1. Timing: the northern region tends to sow in late april to early september, with different varieties being selected for planting in different months. 2. Technical highlights: seeds need to be soaked with cold water, before seeding should be based on soil laxation, fertilization, preservation and whole-scale fertilisation of water-preserving plots, sowing can be smoothly soaked or broadcast, and then the soil can be suppressed and watered, followed by temperature and water management, with multiple pursuits of fertilizer, which should be dominated by nitrogen。
I. Timing of vegetable growing
1. The northern regions generally seed from late april to early september, and harvests from late may to early october, with long-term births of 30 to 60 days。
2. Generally speaking, from late february to late march, varieties such as pre-cooked and cold-resistant red leaf and red leaf should be chosen。
During the period between march and early april and late may, various varieties such as red thongs, red robes, white thongs and willows should be chosen。
In april, between early june and early august, plants should choose the heat-resistant varieties of white, willow and red。
Ii. Elements of the technique for growing vegetables
1. Leaching seedlings
Vegetable seeds are immersed in cold water for 24 hours and are washed several times in order to absorb water. In winter and early spring, immersed seeds will be extracted, washed with fresh water, purified with asphalt, covered with well-ventilated gauze, covered with wet towels, sprung at 15-20°c and seeded when 30 to 50% of the seeds are white. Other seasons are cultivated by direct sowing。
2. Fertilizing the whole area
Vegetable cultivation should select plots with small weeds, which are less stringent for soil, but should preferably be soil laxation, fertility, and water-preserving soils, and bellows prefer alkaline soils with 5,000 kg of decomposed organic fattening per acre, 25% of mixed fattening of 50 kg, precision farming, and a field width of 1 to 1. 2 m。
3. Sowing methods
Vegetable seeds are small, and sowing with some cosmopolitan or fine soil can evenly sow at 0. 25 ~5 kg per acre. It can be spread flatly or on strips, and can be spread on four-legged stripes or uncoolly, and in the spring it can be drenched, lightened in the summer, light in the ground, then suppressed, so that water can be poured out, waiting for the seedling. In winter and early spring, weaning with thin-covered paddy straw and a layer of membranes. In summer, sunscreen is added。
4. Temperature management
In winter and early spring, shells are lifted and re-covered, watered, and small arch sheds are built in the sheds in order to protect the temperature, adding a layer of straw curtains to the sheds at a low external temperature. After the summer season, sunnets are installed in time for early and late exposure。
5. Water management
In winter and early spring, veggies often keep the soil wet and watery, choosing to water as much as possible in the morning of the sun, with a seedling of 0. 2% urea solution, followed by a run for 7-10 days to promote growth. Water is increased in the summer, as appropriate, usually in the morning and evening。
6. Reasonable pursuit of fat
Vegetables need to be followed many times, usually for the first time when the seedling has two real leaves, for the second time after 10-12 days, and once for every harvest. Fertilizers are mainly nitrogen-based, with a thin human urine of 1,500 to 2,000 kg per acre and 5 to 10 kg of urea。
