What causes the heart of Chinese cabbage to turn black

The blackening of the heart of Chinese cabbage may be caused by low-temperature frostbite, bacterial soft rot, black spot disease, calcium deficiency, or improper storage. It is necessary to determine the cause based on specific manifestations and take targeted treatment measures.

1. Low temperature frostbite

When Chinese cabbage is exposed to sub zero temperatures, damage to its cell structure can lead to water stained black spots on the core. The frozen area initially appears semi transparent and gradually turns black, soft, and rotten after thawing. Failure to take proper insulation measures during outdoor storage or transportation in winter can easily lead to this situation. Mild frostbite can result in the removal of spoiled parts and consumption of intact leaves.

2. Bacterial soft rot disease

is caused by infection with Erwinia, resulting in a grayish black wet rot and a foul odor in the vegetable heart. Due to mechanical damage or insect bites during harvesting, bacterial invasion can accelerate decay in high temperature and high humidity environments. The diseased plant needs to be discarded as a whole, and nearby cabbage should be sprayed with agricultural streptomycin agents such as mycorrhizal or chloramphenicol to prevent spread.

3. Black spot disease

is a fungal disease caused by Alternaria alternata, which produces circular black brown lesions with yellow halos on the edges of the cabbage. The disease is more severe in continuous cropping plots or rainy seasons, and black mold layers can be seen on the diseased leaves. In the early stages of the disease, fungicides such as mancozeb or azoxystrobin can be used to control it, and in severe cases, the diseased plant needs to be destroyed.

4. Calcium deficiency

insufficient absorption of calcium during growth can lead to black brown dry rot inside the cabbage, commonly known as heart rot disease. Soil acidification, excessive nitrogen fertilizer, or drought can all affect the absorption of calcium. Spraying calcium chloride solution on the leaves can alleviate symptoms, and it is necessary to maintain stable soil pH during planting.

5. Improper storage

After harvesting, if the vegetables are stacked too tightly or the environmental humidity is too high, the heat generated by respiration cannot be dissipated, which can cause anaerobic respiration and lead to black hearts. When storing, the outer protective leaves should be retained and placed in a ventilated and cool place, with a temperature controlled between 0-4 degrees Celsius.

When purchasing Chinese cabbage in daily life, attention should be paid to observing whether the base of the cabbage is fresh, and avoiding purchasing plants with damage or freezing marks. It is recommended to wrap the vegetable hearts in plastic wrap and refrigerate them for home storage, and consume them within two weeks. If slight blackening is found in the vegetable heart, the spoiled part can be removed. If the dark area exceeds one-third or is accompanied by mucus or odor, the whole plant should be discarded. During the planting process, crop rotation is necessary to prevent and control pests in a timely manner. Before harvesting, watering should be controlled to improve storage tolerance.