So why are my orchid leaves turning yellow?
Or why do orchid leaves turn yellow?
Or how to save a dying orchid?
It’s really all one and the same thing.
Any healthy plant, including orchids, will occasionally experience some leaf yellowing. In the case of orchids, it’s particularly the lower leaves that yellow. Nevertheless, if leaves are yellowing, it could mean there’s a problem.
It’s not overly difficult to figure out exactly why your orchid has a problem with yellowing leaves. In this article, we’ll look at what is arguably the 10 major causes for leaf yellowing in orchids. We’ll also assess what solutions are available.
Why Are My Orchid’s Leaves Turning Yellow?
Here are the 10 main reasons for orchid leaves turning yellow:
- Direct and excessive sunlight
- Temperatures too low
- Temperatures too high
- Orchid overwatered
- Foliage naturally dying
- Sudden change in environmental conditions or environment in general
- Hard water and unwanted chemicals
- Too much fertilizer
- Nutrient deficiency
- Infection – fungal or bacterial
Problem #1. Direct and Excessive Sunlight
Typically, in their natural environment, orchids will grow in rain forests and out of the way of direct sunlight. Normally, orchids may only get a couple of hours direct sunlight each day. Many get no direct sunlight at all.
This means that you’ll want to try to emulate these conditions in your home. While your orchid will enjoy plenty of light, it will not enjoy being subjected to lots of direct sunlight.
During the summer months, an ideal window for an indoor orchid will be north or east facing.
In the winter you’ll probably want to relocate your orchids to an east- or south-facing window. This way your orchids will still receive enough light.
Problem #2. Temperatures Too Low
For the most part, indoor orchids (‘indoor’ meaning for cooler climates since ‘indoor’ orchids will be outdoor orchids in warmer climes) do best in temperatures that range between 60-80 °F (15-27 °C).
And for most homes, that’s also ideal. Making many orchids ideal as houseplants.
If your orchids are subjected to temperatures that regularly drop below that of 60°F (15°C) your plants will become stressed.
The leaves will become progressively yellow and they may also begin to drop off.
The leaves may slowly turn black or brown, and then the plant will die.
If you need one, get yourself a room thermometer. That way you can be absolutely certain that if your orchid or orchids are suffering from leaf yellowing it is or it is not caused by excessive temperature variation.
Better still, if your room thermometer records the highest and lowest temperatures as well as the current temperature then you are well set to know for sure.
Problem #3. Temperatures Too High
Many orchids are natural inhabitants of tropical forest locations. But this does not mean they love extremes in temperature.
Rather, orchids grow best under the tree canopy. And under the tree canopy, the temperatures are generally quite moderate.
Temperatures below the tree canopy are fairly steady and humidity levels are very high. Nighttime temperatures experience a slight dip in temperature.
Orchids in your home will greatly benefit from something of a ‘mimic’ of this natural environment.
If temperatures in your home frequently rise about 80 °F (27 °C) then your orchids will become stressed because that’s too hot.
Leaves will yellow because of this stress. The leaves will drop off and the plant will eventually perish.
Problem #4. Orchid Gets Too Much Water
Overwatering orchids are the most commonplace reason that the leaves begin to yellow. Overwatering will result in rotting of the roots and eventual root death.
That means your orchid or orchids cannot absorb water and they cannot take in nutrients.
For most people, we have a tendency to overwater houseplants rather than underwater. Normal, of course, because we feel that giving indoor plants ‘enough’ water will keep them happy and vigorous in terms of growth.
Orchids, in particular, do not need much water. Making it ever so easy to persistently overwater.
Water your orchids only when the potting medium is dry.
How do you know the potting medium is dry?
Stick your fingers into it and see if it’s moist, dry, or something else.
Some people can tell if their houseplants are dry simply by picking them up (in the pot) and getting a sense of the weight. Not everyone is able to do this and it does take experience.
But if you do want to take this route one way to achieve it is to use kitchen scales. This way you’ll know for sure when your orchid/s need water and when they do not need water.
I tend to prefer to underwater orchids rather than overwater. Orchids generally have a far better tolerance for too little water than too much.
Problem #5. Foliage Naturally Dying
Obviously, this is not a problem other than it is a little unsightly to have orchids with yellow leaves.
It’s normal for an orchid’s lowermost leaves to die from time to time.
Usually, that will occur when the orchid has new leaves coming through or perhaps it’s because there’s a new flower spike.
Orchids want to prioritize the fresh, new growth. To do so they ‘relinquish’ the oldest growth in favor of the new.
So if the lowest leaves on your orchid are starting to yellow, nothing to worry about. Just let it be. Given a bit of time, the leaves will drop off themselves.
It’s best not to manually remove yellowing leaves. Doing so makes the plant more susceptible to disease. Just try to be patient and allow natural processes to occur.
If the leaves are very yellow but still not falling off naturally, by all means, use a sharp sterile knife to put them out of their misery. You can also treat the wound with a diluted solution of hydrogen peroxide as this will reduce the infection risk.
Problem #6. Sudden Change In Environmental Conditions or Environment
If the environment where your orchid is suddenly changed for whatever reason in terms of temperature or lighting the orchid can undergo some stress. The same can occur if your orchid is moved to a new location.
The response can be to drop blooms or leaves. In a less severe scenario, the leaves will start to yellow.
If you’ve just bought an orchid and this sort of thing occurs, no need to panic. Over time the new orchid will get used to its new home, provided that its new home offers healthy growing conditions.
