouse. Therefore, taking measures such as light supplement, dehumidification and heating in continuous cloudy days or haze weather is an important link to ensure the healthy growth of greenhouse vegetables in winter.