What about the rotten roots of spring cabbage at seedling stage?

Cabbage is a very old vegetable, and people began to make them into delicious dishes more than 4,000 years ago in ancient Greek and Roman times. In Europe today, wild cabbage can still be seen growing on barren, cold, chalky, grassy beaches. Brassica oleracea L. Cruciferae brassica for the annual or biennial herbs, is one of our important vegetables. All varieties of cabbage originated from the Mediterranean Sea to the North Sea coast except Chinese cabbage. It was cultivated by the ancient Romans and Greeks as early as 4,000 - 4,500 years ago.

Growing Environment of Cabbage

Cabbage likes mild, moist, and plenty of light. It is cold resistant and has the ability to adapt to high temperatures. The optimum temperature for growth is 15-20℃. Fleshy stem expansion stage such as the case of high temperature above 30℃ meat easily fibrosis. The choice of soil is not very strict, but suitable for humus-rich clay loam or sandy loam planting. Cabbage seedlings must undergo vernalization at 0-10℃, then bolting, flowering and fruiting under long days and appropriate temperature.

What about the rotten roots of spring cabbage seedlings?

Spring cabbage seedling stage is mostly in the winter of low temperature and lack of light, easy to appear various physiological obstacles or diseases. Although the temperature in winter this year is higher than in previous years, there are many foggy days. Due to the high humidity and weak light, it is unfavorable for cabbage growth. The recent root rot of cabbage seedlings is mainly due to the following reasons:

Root hypoxia low temperature high humidity weather water evaporation slow, if the seedbed watering more, and can not evaporate in time, will cause insufficient oxygen in the soil, resulting in the root system can not carry out normal respiration, and then cause rotten roots. There is less rain and snow in winter this year, but cloudy days and foggy days last for a long time, resulting in high humidity in seedling beds and easy to rot roots.

Black stem disease of cabbage seedlings infected with black stem disease appeared gray patches on cotyledons and true leaves, and there were long purple-black spots on the proximal stem, slightly depressed, which could spread to the roots. When seriously ill, all fibrous roots rot and plants wither and die. Black stem pathogen spread with water flow, high temperature (25℃) and high humidity conditions easy to occur. Nursery beds in sunny days if ventilation is not timely, will cause disease epidemic, leading to rotten roots.

After cabbage black rot infection, the cotyledons appear water-soaked spots with black necrosis. When the disease spreads in high temperature and humidity, the edges of leaves or veins form "V"-shaped chloasma, and the veins are necrotic by small black spots or stripes. Pathogen along the veins and petioles to expand, vascular blackened, can develop to stem and roots. Due to black rot infection, it can also cause root rot. The soil of seedling bed, such as cabbage planted in previous crop, will aggravate the occurrence of black rot.

Spring cabbage seedling root rot response measures:

In view of the above reasons, disease-free bed soil should be prepared before seedling raising. It is best to disinfect the bed soil in advance. It can be sprayed with formalin solution and sealed for 15~20 days. After opening, the smell will dissipate before sowing. When sowing, cover the ground with carbendazim to avoid infection of germs as much as possible. Pay attention to ventilation during seedling period after sowing, keep 15℃~20℃ in daytime and 8℃~10℃ at night, and the temperature should not be too high. In cloudy, rainy and snowy days, the temperature and humidity management of seedling beds should be strengthened, especially the moisture discharge. If the seedbed is too wet, but the temperature cannot be ventilated for a long time due to low temperature, plant ash can also be scattered in the seedbed to absorb moisture. Seedbed watering should be controlled. Sunbed seedlings are generally watered only when sowing, sub-seedlings and seedlings are raised. The rest of the time is generally not watered. Greenhouse and hotbed watering also depends on the weather. Choose several consecutive sunny days. Seedbed as far as possible to maintain sufficient light, overcast snow days should also ensure that seedbed see scattered light.