Yellow spots on orchid leaves are worrying as they appear due to many different reasons that even the toughest of orchids can succumb to. It’s one of the most common problems many orchid owners face.
However, if you catch it early, it is possible to treat or manage it and put precautions in place to avoid it in the future. So, if you’re wondering why your orchids’ foliage are growing yellow spots, you can adopt a few possible reasons and solutions below.
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What Is The Reason For Yellow Spots on Orchid Leaves?
The reason for orchid leaves can grow yellow spots is the result of overwatering, under-watering, excessive light exposure, and excessive fertilizer application. In addition, it can also be potting media stress, stress from repotting, temperature, humidity imbalance, nutrient imbalance, pests, diseases, and natural causes.
– Overwatering
Orchid plants are very sensitive to water, and a myriad of problems, including yellow leaves, can arise as a result of excess water. Even the most water-loving orchids require some breathing space in between watering sessions.
Typically, when you overwater your orchids, what happens is that the soil becomes waterlogged, which eventually leads to root rot. The problem is in the fact that once your plants’ roots have rotted, the leaves will get fewer nutrients and water than is required, as their roots will have lost the ability to transport these essential materials.
If you notice your orchid foliage going yellow or you notice yellow spots on the surface of your plant’s leaves, you need to get to the root of it as soon as possible to treat what’s wrong before it spreads. This can be an issue that the plant is losing its healthiness and the ability to thrive in the right way, and this is why it won’t produce abundant chlorophyll.
– Under Watering
When you water the plant less than the required amount it would be underwatered, and this can also cause yellowing orchid leaves. If you’re afraid of watering your orchids properly, you should expect yellow orchid leaves in very little time, as your plants will absorb less than the necessary amount of water and nutrients. In severe cases, the yellowing leaves will eventually wilt and die.
– Excessive Light Exposure
While many orchids thrive in bright, indirect light, there’s a limit to what they can survive. Whether your plants enjoy direct sunlight or artificial light, their leaves will turn yellow if it’s in excess. Excessive or direct sunlight will also cause your orchid leaves to dry out.
The leaves will eventually fall off unless you take steps to adjust the amount of light your plants receive. As you see clearly, the damage caused by excessive light is usually irreversible, so it’s best to be on the lookout for your plant’ tells that it’s receiving too much light.
– Excessive Fertilizer Application
Many orchids require the extra nutrition they receive from fertilizers. However, there comes the point when it becomes excessive, leading to the orchid leaves turning yellow. The quantity fertilizer that is being placed excessively is causing the plant to have weakened leaves.
This happens because applying excess fertilizers accumulates salts around the orchid roots, which messes with their ability to absorb water and nutrients. While orchids benefit from the nutrient-boost fertilizers, you need to be careful with how you apply them, as they need even less fertilizer than most other plants.
– Potting Media Stress
The potting media for different types of orchids vary, and many of the materials contained in them can last for several months at a time. However, these materials can break down over time, becoming useless for your orchids.
As a result, you will notice your orchid leaves turning yellow if you haven’t changed your potting media in a very long time, because this environment is not as good for the potting mix.
– Temperature Imbalance
Temperature is one of the important conditions for orchids’ growth. This is going to be clear to you because the effect will show on the plant’s leaves when the temperature becomes too low or too high for the orchid specie you’re growing. Orchids like consistent temperature ranges, so high temperatures above the ideal range or cold temperatures can cause temperature stress, leading to your orchids having yellow foliage.
– Repotting Stress
Another possible cause for your orchid leaves turning yellow is stress that occurs as a result of repotting. As it is necessary to repot your plants every once in a while, it is possible for your orchids to undergo a brief transplant shock during the process, leading to yellow foliage.
A change in potting media can involve removing roots, leaving your plants with fewer roots to absorb water in the potting media.
This will lead to some compensation from your plants to balance the available water with what is needed. Also, it can take a while for your plants’ roots to acclimatize to a new growth media. All these will affect the overall health of your plants in one way or another, and you will see that the plant isn’t in the same health as it used to be.
– Humidity Imbalance
Sometimes, leaves are yellow as a result of imbalanced humidity levels. While highly humid environments will cause mold and other diseases, low levels of humidity can lead to yellow leaves. In other words, if you place your orchids in a dry environment, their leaves will turn yellow and begin to fall off, because the right range that it needs is not filling its necessities, so this imbalance will stress it.
