What to do when Cymbidium sinense leaves turn yellow and black? Solutions for root rot
As is well known, orchids are very precious and beautiful flowering plants, and there are many varieties of them; Cymbidium sinense is one of them. Although Cymbidium sinense is not a rare variety among orchids, like other orchids it needs careful care. If the care methods are improper and cause the leaves to turn yellow, affecting the appearance of the whole plant, it is simply unbearable. So if Cymbidium sinense develops yellowing and blackening leaves, how should we handle and solve it?
What to do when Cymbidium sinense leaves turn yellow and black
1. Overwatering
In winter and spring, watering around sunrise is best, and misting is also needed to increase air humidity to benefit the growth of Cymbidium sinense. In summer and autumn, water around sunset, and it is best for the leaf surface to be dry before nightfall. When the surface of the substrate is on the dry side, water as soon as possible, and do not let it stay too dry for too long. Also, the watering method must be correct; watering along the edge of the pot is better.
2. Overfertilizing
Fertilizing should be moderate, not too much. During the growing period, fertilize once a week; in autumn and winter, Cymbidium sinense grows slowly, so fertilizing once every 20 days is enough. When fertilizing, do not pour it onto the leaves; after fertilizing, pour a small amount of clean water to wash away fertilizer remaining in the soil. Fertilizing must be done on a clear evening; fertilizing on cloudy days risks root rot.
3. Temperature too low
Pay attention to freeze protection for Cymbidium sinense; do not place it outdoors in winter. The most suitable temperature for the growth of Cymbidium sinense is 18°C~28°C. In winter, below 10°C it grows slowly and enters dormancy. But the winter temperature also must not be too high; above 25°C it will affect the dormancy of Cymbidium sinense and affect the next year's growth.
4. Insufficient light
Let it see more sunlight appropriately; especially the morning light before 9 a.m. is very beneficial to orchid growth and flowering. On clear days in winter and spring, there should be 40%-50% shading; on clear days in summer and autumn, there should be 80%-90% shading.
Solutions for Cymbidium sinense root rot
1. Cut off the rotten parts
When root rot is found in Cymbidium sinense, take the plant out of the pot and, according to the degree of root rot, cut off the roots and stems that are moldy, blackened, or hollow, keeping the parts that are not rotten. At the same time, cut off diseased leaves with spots or yellowing. As long as the bulb is not completely rotten, it can survive.
2. Change the soil
Break old red bricks into pieces the size of hickory nuts and mix them with bark at a ratio of 1:1. If only soil is used, also add crushed red bricks; put the large pieces at the bottom, and the small pieces and soil on top. However, to prevent the plant from being infected again by pathogens, when replanting, change to a clean plain clay pot, or choose uncontaminated plain sand for planting.
3. Spray chemicals
When a plant has root rot, there must be some kind of pathogen, so promptly spray a fungicide; choose carbendazim to drench the roots, 2~3 times.
4. Control water and fertilizer
In the subsequent care, control water and fertilizer well. Water by the principle of watering when dry and stopping when wet; stop when water flows out of the bottom of the pot, and water promptly when the pot surface becomes dry or even whitish. For orchid plants that have just been repotted, do not fertilize before they resume growth.
How to water Cymbidium sinense
Usually when growing Cymbidium sinense indoors, the air circulation is slower, and at this time water evaporation is correspondingly reduced, so watering an appropriate amount is enough. We should maintain the soil in a semi-dry state, and at most water once about every 10 days. Watering should ensure the soil is thoroughly moistened; when you see a small amount of water seeping out from the bottom of the pot, you can stop watering. While watering, you can also wipe the leaves with water along the way, which can make the leaves look more glossy.
What to do if Cymbidium sinense leaves curl
1. If it is a disease, you can dilute potassium permanganate and spray it, which can also add elements such as Mn and K. If it is hormone-type phytotoxicity, you can use some Aopuer; note that when using hormones, the dosage should be smaller in hot weather, and do not get it on new leaves.
2. If the weather is too hot, you can help it undergo training to resist drought during the care process; after it sets fruit, you can add water and fertilizer at the right time and help it shade light. If it is caused by too much wind, you can gradually let in wind to train it.
3. If it lacks phosphorus, you can add phosphorus to the soil or leaves; for example, monopotassium phosphate only needs a dosage of 0.3 percent. If it lacks magnesium, you can use magnesium sulfate to help it.
Through the above content, I believe everyone has gained some understanding of the care techniques for Cymbidium sinense. In fact, as long as you are patient and master the correct care techniques, growing beautiful and elegant Cymbidium sinense is no problem; placing it in a study or office is very suitable.