Orchids, with their delicate and graceful appearance, have long been used as ornamental plants for homes. However, their beauty isn’t easy to maintain, and homeowners need to exert extra effort to keep their leaves’ vibrant and lush green color.
Hence, it can be pretty concerning and stressful when their beautiful green leaves suddenly turn yellow. While yellow is generally a happy and bright color, it can be a sign of stress in your orchid, so you need to take it seriously.
In this article, we’ll discuss the possible reasons why your orchid leaves are turning yellow and provide some treatment and prevention tips to ensure you enjoy your orchids for a long time.
Natural Aging Process


Some plant owners start to worry when their beloved orchids turn yellow, and it’s understandable, as it can be a sign of several problems.
However, there are instances when the yellowing of leaves is just a result of the aging process that every plant goes through.
While orchids can typically live for over a decade, their lifespan is finite, and as they age, the leaves will naturally turn yellow and eventually fall off. This is the orchids’ way of prioritizing the new leaves that are about to emerge.
When the yellowing begins from the bottom part of the plant, this is usually the case. The yellowing of the plant won’t harm the orchids’ overall health, so it’s not something to stress over.
Tips to Prevent Yellowing Caused by Natural Aging Process
Yellowing caused by the natural aging of the orchids is inevitable, and you can do nothing to save the leaves that have turned yellow. Just let them turn yellow and wither.
It’s important that you don’t forcibly remove the leaves yourself. Although they may not be aesthetically pleasing, removing them may increase the risk of diseases and cause harm to the whole plant.
Once the leaves are completely withered, you can use a clean knife to remove them at the base.
Change in the Environment


Orchids are extremely sensitive to changes in their environment, which is also one of the reasons why the plant is especially harder to grow compared to others.
Even minor changes, like putting it in a different room, or major changes, like seasonal shifts, can affect the orchids’ health.
They are so sensitive to environmental changes that they may turn yellow when you bring them home from the store. This is because the change in temperature, lighting, and humidity all cause stress to the orchid.
Prevention and Treatment Tips for Yellowing Caused by Environmental Change
If the orchid turns yellow after bringing it home from the store, just look for a great place to put it and provide it with ideal growing conditions like high humidity, bright indirect sunlight, and warm room temperature.
This should stop the other leaves from turning yellow.
It’s also advisable to make little changes in the environment every now and then to keep track of what’s affecting your orchids’ health. This way, you can make future changes without much damage to the plant.
Temperature Stress


Fluctuating temperatures and excessive heat or cold can cause severe stress to orchids. A change in temperature can cause the orchids’ leaves to turn yellow within hours.
If the temperature continues to rise or fall, the plant will not only suffer from yellowing, but it may die altogether.
Generally, orchids prefer a temperature of 60°F to 80°F, which is the typical room temperature for most homes. Anything below or above this can cause stress and yellowing to the plant.
However, this temperature range is just the average preferred temperature of the majority of indoor orchids. Some species may require hotter or colder temperatures, so it’s best to check the specific requirement of your plant.
Prevention and Treatment Tips for Yellowing Caused by Temperature Stress
Always monitor the temperature in your home or at least in the room your orchid is placed. This way, you can detect the changes and interfere when there’s a significant change.
It’s especially important to monitor your temperature during summer and winter, as you’re more prone to using air conditioning and heating units in these seasons.
Humidity Levels


Orchids love humid environments, as they help reduce water loss through transpiration. Low humidity can cause dehydration to the plant and yellowing of the leaves.
However, extremely high humidity can also cause bacteria and mold to grow, which can also damage the leaves and cause them to turn yellow.
Prevention and Treatment Tips for Yellowing Caused by Humidity Levels
When your home has low humidity, consider putting the orchid on a humidity tray, which can help keep the plant moist. Humidifiers can also help keep the humidity at home at an ideal level.
When the humidity level at your home is extremely high, consider using a dehumidifier or an air conditioning unit to reduce the moisture in the air.
If you have the means, keeping a humidity level sensor is also advisable.
Insufficient or Excessive Sun Exposure


Orchids can be sensitive to light levels. Both excessive and insufficient sun exposure can turn their leaves yellow and kill the plant.
They typically grow under the shade of a huge canopy of trees, so they’re not used to receiving direct sunlight. If they’re placed in areas that get direct sunlight, their leaves may turn yellow and burn.
However, this doesn’t mean that they should be kept in areas with extremely low light, as all plants still need sunlight. This is why growing orchids can be very challenging to some.
Prevention and Treatment Tips for Yellowing Caused by Sunlight
When there’s already yellowing in the leaves, determine first if it’s because there’s too much or too little light in the areas before making necessary actions. You can either move it in a much shadier place or near the windows.
To prevent this from happening again, keep the orchid in areas where they’ll only receive indirect light. We recommend putting curtains or screens in windows to help minimize the amount of light they receive.
Nutrient Deficiency


