Rape planting technique: how to grow it in greenhouse? When is the best time to sow seeds?

Rape is a pointed leaf lettuce with tender shoots and leaves as its products. it tastes delicate and is deeply loved by the public, so what are the planting techniques of rape? How to grow in a greenhouse? When is the best time to sow seeds?

First, the growth habits of rape.

The condition of rape seed germination is not high, generally, it can germinate smoothly when the temperature is above 4 ℃. If the temperature is between 15-20 ℃, it only takes 3-4 days for rape seeds to germinate. If the temperature exceeds 30 ℃, rape seeds will not germinate. The most suitable temperature for rape seedling stage is 12-20 ℃. If the temperature exceeds 24 ℃ during the day and 19 ℃ at night, it is easy to cause immature bolting of rape.

Second, what are the planting techniques of rape in greenhouse? When will the seeds be sown?

1. Sowing time

The main results are as follows: (1) Seedling is raised in the greenhouse from January to March in spring sowing, 2 rows are built in the standard greenhouse, a ditch is opened in the middle, the bed is deeply turned over, the bottom water is watered, the seeds are sown in the border, the seeds are covered with mud, and the plastic film is spread to cover the seeds. Generally, the seedlings will emerge in 10-15 days, and the seedlings will emerge longer in rainy and cold time. Remove the plastic film after the seedlings, ventilate and ventilate, prevent high temperature injury during the day and frost injury at night.

(2) to raise seedlings in open field during summer sowing from April to June, select high potential land, 2 meters continuous ditch, deeply apply rotten stable fertilizer, and build beds and leveling. Soak the seeds for 3 hours, wait for the seeds to dry before sowing. Pour enough bottom water on the seedling bed, spread the seeds on the border surface, cover the seed mud, pour enough water, in case of high temperature and drought, cover the border with sunshade net, uncover the net sooner or later after finishing the seedlings, the fertilizer and water of the seedling bed should be moderate and should not be too dry.

(3) sowing seedlings in the shed from July to September in autumn, rape seedlings should be soaked to promote germination. The method is to wrap the seeds in gauze and soak them in water for 3 hours for 4 hours, then take them out and put them in the refrigerator for 10 hours and 15 hours, and 75% of the seeds can be sprouted. Autumn sowing seedlings had better use a small arch shed or greenhouse, pay attention to soil moisture after emergence, should not be too dry and wet and pull out weeds in time to ensure smooth drainage.

2. Seedling stage management

The seedlings of Brassica napus produced two true leaves, and the transplanting density was 6 × 6 cm. Rape seedbed should be kept moist and sunshaded at noon. At the same time, rape should pay attention to pest control at seedling stage.

3. Prepare the land and make beds.

Before planting rapeseed, 3500-4000 kg of rotten organic fertilizer, 20-25 kg of phosphate fertilizer, 40-50 kg of nitrogen fertilizer, 10-15 kg of potash fertilizer, 1 × 10-1.5 m of border width, 10 × 10-15 cm of plant spacing and 40-50,000 plants per mu were applied.

4. Ploughing and weeding

After planting slow seedlings of rape, apply a small amount of available nitrogen fertilizer for 1 to 2 times combined with watering, generally applying urea or ammonium sulfate 5 kg per mu, in order to promote the growth and growth of the plant, and always keep the soil moist and weed control in time.

5. buckle the shed at the right time

Rape is a fast-growing leafy vegetable, and the suitable growth temperature is 18-25 ℃. When the night temperature is lower than 12 ℃, the shed should be buckled. After buckling the shed, the temperature and relative humidity in the greenhouse should be adjusted in time. Generally, the relative temperature in the greenhouse should be less than 90%.

6. Reasonable topdressing

Rape cultivation should be kept clean and hygienic, and 0.3% potassium dihydrogen phosphate and urea solution should be used for foliar spraying for 3 times in the early and middle stages of growth. During the whole growing period, topdressing 2-3 times, applying 5-10 kg of urea or 10 kg of ammonium sulfate per mu.

7. Disease and pest control

The pests of rape are mainly aphids, which can be sprayed with 40% dimethoate EC 800 times. The main diseases are downy mildew and soft rot, which are controlled by 300 × 500 times of 70% mancozeb wettable powder and 0.02% agricultural streptomycin spray respectively.

8. Timely harvest

When the number of leaves of rape reaches 3034, the plant height is 45cm, and the degree of expansion is 60cm, it can be harvested at a time of 2cm to 3cm from the ground. after harvest, the old and diseased leaves can be removed and supplied to the winter market in time.

This is a good time to grow rape and wheat in the greenhouse. Farmers with ideas should seize the time.