How to grow onions?

Onion planting can be carried out by direct seeding or seedling transplantation. Generally speaking, if it is planted in a large area and direct seeding is adopted, the sowing time should be sooner rather than later. When the ground temperature of 10 cm soil layer is stable at 5℃, sowing can be done. Let's learn onion planting techniques together.

First, sow and raise seedlings.

1, sowing date

Because onions are sensitive to temperature and sunlight, it is very important to choose sowing date, that is, to cultivate strong seedlings and prevent them from growing too much before winter. After vernalization, early bolting appeared in the second spring, because onion belongs to green vernalization variety. When the seedlings grow to a certain size, the diameter of the onion is generally above 0.8 cm.

2, seedbed preparation

Choose neutral soil with loose and fertile soil, strong water and fertilizer conservation ability and convenient irrigation and drainage. Select the plot that has not been planted with onion and garlic for 2-3 years as the seedbed. Combined with soil preparation, it is suggested that 4000 kg of organic fertilizer, 2000 kg of chicken manure, 25-30 kg of diammonium phosphate and 7- 10 kg of potassium sulfate should be applied per mu, or biological phosphorus and potassium fertilizer should be used. After raking, the soil must be raked into small pieces and leveled. Pay attention to the amount of seeds.

Step 3 disinfect the bed soil

Generally speaking, carbendazim and 50% thiram are mixed according to the ratio of 1: 1, then the mixed powder and fine dry soil are evenly mixed, spread on the bed surface, and then ditched.

4. Seed treatment

Dry-mix the seeds with the mixed powder, and the dosage is 0.3% of the weight of the seeds.

5, the method of sowing

You can sow seeds or drill holes.

Drill sowing: Digging ditches in the seedbed, with the ditch depth of 1.5 ~ 2 cm. Sweep and cover the soil with a broom after sowing. Then step on the sowing ditch with your feet. In order to ensure the orderly emergence of seedlings, it is necessary to ensure sufficient water. If the seedbed soil is dry before sowing, water 1 ~ 2 before sowing. Sowing: firstly, water is poured on the seedbed, and then a thin layer of fine soil is spread after the water permeates, then sowing is carried out, and finally the soil is covered with a thickness of 1.5cm. 6. Seedbed management

Keep the seedbed moist after sowing to prevent soil hardening from affecting seedling emergence. Proper water control can only be carried out after the seedlings grow the first true leaf. When the young stem grows to 4 ~ 6 cm, it will be arched. This stage is called. Bow? . From the appearance of cotyledons to the straightening of embryonic stems, this stage is called? Stretch? . Usually, the bottom water is poured before sowing, and it is generally not watered after sowing until? Bow? When watering, the whole seedling can be guaranteed. If you don't water before sowing, or don't water at all, it is recommended to water 2 ~ 3 times after sowing until the seedlings are unearthed.

Water and fertilizer management: To ensure sufficient soil moisture at the bottom of the seedbed, spray water 1 time in time after sowing to connect the upper and lower water, and then water after uncovering the film after seedling emergence. Expose 60% ~ 80% after watering 1 time. In the future, we should keep the seedbed dry and wet. Before transplanting, a small amount of water should be watered during the seedling hardening period, but water cannot be stopped. When the seedling height is 10 ~ 15 cm, it can be watered according to the seedling situation and applied with appropriate amount of topdressing, or sprayed on the leaves. It is suggested that spraying 0.2% ~ 0.4% potassium dihydrogen phosphate on15 days before transplanting can promote rooting after transplanting.

Temperature management: before emergence after sowing, the daytime temperature should be controlled at 20 ~ 25℃, and the nighttime temperature should be higher than 65438 03℃. After the emergence of onion, the daytime temperature should be 15 ~ 20℃. When the temperature exceeds 28℃, outdoor air should be released to ensure that the night temperature is 10℃ but not lower than 8℃.

7. Select the standard of strong seedlings.

The requirements are 3 ~ 4 leaves, 0.4 ~ 0.5 cm pseudostem, 25 ~ 30 cm plant height, 4 ~ 5 cm onion, fibrous root 13 ~ 15 and seedling age of 45 ~ 55 days.

Second, onion colonization

1, soil preparation and soil preparation

Planting is also to choose loam or sandy loam or black soil with good drainage, flat land, loose and fertile soil and good permeability. Remember that the previous crop should not be onion, garlic or leek, and the pH should be 6.3 ~ 7.8. It is better to apply decomposed organic fertilizer in coordination with soil preparation, which must be decomposed, finely divide organic fertilizer or chicken manure, add diammonium, urea and potassium sulfate, and use 65,438+0 kg of phosphorus activator per mu. It should be deeply plowed and raked, and the soil and fertilizer should be evenly mixed before leveling.

