Mint is a long-day crop.Usually to ensure adequate light, if the environment is dark, the leaves of the plant may turn black.In this case, it needs to be placed in the sunny place, so that it can receive light all day, if the light is particularly strong, you can use 30% of the shading net to shade properly.
Peppermint likes moisture, and sufficient moisture is very helpful for its branches and leaves to grow.But if there is too much water and the environment is too humid, it may also affect the breathing of roots, which will lead to blackening of leaves.In this case, it is necessary to strengthen air circulation and loosen the soil properly so that water can evaporate as soon as possible.When watering at ordinary times, we should also pay attention to controlling the amount of water, not too much, especially not to produce water.
The demand of mint for fertilizer is not very high, as long as enough base fertilizer is applied when planting, there is little need for topdressing during the growth period.If the fertilizer is excessive, it is easy to cause fertilizer damage, burning the roots of the plant, making the leaves black.In case of this problem, it is necessary to remove the pot in time, take the plant out of the pot, wash off the old soil at the root, check the condition of the root, cut off the rotten place due to burn, spray a little carbendazim for disinfection, and prepare for re-planting after air drying.
Some diseases can also cause blackening of mint leaves, such as rust and spot blight.These diseases are usually caused by fungi, which have black spots on the surface of the leaves, causing them to wither and fall in severe cases, and killing the plant.When the plant is found to be diseased, the diseased leaves need to be cut off immediately and sprayed with Bordeaux mixture and other drugs.
