Orchid with yellow leaves is not uncommon, but they may be an indication that your plant needs a little help. While it is natural and normal for the oldest leaves to yellow and fall off at some point, it is crucial to pay attention to the younger and newer leaves turning yellow as a warning sign of trouble.
Yellow and wrinkled leaves of an orchid can be an indication of illness, a consequence of mistakes made in the process of leaving at home, or a completely natural process. Let us have a look at all the reasons why your orchid is turning yellow and what you can do to fix the problem.
1. Natural Death of Old Foliage
As your orchid grows older and each leaf reaches the end of its life, yellowing is inevitable. All orchid leaves turning yellow ultimately die off. There is no harm to the plant by letting a leaf turn yellow and dry up.
You can trim the yellowing foliage once they begin to change color to keep the orchid looking fresh. Pay attention to the newest leaves. Are they dark green, well-formed, and rapidly growing? Then yellowing is likely a byproduct of the natural aging process.
If there are no new leaves forming and the current ones are losing their color, the cause is likely elsewhere.
2. Too Much Direct Sunlight
Yellowing in response to light levels is challenging since it is caused by both too much and too little exposure. Orchids are not light-loving plants since they naturally grow in the shade of trees. Some of the most delicate orchids require completely indirect sunlight, or they will burn and yellow quickly.
However, most orchids still need enough indirect sunlight to grow. Most gardeners prefer screens and shade cloth to supply light that is not direct enough to burn.
3. Humidity Levels
Orchids love some humidity, but they are also prone to growing mold and bacteria on their leaves when there is too much moisture in the air. Add high humidity to high temperatures, and you will witness your orchid quickly yellowing and losing leaves.
The challenge is that indoor humidity levels vary from day to day and can change rapidly. You may set up a humidifier in the morning of a dry day and find your orchids far too humid by the evening.
You can use sensors that track the ambient humidity level and adjust humidifiers accordingly. Alternatively, you can use passive methods such as water trays which work better compared to constant humidification. Most orchids need 40 to 70% humidity; however, this varies by species.
4. Seasonal Changes
Since there are a number of common causes for orchids with yellow leaves, seasonal changes are hard on the plants. A change in the seasons naturally causes fluctuations in temperature, light, humidity, and more. If you are able to restore the correct conditions, a little yellowing from the change should not linger for long.
5. Potting Stress
Avoid changing your orchid’s pot more than necessary. Orchids like to be somewhat cramped in their surroundings. If you notice tightly packed roots that are green and healthy, you still do not need a larger pot yet. Dry roots will turn gray or white when it is time to actually repot.
Unwarranted potting often causes the leaves to yellow and die. Of course, waiting far too long for repotting will also stress the orchid. Time the reporting cycle is based on its growth, so it is crowded but has room to grow. Target to repot at least once every two years to refresh the broken down growing medium.
6. Nutrient Deficiency
Although orchids are not heavy feeders, they will yellow eventually if left for too long without feeding. First, you will see a lack of flowering and slow to stalled leaf growth. You can use an orchid-specific fertilizer and aim to only apply half the recommended dose at first.
Orchids often have difficulty absorbing iron when you add too much magnesium and nitrogen. This will lead to yellowing from the middle of the leaf outward. In this case, you are dealing with too much fertilizer as opposed to too little.
7. Exposure to Chemicals or Hard Water
One challenge that orchids do not respond to well is the type of tap water that you expose them to.
Some areas have hard water or water containing high amounts of chlorine. In these cases, your orchid plants may struggle to process these chemicals, causing the yellowing of their tips.
Hard water has high levels of magnesium and calcium, which can harm the plant’s ability to absorb essential micronutrients. This can cause nutrient deficiencies and leaf problems.
If you seem not to figure out why your orchid leaves are turning yellow, you can contact your local water inspector and request copies of the water testing results.
This will inform you of all the chemicals detected in the most recent test.
If the results show there is a problem, you have three alternatives: purchase a house filtering system, use rainwater, or purchase filtered water for your plants. Using rainwater is the most cost-effective, but it is illegal in some states. Therefore, check your state laws first.
8. Infection
Plant disease or infection can cause your orchid to turn yellow. Generally, diseases are more likely to cause yellow patches and spots on the leaves rather than the general yellowing of an entire leaf.
Here are some of the common infections and diseases that your orchid can encounter:
a) Fungal Leaf Spot
This infection is popular for causing yellow areas that begin on the bottom and underside of the leaves.
When left untreated, fungal leaf spots will cause the spots to become larger, turning black or brown.
For mild infections, you can spray or wipe the leaves with a fungicide. It is generally advised to get rid of all infected leaves and then treat the healthy ones.
b) Root Rot
If you come across any disease, it is likely to be root rot since it is most common.
Root rot is a fungal infection of the roots, which typically happens if you overwater, use a poorly draining medium, or a pot without drainage holes.
The primary issue with root rot is that it will spread over fast and kill your plant quickly. Therefore, if you notice yellowing leaves, check the roots of your orchid.
You will know your plant has root rot if the roots are black or brown, soft, and fragile.
If the plant has some healthy roots, it is possible to save the plant, but you need to use sharp, sterile scissors to get rid of all rotten roots.
c) Bacterial Brown Spot
If you see wet-looking brown or yellow spots on the leaves, chances are your orchid has the bacterial brown spot.
If your orchid is in a hot and humid area, this is more common. As it gets worse, it leads to the generalized yellowing of the leaves, which is indicative of the stress the plant is under.
The most effective treatment plan is to get rid of all infected parts of the leaves or the entire leaves. Always use sterile scissors.
After getting rid of the affected parts, you can spray a broad-spectrum antibacterial or fungicide to prevent the fungus spores from spreading to other unaffected parts of your plant.
9. Over-watering
As epiphytes, most species of orchids nestle in the roots and trunks of trees to keep their roots relatively dry. Adding a little too much water to your orchid’s pot can smother the roots and cause the yellowing of leaves within a few hours to days.
You may see leaf growth slow and stop first, or the yellow color may be the first sign of trouble. Save overwatered orchids by getting rid of the growing medium and trimming away any black and softened roots. Using a fast-draining pot with a loose soil medium made for cacti and orchids is necessary to prevent this common cause of yellowing.
10. Under-watering
If you are too worried to water your orchid when it needs watering, you will notice leaves getting soft and yellow. They will dry up, wrinkle, and the entire stem may soften or wilt. Orchids will not recover immediately from underwatering, so do not throw in the towel when the plant loses most or all of its leaves before recovering.
Make sure the humidity level remains steady and high during a re-watering phase to ensure the plant is not losing most of its water out into the air.