Yellowing leaves can also be a sign of nutrient deficiencies in the orchids. This usually happens when you don’t feed the orchids with enough fertilizer.
Although orchids are not heavy feeders, their potting mix may still not be enough to provide the plant’s required supply of nutrients.
However, too much fertilizer may also interfere with the plant’s iron intake, especially when you use the wrong fertilizer. Even with constant feeding, the leaves will still turn yellow when the orchid is not receiving the right ratio of nutrients it needs.
Prevention and Treatment Tips for Yellowing Caused by Nutrient Deficiency
Use fertilizers made specifically for orchids, as they typically have a balanced ratio of nutrients. The fertilizer should also include a feeding schedule that you can follow to ensure your orchid leaves don’t turn yellow.
Under-Watering


Under-watering causes dehydration to the orchid and prevents it from absorbing the necessary nutrients it needs to grow and stay healthy.
When the orchid isn’t receiving enough water and nutrients, it will start shedding some of its older leaves to prioritize the newer ones. This causes some leaves to turn yellow and dry up.
When this is untreated, under-watering will also damage the roots and make them brittle, causing the orchid to die.
Prevention and Treatment Tips for Yellowing Caused by Under-watering
To prevent under-watering, it’s essential to not let the soil completely dry. Always check the soil with your fingers to see if there is still moisture and if the plant doesn’t need another watering.
It will take a few days before the orchid completely recovers, so don’t panic when the yellowing continues or the leaves start to fall off. If you provide the plant with necessary care, new leaves will eventually grow.
Overwatering


While it’s true that under-watering is detrimental to the orchids’ health, overwatering can cause just as much damage. This is because overwatering can cause root rot and create an ideal environment for bacteria to grow.
Additionally, when there’s too much water in the soil, the potting mix may become saturated and suffocate the orchid. This will cause some of the leaves to turn yellow and eventually wither.
Prevention and Treatment Tips for Yellowing Caused by Overwatering
Use well-draining soil and pots that have drainage holes to reduce the chances of overwatering. Don’t water the plant when the soil is still visibly moist, as it’s very likely that it doesn’t need water yet.
If you’ve already overwatered your orchid and root rot has occurred, repot the orchid and remove the damaged roots. This way, your orchid can start anew, and recovery can be a lot easier.
Use of Hard Water


The type of water you use can greatly affect the health of your orchids.
Hard tap water usually contains chemicals like chlorine which orchids may have a hard time processing, causing damage to the plants.
Hard tap water can also hinder the plant’s ability to absorb nutrients when they have a high presence of calcium and magnesium. The lack of nutrients will then cause the leaves to turn yellow.
Prevention and Treatment Tips for Yellowing Caused by Hard Water
Instead of using tap water, it’s advisable to collect rainwater, as it usually doesn’t contain chemicals and minerals that can be detrimental to the orchids. Just make sure to check your local laws first, as some states prohibit the collection of rainwater.
Another choice you have is to use a water filtering system to ensure that the water is stripped of harmful chemicals before it’s used on the orchid.
Tap water can still be used if it’s the only option you have, but you have to leave it overnight first. This will allow chlorine to dissipate, reducing the risk of harming the plants.
Potting Stress


Orchids can suffer from stress when they’re frequently repotted. They enjoy growing in cramped pots, so repotting them when you think they’re too big for their home can cause more harm than good.
If the roots are still green, there’s no need for you to report, even when you think the roots are already way too compact.
If you repotted your orchid and the leaves turned yellow, then it probably suffered shock from the repotting and will need more time to adjust to its new environment.
Prevention and Treatment Tips for Yellowing Caused by Potting Stress
When the leaves have already started turning yellow after repotting, there’s not much you can do but let the leaves turn yellow and continue providing the orchid with the necessary care.
To prevent this from happening, only repot the orchid once every two years or whenever the roots are turning gray.
Fungal or Bacterial Infection


Fungi and bacteria can grow from the leaves or roots of the orchid, which can damage it and turn the leaves yellow. Growth of these is oftentimes caused by too much watering, as they thrive in soils that are consistently moist.
When the plant suffers from fungal and bacterial infection, the orchids may stop growing, and brown or black spots may appear on the leaves.
If the yellowing is paired with a foul smell coming from the orchid, then it’s probably caused by fungi and bacteria.
Prevention and Treatment Tips for Yellowing Caused by Fungal or Bacterial Infection
Apply fungicide to the orchid to avoid further damage. You should also remove the affected leaves with clean scissors to stop the fungi from spreading.
Keep the orchid away from rooms with extremely high temperature and humidity levels, as they can promote fungal and bacterial growth. It’s also important not to overwater your orchid to avoid root rot.