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Yellow stems jeopardize the aesthetic appeal of orchids, which is one of the main reasons we grow these houseplants. The best orchids are those with a green stem and colorful blooms.
If your orchid flower spike turns yellow, it could be due to a number of reasons. We’ll help you troubleshoot the most common issues that can cause your orchid flower spikes to turn yellow and how to prevent them from happening again.
The orchid spike is a flowering stem that emerges from the center of the plant, often growing multiple flowers. It can be identified by its thin, green appearance.
However, if your orchid’s spike is turning yellow, this may be a sign that something is wrong with your plant.
Orchid stems can turn yellow due to a variety of reasons. The yellowing can be a result of overwatering, too much sunlight, fungal infections, nutrient deficiency. and others.
Let’s look at these causes in detail…
1. Overexposure to Direct Light
Although orchids are tropical plants, they thrive in the shade of large trees with deep canopies, allowing very little light to enter through.
This is why lengthy sunlight exposure can be detrimental to the plant’s health, causing leaves, stems, and flowers to turn yellow, brown, or black.
Sunlight carries ultraviolet rays which are harmful to different plants including orchids in large quantities and for prolonged periods of time. The effect will show up as burning on leaves and petals, often turning them yellow and brown in color.
When too much light passes through the orchid’s leaves, it can burn them unexpectedly and make them yellow.
Move your orchid away from direct sunlight as soon as you notice its leaves turning yellow. Gradually adjust the plant into its new location by first exposing it to morning light (6-9 am),
The best solution is to provide your orchid with dappled light. This refers to partial, filtered light that is warm yet not harsh on the plant itself.
To do this, all you need is a sheer curtain, which you should hang between your orchids and the window so their leaves won’t get burned by the sunlight passing through it.
If possible, you may want to move your orchids into a room where they won’t receive too much sun exposure at all during summertime.
2. Not Getting Enough Water:
The second reason orchid spikes will yellow is not enough water consumption through the potting media.
Either there is not enough water being supplied, as in quantity, or the frequency needs to be upgraded by a day or two.
When orchids don’t get enough water, they instinctively shed their leaves to conserve the little water they have by minimizing transpiration.
This is an adaptation to their natural environment of semi-arid climates, where rain may fall only once or twice a year. When you see your plant dropping leaves, this is a sign that it needs more water.
But this doesn’t always work. The plant may still turn yellow and die, despite its efforts to survive.
If you notice that the plant is losing its healthy green color and turning yellow, you can soak it in a bucket of water overnight.
This should restore its strength and replenish the moisture it needs to stay alive, and hopefully prevent it from dying.
Orchids are native to tropical regions around the world, so they like lots of moisture and humidity. However, too much water can cause root rot and will eventually kill your plant.
Too much water is just as dangerous as water deficiency. Poor soil drainage leads to water-logging around the orchids’ roots.
As plants need air circulating around their roots for photosynthesis and respiration through the roots this can lead to root rot and eventually death.
This is why it’s important to use a well-draining potting medium like coco chips. Water your plant when it has dried out about halfway down from the top of its potting media, and then soak it thoroughly but let excess drain out of its bottom drainage holes immediately.
If you are using a clear plastic pot, take note of how long it takes for the potting media to dry out
While orchids like humidity, they don’t like soggy soil. If you suspect that overwatering is causing your orchid’s stalk to turn yellow, reduce how often you water it and check the soil for mold and mildew.
4. Lack of Humidity:
Most orchids are epiphytes which means they grow on other plants and derive their moisture from the air around them.
If you live in a place with low humidity (dry air), especially during the winter months this can be a prime culprit for yellowing spikes and leaves on your otherwise healthy plant!
In the wild orchids grow in a humid tropical environment. They are accustomed to humidity levels of 40-60%. If there is not enough humidity in the air, the orchid could sense this difference, resulting in moisture stress, inducing a yellow color.
The solution to this is simple: Get a humidity tray, a mister, or even a humidifier if you want to go all out!
5. Disease or Pest Infestation:
The fungal infection can also be a reason for the yellowing of stems. The fungal infections thrive in warm wet environments which are created by overwatering.
Insects like mealybugs can cause yellowing leaves on your orchid because they drink sap from the plant, which stresses it out and causes it to dehydrate and wilt with yellow leaves.
Fungi such as black rot, root rot, or leaf spot can also cause yellowing in orchids. You’ll also notice that your leaves are mushy and see black spots on them as well as roots turning brown with a foul odor.
Botrytis Blight, Pythium Root Rot, and Bacterial Leaf Spot are common diseases that cause the orchid to wilt and die quickly. Look for dark spots on your leaves and mushy stems (root rot) when trying to identify these diseases.
Remember, if the whole orchid stem is turning yellow, it’s likely due to bacterial or fungal disease.
5. Nutrient Deficiencies:
Nutrient deficiencies can also be one of the causes of yellowing in orchids. A lack of potassium, magnesium, zinc, iron, nitrogen, etc can cause this problem.
Also if you are using a general-purpose fertilizer, be careful that you are not giving your plants too much phosphorus as it can cause leaf tips to turn yellow and roots to turn brown.
Unfortunately, too much phosphorous can harm orchids by preventing them from absorbing other minerals they need to grow. These include manganese, iron, zinc, and copper.
6. Hostile Environment:
Extreme temperatures are another reason why your orchid spike might be turning yellow.
If you expose your orchid to extreme temperatures such as freezing cold or extremely hot, then most likely your orchid spike will start to turn yellow as a sign of stress/shock.
7. Unclean Water:
Orchids are exotic and delicate plants, prone to many diseases and disorders. One of the most common reasons for the orchid stem turning yellow is the high level of toxins like chloride or fluoride in the water.
The toxic elements in water build up over time.
Symptoms are yellowing, browning, and blackening at the base of the orchid spike.
Orchids have a natural life cycle and fading flowers, wilting blooms, and the drying back of the orchid spike that turns yellow then brown is a normal part of the orchid’s life.
If you are growing a Phalaenopsis orchid, then it is normal for the orchid spike to turn yellow after flowering. It is also normal for the spike to turn brown and eventually fall off.
The most important thing to do when your orchid stem turns yellow is to identify the underlying cause of the problem and take action to correct it.
- Move the plant to a different position with limited light reach.
- Work on the perfect watering schedule for your orchids,
- Use Clean Water. Rainwater is one of the best suitable options for this.
- Use a good orchid fertilizer in place of general fertilizers.
- Also when it happens, you shouldn’t rush to kill the whole plant. Instead, you should only cut off the yellowed stems.
One of the most common problems we see in orchid plants is that their stems turn yellow. Although not a critical condition, it can lead to some very serious problems if left unchecked. We hope this article helped you understand the reasons why your orchid stem turns yellow and what you can do about it.
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