– Nutrients Imbalance
Orchids require a steady supply of nutrients to maintain strong, healthy leaves and to produce gorgeous flowers during their blooming season. Hence, orchid leaves turn yellow as a result of nutrient imbalance. These conditions will adversely affect your orchids, whether over-nutrition or nutrient deficiencies.
If your plants get less nourishment than they require, you will notice their leaves turning yellow over time, and they will generally look unhealthy. Iron, manganese, zinc, and hydrogen deficiency is a common occurrence that leads to orchids exhibiting the common symptoms of a deficit.
– Natural Cause
Sometimes, your plant’s leaves turn yellow due to the natural aging process. After your orchids have lived and bloomed for a very long time, it’s natural that their leaves die off, as they don’t last forever, and this is when they have become old.
In this case, leaves turning yellow is just a sign of the natural order of things. Many thin-leaved orchids, like boat orchids, inadvertently shed their leaves when two to four successive generations of pseudobulbs have been produced. Similarly, yellowing leaves frequently indicate the natural deciduous process that occurs during the dormancy period of several orchid species like Dendrobium.
– Diseases
Many diseases can cause yellow spots on your orchid’s foliage. Some of these diseases include bacterial brown spots, fungal leaf spots, and root rot. Many orchid species are prone to these diseases, which can express themselves in various ways. The fungal disease previously mentioned appears as dark brown or yellow spots on the underside of leaves.
If the disease persists, it can spread to other parts of the plant, resulting in death. The bacterial spot disease also expresses similarly, as brown patches on the surface of leaves. Except, in this case, the affected areas are usually watery and ill-looking. This disease spreads rapidly across the leaves, turning them yellow.
If you leave it unchecked, the disease can spread to the plant’s rhizome, ultimately leading to death. Root rot is another common disease that easily affects every known orchid, including Vanda orchids, Dancing-lady orchids, and Cattleya orchids. It occurs as a result of overwatering and terrible growth media drainage and expresses as yellowing leaves and wilting because the roots have weakened and the leaves are losing their color.
– Pests
Many pests, including Thrips, Spider mites, Mealybugs, white flies, and Scale Insects, feed on all kinds of orchids, depleting the nutrients in their leaves. For example, Moth orchids are plants of interest to four of the abovementioned pests. As many of these pests are small, some invisible to the naked eye, detecting them on your orchids can be challenging.
However, some tell-tale signs, like yellowing leaves or unhealthy-looking plants, will alert you to their presence over time. If you catch an infestation very early, you will be able to get rid of these pesky pests and save your precious orchids.
What Are Ways To Fix Yellow Orchid Leaves?
The ways to fix yellow orchid leaves are by watering them properly, placing them in indirect light, and applying the right fertilizer. In addition, you must also set the size of the new pot, adjust the temperature, fix the surrounding humidity, apply remedies for diseases, and tackle pests.
– Start Watering Properly
Suppose you notice that you’re overwatering your plants. In that case, the apparent course of action is to stop watering for a while, allowing the potting soil to start drying out a bit or completely, depending on the severity. For subsequent watering, you should let the water dry out, such that the soil’s surface is dry to the touch, between watering sessions, so that this ensures that your orchids stay waterlogged.
Like with overwatering, you want to do the opposite of what is causing the problem; in this case, add more water. To ensure the issue is under watering, you can check the potting soil using your finger.
If the soil is dry at the bottom, then you’re not giving your plants enough water. You can fix this problem by watering your plants deeply and frequently, at least once or twice weekly, depending on the orchid species, leaving short periods between each watering session to allow the soil to dry out a bit.
– Place it In Indirect Light
To fix yellow foliage caused by excessive light exposure, you’ll need to adjust the position of your orchids. Select a spot that gets bright but indirect light for them. Also, avoid placing them too close to windows.
However, you can protect them from the sun by filtering the light using sheer curtains if you have to. Placing them behind furniture and other items to reduce the impact of the sunlight also helps, to protect it from harsh rays of sun.
– Apply The Right Fertilizer
First, you’ll need to reduce the frequency or dosage of the fertilizer you use for your plants. It’s also important that the fertilizer you’re applying is an orchid-grade fertilizer, as other types of fertilizers can have dangerous effects on the plants. Flushing can help eliminate the soil’s salt build-up from excessive fertilizer application.
