Orchid stems turning white is one of the most challenging issues orchid enthusiasts face when growing orchids in their gardens. It takes a lot more time to get rid of this problem than it does for your orchid plant to get affected in the first place.Orchid Stem Turning White

Understanding the cause of the white coloration on your orchid is key to eliminating it. Here’s a helpful guide on why your orchid stem might be turning white and what you can do to stop it.

What Causes an Orchid Stem To Turn White?

An orchid stem to turn white is caused by watering the plant more than what it requires. In addition to this, it is also caused by fertilizer build-up taking place, and lastly, it can also be due to limited sunlight passing to the plant.

– Overwatering

When you water the plant more than the amount that it needs, this is a cause that the stem weakens and change its color. Except it is stated otherwise, it is vital to note that orchids do not in any way enjoy overwatering, and too much moisture can cause a lot of damage, especially around the orchid flower spike, the base of the plant, and the roots.

When you overwater, you end up with waterlogged soil, the perfect environment for mold growth, especially in areas with high humidity levels. In such a manner, you must know that the orchid plant is likely to suffer from mold infestation.

Increased humidity will promote the speedy growth of white mold on your plant, which will cause more damage to your orchid spike and other plants in your garden.Reasons for Orchid Stem Turning White

– Fertilizer Buildup

Most orchids thrive with little to no fertilizer application. However, when applying fertilizer, in a greater amount than the given, you must know that salt will begin to build up.

When your orchid is overfed, the soil experiences a mineral buildup, affecting the orchid flower spike and roots. Using tap water can also cause a buildup of minerals in the soil due to impurities, and this buildup can sometimes cause a white coloration on the surface of the soil and base of the stem.

– Limited Sunlight

Mold thrives in high humidity and moisture-rich environments, and this would exceed when the light source is weak as well. When you water your plant but do not give it enough light exposure, it could encourage a mold infestation, and this may thrive around the stem as well.

When this infestation spreads, you begin to see white patches on the stem, flower spike, and leaves of your plant. On the other hand, excessive exposure to direct sunlight will make orchid spike stems turn yellow.

How To Fix an Orchid Stem Turning White?

To fix your orchid stem turning white, you should ensure to keep moisture and humidity levels at the necessary range, avoid watering with tap water, regulate fertilizer application, expose your plant to ample sunlight, and boost air circulation in your garden and around your plant.Fixing Orchid Stem Turning White

– Regulate Moisture and Humidity Levels

White mold on orchids is caused by a fungus that thrives in moist or waterlogged soil. As a result, it’s best to avoid overwatering plants. Water plants about once a week to keep the soil dry enough that it doesn’t attract gnats but moist enough for the plant to survive.

Leave some time between your last and next watering, and this way, you will schedule the watering level and also the moisture that the soil holds.

When you water your plant, you automatically raise the humidity level around it. Orchids thrive in a humidity range of 40 to 70 percent, and knowing this, you must aim to keep it up because the drought can weaken the plant.

Anything lower than that will encourage the growth of mold. When you maintain the proper humidity levels, you can prevent mold from covering up the stems of your orchid and save it from root rot.

– Use Well-draining Pots

Always use a well-draining pot to plant your orchid, and most orchid plants grow well in baskets and mesh pots, allowing proper water drainage from the potting mix. You should also ensure you water your plants correctly and at the right time to prevent mold growth.

Watering your plants raises the humidity levels around them, and if you water it more than the given amount, with the holes in the pot, they will drain.

Suppose the infestation is more severe, and the white patches completely cover your plant soil and stem. In that case, you will need to extract your orchid from that pot, clean it up with some fungicide, remove rotting parts of the orchid, and replace the potting medium with a new one.

Consistently leaving water on the stem and orchid leaves can cause them to start turning yellow. It can encourage mold growth in your Phalaenopsis orchids. It is best to water your plants early in the morning before the sun or late in the evening. This way, the orchid plant absorbs just the right amount of moisture before sunlight comes to dry up the excesses.

Get pots that have holes at the bottom to allow water to pass through, knowing that mold thrives and spreads in moist, water-logged environments, it won’t survive in well-drained soils. You can also use a humidifier to monitor the humidity levels around your plant or substitute misting for water trays to raise the humidity levels without getting water on your plant.

It is very easy to regulate with water trays, as you can easily remove the plant pots from the trays when you notice that the humidity levels are too high.

– Improve Air Circulation

Suppose you expose your plant to moisture and high humidity. In that case, proper air conditioning is a nonnegotiable factor if you do not want white mold on the stems of your Phalaenopsis orchid.

When planting your orchids in the garden, ensure they are not blocked and covered up by other plants, thereby preventing ample air circulation around their stems and leaves. For this, you should ensure proper spacing between your Phalaenopsis orchid and companion plants when planting in the garden.

If indoors, you can encourage proper air circulation with a fan that blows toward the base of the plant. Using the right pots, like mesh and baskets, would promote air circulation. When adding potting mix, do not choke up the toots and leave it a little loose, so the roots also get some action, lowering the risk of mold infestation or spread.

