What to do if mint leaves turn black

1. Water Management

The blackening of mint leaves may be due to a problem with the watering method. Generally, when watering mint, you need to follow the principle of watering thoroughly when the soil is dry. Do not water casually if the soil is not dry. Wait until the soil is completely dry and water it thoroughly all at once. It is best to use rice water when watering, which can provide a certain amount of nutrients for the mint. It is also okay to use ordinary clean water, but be careful not to use tap water directly. The tap water needs to be dried in the sun for a while before use.

2. Ventilation and light transmission

Mint prefers light. If there is insufficient light, the leaves will easily turn yellow and black. Therefore, it is best to place it in a place with sufficient sunlight when growing it. If it is grown indoors in a corner without sufficient light, the potted plants need to be placed in a place with sufficient sunlight for one or two days every two or three days, and repeated this process. However, it should be noted that in summer, it is necessary to avoid direct sunlight exposure and appropriate shading treatment is required.

3. Treatment of the cause

There is a high possibility that the blackening of mint leaves is caused by disease. Generally, mint will suffer from rust and leaf spot. If the blackening of leaves is caused by disease, it should be treated in time.

1. Rust: Mint rust is a disease caused by fungal infection. It is prone to occur during the continuous rainy season between spring and summer, and it is also easy to cause this disease when it is too dry. When the disease occurs, some yellow powdery substances will appear on the back of the leaves, and black spores will be produced later, causing the leaves to turn black. When the disease is serious, the diseased leaves will dry up and fall off, or even the whole plant will die. To treat rust, you can use sodium diacetate or Bordeaux solution to spray the diseased plants.

2. Leaf spot: Mint leaf spot is also a leaf disease caused by a fungus. It usually occurs in summer and autumn. After the onset of the disease, some dark green spots will appear on the leaves. Later, the spots will slowly expand and turn gray-brown, causing the leaves to turn black and wither. In severe cases, it will cause large pieces of leaves to fall off. To prevent and control leaf spot, diseased leaves should be removed in time, all infected leaves should be cut off and burned to prevent the spread of the disease. At the same time, Bordeaux or Mancozeb solution can be sprayed for treatment.