You only need to pour enough water into the potting mix to let the salts sink to the bottom and out of the mix. Additionally, a solution of dilute fertilizer, which is around half or a quarter of its strength, will help to prevent over-fertilizing.
You can remedy yellow foliage caused by nutrient imbalance, such as nutrient deficiency, by fertilizing your orchids with orchid-grade fertilizer. A well-balanced fertilizer is ideal for providing your orchids with all the essential nutrients they need, and they will grow in such a healthy manner instead of showing weak foliage.
Remember to apply fertilizers in moderation to prevent root burns and salt accumulation. Also, it’s best to follow the dilution instructions on the fertilizer packages, to ensure your plants are getting the appropriate nutrient concentration.
– Set The Size of the New Pot
As orchids generally require repotting every few years, repotting is unavoidable. Selecting the right-sized pots for your plants can significantly reduce potting stress. The new pot should be slightly larger than the old one to allow room for growth, and this way, you would not water it excessively.
Moreover, as you go ahead and repot, you must also be mindful of the ways you must avoid potting stress, and that is by selecting the appropriate potting media for the type of orchids you’re growing and making sure they’re well-draining and the materials allow proper aeration. Also, pay close attention to parameters like soil pH, as it can play a massive role in causing problems for your plants.
– Adjust the Temperature
If you’re growing your orchid indoors or in a greenhouse, you can constantly adjust the temperature in your home to suit the orchid specie you have. Most orchids will thrive in warm temperatures during the day and cooler temperatures at night.
For orchids growing outdoors, moving them to a suitable position with cooler or warmer temperatures is the best course of action, and this will help it reduce the stress that it is going through.
– Fix The Surrounding Humidity
Once you have identified that your orchids are suffering as a result of low humidity, you can adjust the humidity of your orchids’ surrounding by increasing or reducing them. Since the yellowing of leaves is typically caused by low humidity, you will have to increase the level of humidity in this case.
You can manually increase the humidity level using a spray bottle or pebbled tray. You can also use a humidifier to adjust the humidity as needed, or you may spray with a bottle around the plant’s air to adjust the balance.
– Apply Remedies to The Diseases
Several diseases have different remedies; however, one constant practice to prevent their spread is to cut yellow foliage by hand or using sterilized cutting tools. This prevents the diseases from reaching other parts of the plants. In short, apply fungicides because they can also help prevent the spread of some of these diseases and infections.
You should also prune your orchids when you notice yellow spots on their leaves if diseases cause it. Select only the affected leaves and destroy them to manage the spread. However, if the yellowing is a result of nutrient depletion, you should hold off on cutting the leaves, as cutting them off can further damage your plant unnecessarily.
– Get Rid of the Pests
Once you notice the tell-tale signs of pest infestations, you will need to act quickly to manage their damage. Most pests that cause yellowing foliage can be hand-picked, especially when only a few of them exist.
On the other hand, you will need strong plant-safe pesticides to destroy these pesky pests for a significant infestation. Repotting is an excellent idea for all kinds of pest infestations, as it ensures that no pest eggs or larvae are left behind, and this way, the plant would be set in a new potting mix.
– Prune The Old Leaves
The best thing to do for your plants is to provide them with all the necessary growth conditions to keep them as healthy as possible for a very long time, which is why you can prune them. Once their leaves start to turn yellow as a result of the natural aging process, there won’t be any issues as new growth will follow.
Conclusion
In the article above, we’ve compiled a list of the possible causes of yellowing foliage and some suitable solutions. Remember the following keynotes;
- If you notice your orchid foliage turning yellow after repotting, your plant is more than likely going through transplant shock.
- Excessive direct sunlight can cause your orchid foliage to develop yellow spots. Root rot is a major orchid disease that can cause yellowing of the foliage.
- An infestation of several pests, including mealybugs, scale insects, thrips, spider mites, and white flies, will cause orchid foliage to turn yellow and drop prematurely.
- Trimming leaves affected by pests or diseases can help stop their spread.
- Repotting, flushing growing media with water, applying pesticides and fungicides, and cutting off affected leaves, depending on what is causing the problem.
Once you figure out the problem your orchid is facing, you will be able to take the proper steps to bring your plants back to their healthy state.
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