White Spots on Orchid Leaves (Causes and Treatments)

White spots on orchid leaves mean that something is going on with your beloved plant.

This means it is important to immediately focus on identifying the cause. Only then will you be able to apply any treatment.

Why are there white spots on your orchid leaves? Powdery mildew, overwatering and low humidity are among the most common causes of these white spots.

In addition to moisture issues, sunburn, pests and viral diseases can likewise be the cause.

Because these all vary significantly, it is important to narrow down the root cause before starting any treatment.

Why are there White Spots on Orchid Leaves?

Improper Watering

If you notice white spots on orchid leaves or entire leaves turning white, consider checking the plant’s roots.

Orchids like being soaked in water to allow their roots to absorb the moisture the plant needs.

But in general, they prefer staying dry.

That’s because most orchids are epiphytes.

This means that the roots of the plant are different from those of other plants.

Instead of staying under the ground, most orchid roots are used to cling on larger trees, barks, trunks of plants.

Because of this, their roots have evolved to become very efficient at absorbing water.

Thus, you do not need to water them daily or every other day. Doing so puts the plant in danger as overwatering increases the risk of root rot.

And one of the warning signs you’ll see of overwatering are white spots on its leaves.

 

Lack of Humidity

Another potential cause of white spots on orchid leaves is low humidity.

Note that both humidity and watering are closely related as they’re both associated with moisture.

However, humidity is about the moisture in the air.

Thus, it affects the leaves more.

In contrast, watering involves giving the roots moisture.

That said, high humidity reduces the need to water while low humidity means you need to keep the plant better hydrated.

So, both humidity and watering still affect one another.

In case you’ve made sure that there is no overwatering and you’re still seeing white spots on your orchid’s leaves, consider checking humidity.

Low humidity causes the leaves to get dry.

And once the orchid’s foliage starts drying out, you’ll see white spots with dark borders on its leaves.

 

Excess Heat or Cold

Orchids like moderate temperatures. And you may see white spots develop if you leave the plant in too hot or too cold an environment.

In excess heat and lots of sunlight, the leaves can quickly dry up.

This makes it susceptible to sunburn as well if kept under too much intense sunlight.

As a result, you’ll start seeing sunburn spots in the form of white dots with a darker outline around them.

Similarly, if there are water spots on the leaves, the sunlight will get magnified through the water spots and results in these white spots as well.

Thus, if you’ve checked and are sure that overwatering and low humidity are neither the problems, take note of how much sunshine your orchid gets during the day.

If it gets the brunt of direct sunlight during the middle of the day, the excess heat can be the cause of the white spots on its leaves.

Therefore, move the plant to somewhere that’s bright but with indirect or filtered light.

Another possibility is if you keep your orchid in cold temperature.

Winters are bad times of orchids. And leaving the plant in temperatures of 30 degrees Fahrenheit or below will put it at risk of frostbite.

When frostbite strikes your orchid, you’ll see white spots develop on its leaves.

This is why you want to avoid cold breezes, drafts and freezing air from coming into contact with the plant.

As such, keep your orchid indoors and away from open windows during the winter.

 

Powdery Mildew

One of the most common causes of white spots on orchid leaves is powdery mildew.

This is a type of fungal infection, more specifically a mold.

And it will appear are small white spots initially.

But if not immediately treated, the white spots will spread in clusters and form patches.

This will continue to develop until entire leaves are covered by a white layer.

What’s unique about powdery mildew is its appearance. As such, it is easy to tell once you see it.

Unlike other white spots on your orchid, powdery mildew will look like powder has been sprinkled on the leaves.

But don’t try to scrape them off. Nor is it a good idea to mist the plant.

Why?

Powdery mildew spreads easily through the air.

They do so via spores that easily float into the air.

Therefore, be careful about letting gusts of wind or the breeze of electric fans blow on a plant inflicted with this fungus.

It also means that it is easy for other nearby houseplants to get contaminated.

So, immediately isolate any affected plants.

 

Mealybugs

Orchids are susceptible to pests just as other houseplants. But when it comes to white spots on its leaves, the obvious culprit here would be mealybugs.

These are tiny cotton-like creatures that are white in color.

Thus, you’ll notice them as miniscule white spots on the leaves and other parts of your orchid.

In addition to the pests themselves, mealybugs also produce sticky secretions which help you identify the problem.

Unfortunately, because mealybugs grow in population very quickly, it is important to immediately treat the plant even if you see just a few bugs present.

 

Diseases

One of the more dangerous causes of white spots on orchid leaves is viral diseases. Viruses are troublesome because they can be hard to identify.

What’s worse is that there’s no cure for them.

Additionally, there are quite a few viral infections that affect orchids. Some but not all 20 can cause white spots to appear.

As such, the best thing to do is try to prevent these viruses from happening.

In many cases, viruses come from the soil that’s used for your plant. But it can also happen if you use unsterilized tools.

This is why it is very important to clean your blades with rubbing alcohol or bleach before cutting any of the stems of the plant.

