Why won't the leaf core of an orchid open and instead grows into a columnar shape?

When an orchid's leaf core won't open and becomes columnar, it means it has stopped growing, or is growing very slowly, so the leaf core stays closed for a long time. The reasons for slow or stopped growth in orchids are many, but the three main ones are: unsuitable temperature for growth, lack of fertilizer, and too little watering. Below I'll explain the formation of these three causes and the detailed solutions for each.

Unsuitable temperature

For the vast majority of orchids, when the temperature is between 15 and 25°C, growth is fairly fast; when the temperature is below 10°C or above 28°C, growth slows down and the plant gradually enters dormancy or semi-dormancy. The lower or higher the temperature, the deeper the orchid's dormancy and the slower the growth. So when winter weather is fairly cold or summer weather is fairly hot, it is normal for new shoots and new leaves of orchids to grow slowly or stop growing. Once the temperature returns to a stage suitable for growth, they can grow quickly again and the leaves open quickly.

Lack of fertilizer

If there is no temperature problem and the orchid's new leaves and shoots grow slowly and the leaves won't open for a long time, you should consider whether it lacks fertilizer. The main symptoms of fertilizer deficiency in orchids are: slow growth, yellowing leaf color, and diminished glossiness. If the new leaves of the orchid won't open due to lack of fertilizer, you can appropriately apply a little nitrogen fertilizer or a balanced compound fertilizer of nitrogen, phosphorus and potassium, once every ten to fifteen days, and the new shoots and leaves will resume growth. Note that this refers to when the temperature is suitable for growth; when the temperature is too high or too low, even if the orchid lacks fertilizer, fertilization must be handled with caution. Because when the temperature is unsuitable, the orchid's metabolism is slow and its demand for fertilizer is not strong, making fertilizer burn easy.

Too little watering

Orchid growth cannot be separated from water support. If you water too little for a long time and the growing medium is on the dry side, it will be difficult for new seedlings and new leaves to maintain good growth, and they may even gradually turn yellow and dry up. So when watering orchids, be sure to follow the principle of watering when dry and letting dry between waterings; when it is dry, water. Some flower enthusiasts dare not water when the weather is fairly hot, for fear of root rot, and thus cause orchids to suffer from water shortage, poor growth, or even direct death by drying out. Orchids that get insufficient water, besides growing slowly, also have leaf color and glossiness that are not strong, looking not very attractive. However, I only suggest appropriately increasing the amount of watering when watering is on the low side; if your watering is fine, then in summer don't water too much, because in a hot and humid environment the roots rot very easily.

Conclusion: From the above analysis, it is not hard to see that the reason your orchid's new leaves won't open and have become columnar is mainly that the temperature is too high and the orchid plant has entered dormancy. It is recommended to continue caring for it well, avoid water entering the leaf core, and after the weather turns cool in autumn, appropriately apply a little compound fertilizer; then it will naturally open and grow smoothly.