The mint leaves black may be watering way problem, generally to the mint watering time need to follow the principle of dry watering, potting soil is not dry, do not just water, wait for the soil to dry out a one-time thorough watering. Watering the best use of rice water, can be very good for the mint to provide some camping material, with ordinary water watering can also be, but pay attention to do not directly with tap water, need to first tap water in the sunshine to dry for a period of time and then use.

Second, air and light

Mint is more like light, if the light is not enough will easily lead to yellow and black leaves, so breeding time is best to be placed in a sunny place, if there is no light in the corner of the indoor culture, you need to every two or three days will be put into the potted plants in the sunny place in the sunshine for a day or two, and so on and so forth, but pay attention to the summer. However, it should be noted that in the summer to avoid sun exposure, the need for appropriate shade treatment.

Three, the cause of treatment

The mint leaves black also has a high probability of being caused by disease, generally mint will suffer from rust and spot blight, if the disease caused by the leaves black, to be treated in time.

1, rust: mint rust is a disease infected by a fungus, generally in the spring and summer alternating rainy seasons are prone to the onset of drought is also prone to trigger this disease. At the onset of the disease, some yellow powdery material will appear on the back of the leaves, and later on, black spores will be produced, resulting in the blackening of the leaves, and when the disease is serious, the leaves will dry up and fall off or even the whole plant will die. Treatment of rust can use sodium dichloride or Bordeaux solution to spray the diseased plant.

2, spotted wilt: mint spotted wilt is also caused by a fungal leaf disease, usually in the summer and fall seasons, after the onset of the leaf will appear some dark green spots, the late spots slowly expand and turn grayish-brown, resulting in blackened leaves and withered, and when the disease is serious, it will cause a large number of leaves to wither. Prevention and control of spotted wilt disease should be timely removal of diseased leaves, all infected leaves will be cut and burned to prevent the spread of the disease, while you can spray Bordeaux or zinc diclofenac solution for treatment.