If you’ve moved your orchid from one window to another and it – the orchid – is starting to experience stress, that’s nothing to worry about either. Again, though, it’s nothing to worry about if you’re aware of the conditions your orchid needs to thrive.
By reading through this article you’ll become familiar with indoor orchid needs for a healthy lifestyle.
Problem #7. Hard Water and Unwanted Chemicals
Tap water is not always ideal for indoor orchids.
If your tap water is particularly hard or if the water is treated with excessive amounts of chlorine, chloramine, or fluoride, the leaves on your orchid can start to yellow – or at least the leaf tips will very likely become yellow.
Hard water consists of high levels of magnesium and calcium. High levels of magnesium and calcium can cause problems for orchids in terms of not being able to take up other essential nutrients through the root system.
This leads to a nutrient deficiency which will demonstrate itself in various problems, not least of which will be leaf yellowing.
If you suspect that tap water is the culprit for your orchid’s leaves turning yellow, you might want to start using rainwater or filtered water instead of tap water.
Problem #8. Too Much Fertilizer
Adding too much fertilizer to orchids is somewhat akin to the problem of overwatering. We tend to have a concept of adding more is better than adding less. In fact, it’s better to be the other way around – in terms of watering orchids and also in terms of fertilizing orchids.
Fact is, too much fertilizing or orchids is much worse than too little fertilizing of orchids.
Adding excessive nutrients – too much zinc, phosphorus, manganese, copper, calcium – that can stop your orchids from taking up iron in the root system. This will lead to iron deficiency which makes itself known through yellowing of the leaves – also referred to as ‘chlorosis’.
Orchids are, on the whole, light feeders. They need dilute and infrequent fertilizer concentrations.
Best thing to do is to get a dedicated orchid plant fertilizer or to dilute your usual houseplant fertilizer to a half or a quarter strength.
Investing in a dedicated orchid fertilizer takes any guesswork out of the equation.
Fertilize once every one or two weeks throughout the vegetative stage. When your orchid is in bloom stop fertilizing completely. Once the blooms are over, begin fertilizing once more.
Further good practice is to water one time without any fertilizer then water the next with fertilizer added to the water. This stops any toxic buildup of nutrient salts occurring within the growing medium.
Because the majority of orchids are bought when they are blooming, over the first couple of months at least of the orchid being in your home avoid fertilizing.
After the final blooms have been and gone you can begin fertilizing.
Problem #9. Nutrient Deficiency
Some people get an orchid and fail to fertilize. For sure, the potting medium will very likely have some fertilizer in it already. But over time that supply of nutrients will run out.
In terms of nutrient deficiency of orchids and yellowing of leaves because of nutrient deficiency, the main nutrients that are lacking here will be nitrogen, manganese, zinc, and iron.
It’s easy enough to remedy this situation: Invest in a dedicated orchid fertilizer.
Problem #10. Orchid Disease Infection
Yellow leaves can be caused by some sort of orchid infection, be that a virus, a fungal infection, or a bacterial infection.
Though orchid disease infection tends to show up as yellow areas on the leaves it can also result in a generalized leaf yellowing.
In orchids, this is the most commonplace disease. It occurs when orchids are overwatered or if the orchid is in a growing medium that is very poor draining. Or, it could be that the pot where your orchid is has no holes in the base for drainage.
An otherwise healthy orchid can perish fast when root rot occurs.
That said, if your orchid does start to develop yellow leaves among the initial things to check is the roots.
If your orchid pot is of the transparent kind you can look through the pot to assess the roots. If it’s not a transparent pot it will be necessary to inspect the roots by taking the orchid out of the pot.
Root rot shows itself as the roots being black or brown. They are also very fragile and soft.
If your orchid does still have some healthy root growth there’s still time to do something about it. All of the rotten roots should be removed using a sharp sterile knife or a pair of sharp secateurs.
Your orchid can then be repotted in a medium that is quick to drain – pine bark is ideal for fast drainage. Use a transparent orchid pot that has lots of drainage holes in the base.
Last thing, only water the orchid when the potting medium is dry to the touch.
Fungal Leaf Spot
Fungal leaf spot is another commonplace orchid infection that demonstrates itself by way of yellowing leaves. The yellowing begins on the leaf underside. The yellowing begins as spots and if the fungal leaf spot is untreated the spots become larger and will start to turn black or brown.
If your orchid is not badly infected by fungal leaf spot you can attempt to treat it either by wiping or spraying the affected leaves with an appropriate fungicide.
Either this or a better approach to take is to remove any leaves that have become infected. Dispose of those leaves. Then treat remaining leaves with the fungicide to remove any spores of the disease.
Bacterial Brown Spot
Bacterial brown spot demonstrates itself through wet-looking, irregular yellow or brown spots on the orchid leaves. It’s a far more common problem on orchids that are situated where conditions are hot and humid.
With worsening of the disease, the leaves can become yellowed which shows signs of distress.
Remove any leaves that infected or at least remove parts of the infected leaves if the disease is not so severe.
Removal should be carried out with a sterile blade or sterile scissors. Cut into the healthy leaf tissue. This will help to avoid spreading the bacterial brown spot disease.
After removing the infected parts or entire leaves you can use a broad-spectrum fungicide or bacterial spray. Either that or use a hydrogen peroxide solution that has a 3% dilution and rub that onto any infected areas of your orchid.
Here’s a video about how to remedy yellowing orchid leaves) or how to figure out what’s causing orchid leaves to turn yellow) brought to us by orchid specialist: Miss Orchid.