When your orchid’s leaves are turning unnaturally yellow, it is not a good sign. It means there is something wrong with your plant that you will need to address and remedy as soon as possible.
The most common cause of yellowing orchid leaves is overwatering. Other causes include too much light, changes in temperature, transplant stress, too much fertilizer, not enough nutrients, exposure to chemicals, or disease.
In this article, we will learn about the different causes of yellowing and how to remedy each one.
Why are my orchid’s leaves turning yellow?
The orchid is overwatered
Overwatering is the most probable cause of an orchid’s leaves turning yellow. When its roots are overwhelmed with excess water, it can no longer take in any more water or nutrients. The orchid’s leaves will turn more yellow and mushy the more the roots are compromised. This is called root rot, and if allowed to persist, can lead to the death of the plant.
Orchids do not really need a lot of water, so the best way to control your watering frequency is to check the soil in the pot. If the soil is damp, wait a few more days before watering again, but if it is dry you are free to give it a reasonable amount of water. When it comes to orchids, always remember that it is exponentially better to underwater your orchid than it is to overwater it.
The orchid is getting too much sunlight
In their natural habitat of rainforests, orchids live under the generous shade of the tree canopy. They cannot tolerate direct sunlight and if they are left in an area with full sun, their leaves will turn yellow from sun damage, possibly even with burnt tips. Orchids prefer indirect light.
Inside your home, place the orchid in a north- or east-facing window during the winter so they get a decent amount of light each day. You can transfer them to a south- or west-facing window in the summer. If the light is still too intense even through a window, you can try adding a sheer curtain to lessen the intensity or move the plant further away from the window.
The orchid is not used to the extreme cold or heat
If you keep your orchid indoors, you do not have to worry about the temperature being too low for it. If you keep it outdoors, however, it might have a hard time adjusting to changing temperatures.
Orchids like to be kept in places where the temperature is somewhere between 60 and 80 degrees Fahrenheit. If they are subjected to temperatures below 60 or above 80, the plant will experience stress. This can manifest as yellowing and even dropping of leaves. If the stress becomes too much, the leaves can turn brown or black and lead to plant death.
You can monitor the temperature of your orchid’s environment by purchasing a thermometer which you can use to periodically check the temperature of the area.
The orchid has transplant stress
When you buy an orchid plant from the store where it has lived for the past couple of months, taking it directly into your home with a new set of unique living conditions can stress the plant. It’s leaves could turn yellow and may even fall off. This can also happen when you change apartments or houses.
There really is not much you can do for an orchid going through transplant stress, aside from making sure its new home has ideal living conditions. Providing the plant with the best care can make the transition easier on it.
The orchid has had too much fertilizer
You give fertilizer to your orchids to encourage better growth, but sometimes too much of a good thing can be bad for your plant. Giving too much fertilizer can add too much zinc, copper and calcium into the soil. If these other nutrients are too overpowering, the plant will be unable to absorb iron, which it also needs. If the orchid does not have its normal iron levels, its leaves will turn yellow; this condition is called chlorosis.
Just be sure, when giving your orchids fertilizer, that you do not overdo it and give just the right amount. You actually need to dilute the fertilizer for orchids to about a half or a quarter strength. Orchids are often sold while in bloom, so you do not need to fertilize at that time. It is best to read up on how often orchids bloom, and fertilize accordingly.
The orchid does not have enough nutrients
Inversely, if you do not give your orchid enough nutrients, it will also result in the plant’s leaves turning yellow. Soil has nutrients that it can provide to your plant, but over time these will deplete and you are going to have to provide the missing nutrients through fertilizer. The nutrients that most commonly run out are nitrogen, zinc, iron, and manganese.
This problem can be easily remedied by purchasing a fertilizer made for orchids and to do just as the instructions say on the package.
The orchid was exposed to chemicals
When you live in an area where the tap water is treated with chlorine, your delicate orchid may not react well to this, and this could manifest as yellowing leaves.
You can figure out if the water is causing the yellowing by requesting a water test. If the results come back with chlorine or any other element that may be harmful to your orchid, you can choose to collect and only use rainwater on your plants, install a home filtering system, or buy filtered water to use on your plants.
The orchid is diseased
Diseases that attack orchids include root rot, fungal leaf spot, and bacterial brown spot.
Root rot happens when the plant’s roots drown in overwatered soil in a pot with no drainage holes. Root rot takes effect quickly and will turn the leaves yellow, eventually killing the plant. You can save the orchid if there are still healthy roots left and if you are able to remove the rotten roots in time.
Fungal leaf spot also causes yellow areas to appear on the orchid’s leaves. These spots will eventually turn brown and even black if not treated immediately with fungicide. Remove all infected leaves and burn them so they do not infect other plants.
Bacterial brown spot will appear as yellow or brown spots on the orchid’s leaves. This disease is common among orchids that are kept in humid areas. You can treat the plant by removing all the affected leaves and burning them. Make sure you sterilize the scissors after each cut on the plant so that the disease does not spread to the healthy parts of the orchid. You can use a bacterial spray on the plant to prevent any further spread of the disease.
Conclusion
If you see any leaves on your orchid turning yellow, you need to narrow down the cause of the discoloration immediately so you know how to remedy it.
The yellowing of the leaves can either be due to overwatering, too much light, changes in temperature, transplant stress, too much fertilizer, not enough nutrients, exposure to chemicals, or disease.
Most of these problems are easily fixed, provided you catch the problem in its early stages. Your orchid should bounce back in no time.
Image: istockphoto.com / alexytrener