2. Grading the seedlings before transplanting.

Select seedlings with developed roots, strong roots and uniform size for grading. The reference standard is about 15cm in height and 0.8cm in thickness for the first-class seedlings, about 12cm in height and 0.7cm in thickness for the second-class seedlings, and about 10cm in height and 0.6cm in thickness for the third-class seedlings. After grading, planting is easy to manage and can promote consistent growth in the field.

3. The transplant method should be correct

Attention should be paid to watering the seedbed the day before emergence, grading after emergence, root soaking and disinfection, and evenly mixing 600 times solution of phoxim and 600 times solution of carbendazim for disinfection. It is recommended to use a wooden sign jack for transplanting, the depth is about 3 cm, and the wife should not be too deep. Pay attention to the plant spacing and the number of transplanting per mu when transplanting, and the density must be appropriate.

4. Selection of planting time

Autumn transplanting time is suitable for the root system to resume growth after planting, but it is not suitable for the plant to overwinter. If transplanted too early, the plants will start to grow, which will lead to excessive overwintering seedlings and easy bolting in the next year. If it is planted too late, its root system has not resumed growth and is easily affected by freezing injury. It is usually suitable to plant it 30 ~ 40 days before the arrival of severe cold. The planting time is the end of 65438+ 10 or the beginning of 165438+ 10.

Thirdly, field management after planting.

1, do a good job in water management

Onions will enter the slow seedling stage about 20 days after planting, because the temperature is relatively low when planting, so they can't be watered in large quantities. Watering will lower the ground temperature and slow down the growth of seedlings. However, there is no shortage of water, so the need for watering at this stage is getting less and less. The choice is not to let the seedlings wither, the ground is not dry, and let the seedlings take root and survive quickly.

Onion seedlings planted in autumn will enter the wintering period after survival. At this time, it is necessary to ensure that the planted onions can safely overwinter, and to choose the right time to water the overwintering water.

After wintering and turning green, it enters the stem and leaf growth period. At this stage, onion's requirement for water is not only to promote growth, but also to control water to prevent excessive growth. The way to control watering here is what everyone usually says? Squat seedlings? . Under normal circumstances, the squatting time is about 15 days. When it is observed that the outer leaves of onion seedlings are dark green with many waxy layers, the mesophyll thickens and the color of the heart leaves darkens, the squatting seedlings can be ended. After squatting, you can water the seedlings, usually once every 8-9 days. The principle is that the soil is wet and dry alternately, which promotes plant growth and prevents overgrowth. Stop watering 7-8 days before harvesting.

2. Fertilization management of onion

Pay attention to the application of appropriate amount of ammonium sulfate or urea after delayed emergence and before bulb expansion. The dosage of ammonium sulfate per mu is 10 ~ 15 kg, and the dosage of potassium sulfate is 8 kg. Spraying 0.2% ~ 0.3% potassium dihydrogen phosphate on leaves for 3 ~ 4 times and 15 days before harvest is the onion bulb expansion period. Spraying 0.25% fresh green pigment before harvesting can inhibit germination from scratch and prolong storage period.

3. Onion intertillage management

If there is no contrast film, shallow intertillage should be carried out 2 ~ 3 times after slow seedling and before bulb expansion, and the depth should not exceed 3 cm. If it is covered with plastic film, the film should be removed before the high temperature comes, and the normal temperature of bulb expansion period should be 15 ~ 26℃. Sometimes, the film can be covered with 2 cm of soil, which can achieve the purpose of cooling down and prevent the growth of weeds.

4, in addition to the bolt support management

This is mainly for early bolting onions, which should be cut from the lower part of the flower bud before the flower bulb is formed, or separated from the top of the flower bud and torn into two pieces from top to bottom to prevent the consumption of nutrients after flowering, and the lateral buds will not grow to form fuller bulbs. After bolting in advance, the plant can still obtain a certain yield.

Fourth, timely harvest.

After the leaves at the base of onion begin to turn yellow, when its pseudostem slowly loses moisture and becomes soft, it will fall down when it is made. At this time, the bulb stops expanding and the outer scales can be received when they are leathery. Choose sunny days. Be careful not to expose onions to the sun.

The above are the management techniques of onion planting. If you have any questions about onion planting, you can also leave a message in the comment area to discuss onion planting together.