 

How to Treat White Spots on Orchid Leaves

Fixing Overwatering

Overwatering is dangerous because of its consequences. It can lead to root rot which can be fatal to your lovely orchid if not treated in time.

As such, prevention is best when it comes to too much moisture.

Ideally, orchids only need watering every 1-2 weeks. The best way to tell when the plant needs watering is to check its roots.

Its roots have a thin layer called velamen. This layering makes it easy to tell if your orchid needs watering or not.

When the velamen looks dry, it will look white or silver in color. In contrast, a well-hydrated orchid will have nice looking healthy green velamen.

If you keep your orchid in moss or soil, wait until the moss dries up or the soil almost completely dries. This will be your main indicator when to water the plant.

Do not let your orchid’s root stay consistently moist. This is a recipe for root rot.

While orchids only need occasional watering, they do like getting soaked when you water them.

Thus, the best way to ensure that the plant gets proper hydration is to dunk the pot or your orchids roots into a sink filled with water. You can likewise do this in a bucket filled with water.

You can leave your orchid floating in the water for a little bit.

This will allow the roots to absorb all the moisture it wants. They key is to water it thoroughly.

Don’t forget to allow the plant to drain afterwards.

Often, the biggest mistakes when watering orchids include:

  • Watering the plant too frequently
  • watering it late in the day when there isn’t much sun
  • Not checking the roots, moss or soil before adding more water

Finally, in case your orchid has white spots, your goal is fix the problem. To do so,

Take the plant out of its pot or moss. Then clear the roots of any debris, dirt and soil. If there are any damaged or affected leaves, remove them.

Then let the roots dry. They will dry faster outside of the soil since they are exposed to air.

Ideally, choose a secure spot to leave the plant where it gets good sunlight that’s not direct, enough air circulation and warm temperature.

These factors will help speed up the drying process.

Once the roots have dried, repot the plant in new, fresh soil. Note that you do not need to use soil for your orchid as most are epiphytes.

 

Avoiding Underwatering

In addition to overwatering, you want to be careful about underwatering as well.

The issue here is that the change in temperature especially during the summer can speed up the drying process.

If your orchid is placed in intense light, you also increase its susceptibility to sunburn.

While underwatering is not as big an issue as overwatering, it still can become a problem if you don’t water the plant enough.

As mentioned above, orchids do not need daily watering. Instead allow the soil to dry between waterings.

That said, make sure to saturate the roots with moisture by watering thoroughly when you do water the plant.

The best way to do this is to immerse the roots or the container in water for 10 to 20 minutes. This will let the roots absorb the moisture they want.

After that, allow the excess moisture to drain.

 

Treating Powdery Mildew

Powdery mildew thrives in damp or moist conditions. Therefore, you do not want to keep your orchid overwatered.

Wetting the leaves and keeping the soil consistently moist increase the risk of powdery mildew.

And once you notice these white powder-like spots or patches on your orchid’s leaves, it is important to start treatment immediately.

The first step is to isolate the affected plant.

This will prevent the powdery mildew’s spores from spreading to other nearby houseplants.

Keep your orchid somewhere with plenty of sunlight as long as it is not direct. Choose a warm spot with good ventilation.

These features will help the plant dry faster.

In doing so, it prevents the mildew from developing or spreading.

In case there are only a few leaves affected, then you can just prune the leaves. This will quickly get rid of the powdery mildew.

Another option is to use a fungicide for treating powdery mildew. These are available in nurseries and other plant stores.

You can likewise create your own DIY powdery mildew solution at home by combining 1 tablespoon of baking soda with ½ teaspoon of liquid soap per 1 gallon of water.

 

Get Rid of Mealybugs

Mealybugs are bothersome pests that look like white spots on orchid leaves.

You can easily identify them using a magnifying glass if you see white hairy spots. These bugs will look like they’re covered with cotton.

Although, without a magnifying glass, they’ll look like tiny white specks at best.

That said, they grow quickly in number. And that’s when they can cause serious damage as they suck on your plant’s sap.

The good news is that there are many ways to get rid of mealybugs.

The bad news is that you need to act as early as possible.

Once they grow in number and become an infestation, it is much harder to get rid of all of them. The problem here is that if you don’t eradicate all of them, you’ll see new mealybugs pop out within a few days.

So, make sure to get rid of all the adults, larvae and eggs.

My go to treatment for mealybugs is to spray them off with water. I prefer doing this to get rid of as much as I can in the shortest amount of time.

There are other methods as well. But some are tedious as you  need to dry to get the bugs one by one or soap down the leaves one at a time.

You can use a shower head or garden hose to spray off the bugs.

The stream of water will dislodge the pests. Although, you probably won’t be able to get all of them in one spraying.

Therefore, repeat every 3-4 days until you don’t see any more mealybugs.

Another option is to use neem oil and dilute with water. Then spray the leaves.

You can likewise use insecticidal soap spray instead.

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