The Causes of Rotting Roots in Spring Cabbage Seedlings and the Countermeasures
At the same time as Suning Vegetable Farmer Wang is dealing with challenges in cabbage seedling cultivation, local growers are also facing issues related to winter conditions that are affecting plant health. Cabbage seedlings are often exposed to low temperatures and frost during the winter months, making them vulnerable to various physiological problems and diseases. Although this year’s winter has been slightly warmer than previous years, it has been more foggy, leading to high humidity and weak light—conditions that are not ideal for healthy cabbage growth. Recently, some farmers have reported rotting in their cabbage seedlings, and there are several key reasons behind this issue. One of the main causes is the combination of low temperature, high humidity, and poor air circulation. Under such conditions, moisture evaporates slowly, and if the seedbed is overwatered without proper drainage, the soil can become waterlogged, leading to a lack of oxygen. This suffocation of the roots prevents them from breathing properly, which ultimately leads to root rot. This year, although there has been less snow and rain, the prolonged periods of fog and cloudiness have increased humidity levels, creating an environment conducive to disease development. Another common problem is black stem disease, which affects both the cotyledons and true leaves of cabbage plants. Symptoms include small black spots on the stems, along with long purple-black lesions near the base of the plant. These lesions may spread to the roots, causing the fibrous roots to rot and the plants to wilt and die. The black stem pathogen spreads through water, and it thrives in warm (around 25°C) and humid conditions. If the seedlings are not well-ventilated on sunny days, the disease can quickly spread and cause severe damage. Cabbage black rot is another serious issue. It begins with water-soaked lesions on the cotyledons, followed by black necrosis. Under high temperature and humidity, the disease spreads rapidly, forming a "V"-shaped lesion along the leaf edges or veins, with small black spots appearing on the vascular tissue. The pathogen moves through the veins and petioles, turning the vascular bundles black and potentially spreading to the stems and roots. Black rot bacteria can also cause rot in the soil, especially when conditions are favorable for their growth. To prevent these issues, it is essential to prepare clean, disinfected soil before planting. One effective method is to spray the soil with formalin solution and then seal it for 15 to 20 days. After the odor dissipates, the soil can be used for sowing. Before planting, it is advisable to cover the ground with carbendazim to reduce the risk of infection. During the seedling stage, good ventilation is crucial. The daytime temperature should be maintained between 15°C and 20°C, while the nighttime temperature should stay between 8°C and 10°C. Avoid keeping the temperature too high, especially on cloudy or rainy days. On days with continuous cloud cover or snow, it's important to manage both temperature and humidity carefully. If the seedbed becomes too wet, avoid prolonged ventilation due to the low temperatures. Instead, consider sprinkling wood ash to help absorb excess moisture. Watering should be controlled, and seedlings are typically only watered at specific stages: during seeding, transplanting, and seedling growth. In most cases, watering is avoided otherwise. Greenhouses and hotbeds should follow similar guidelines, with watering done only after several days of sunshine. Ensuring maximum light exposure is also important, and on cloudy or snowy days, scattered light should be provided to support healthy growth. Shandong Changchongyun Intelligent Technology Co., Ltd. , https://www.ccyparking.com