– Regulate Fertilizer Application

Most orchids do not require fertilizers and do well independently if they get enough water and sunlight. However, if you need to fertilize your orchid when it is not doing so well, there are several things to check first. It is important to note that orchids have varying fertilizer requirements, and to give it the right type that it would thrive with, and of course, without being excessive.

While some might thrive with nitrogen-rich fertilizers, potassium-rich fertilizers can also work well for others. Most orchids prefer a balanced, organic fertilizer. Anything other than this can cause the deposition of harmful chemicals and materials on the body of the orchid and cause it to turn yellow.

Excessive fertilization is what can cause the buildup of these minerals, which can sometimes appear as a white powder after the moisture has dried up.

– Using Clean Water

Using any other type of water except distilled water can cause a lot of harm to your orchid. For one, tap water contains many chemicals that can cause soil buildup and deposit minerals and chemical substances in large amounts in the soil and the body of your plant.

Tap water also has high levels of pathogens, this would also including bacteria and fungal pathogens. The white mold on plants is caused by a fungus known as Sclerotinia sclerotiorum, and it can survive in your plant’s soil for a very long time, and as you give it contaminated water, it will thrive.

– Change the Soil Completely

Once you start to notice white mold on the stem of your plants, rest assured that the fungi causing this mold are already present in the soil and spreading fast to different parts of the plant. When not handled and taken care of, it spreads to other plants in your garden. Cleaning up the plant is sometimes not enough to control it, and for this, you will need to bring in fresh potting mix in a fresh pot.

Place the plant where it can get ample air circulation to prevent a recurrence. Add a layer of dry soil or orchid potting mix to help control white mold growth and spread. Please do not do this during the blooming cycle, as it can cause parts of the plants to start turning brown or dry out.

– Using Fungicides

The first thing to note is how much the orchid is infected. If it is just white patches around the stem, some leaves, and the soil, you can try out any effective measures like using the right fungicides.Fungicides for Orchid

Neem oil is a natural insecticide that you can use to treat fungus infestations like white mold. It helps defeat white mold and ward off other unwanted pests. Combine half a liter of distilled water with a few drops of organic neem oil in two parts to one and add into a spray bottle.

Apply the new mixture to the infected plant for several days until your plant is rid of the white mold. If the infestation is aggressive and has done a lot of damage, you can mix neem oil with some water and mouthwash. Soap also works well to emulsify the mixture. Once your mixture is ready, apply it to the plant by spraying it from the base of the plant upward and onto the affected soil around the plant.

You should note that certain orchids, like Miltonia and Masdevallia, are sensitive to neem and other horticultural-based oils. Before adding them to the mix, test or research your plants’ reactions. On the other hand, you can also use diatomaceous earth, or DE, as a fungicide, which is an excellent way to kill fungus gnats. It is a natural pest and insect deterrent and the great thing about it is that it isn’t toxic to plants.

– Diatomaceous Earth

A more bio friendly option will be using diatomaceous earth, which is the safest for plants and the affected soil. Let the soil dry out, and then sprinkle a thin layer of the powder on the surface of the affected soil. It will not only keep insect pests away but will also help treat and prevent a white mold situation on your orchid.

This substance, made from fossilized aquatic organisms known as diatoms, is a natural fungicide and has proven very effective in treating mold. It is a natural pest and insect repellant, making it a top choice for every gardener and orchid enthusiast. They control the spread of the white mold and destroy it in the soil, causing it to dry out completely.Orchid Stem Turning White Details

– Using Simple Chemicals

You can treat your soil with dilute concentrations of hydrogen peroxide to eliminate white mold. Treatment with hydrogen peroxide is very effective, and the materials needed for the treatment can be easily obtained over the counter. Mix three percent hydrogen peroxide with water in a ratio of 3:1 and spray the mixture onto the mold-infected stem of your orchid.

You can mix in some Epsom salt for more effectiveness, as the sulfate deters and controls fungus infestations. A simple Epsom salt and water solution will do the trick, especially for severe white mold infestation problems.

Although, like with many other options that have to do with chemical compounds, you should do a patch test to check if Epsom salt is safe for your plants. Other harmful chemicals will cause the plant to start turning yellow based on the lacking nutrient.


When it comes down to treating that white infestation on the stem of your orchids, if you’ve been dealing with fungus mold for a while, you’ll understand how annoying they can become over time, so let’s briefly look at these helpful orchid care tips for white mold.

  • If you notice white coloration covering your stems, try poking them with a stick. If it moves or flies, then it’s a mealybug. If it doesn’t and appears powdery, then you have white mold.
  • Use well-draining pots and porous potting mix to avoid waterlogged or soggy soil when planting orchids.
  • Always do a patch test on your plants to check if the chemical compounds you want to use are safe before application.

Now you know so well how to have healthy orchid that is as good as saved from its white mold infections, so it’s always easier and better to get rid of them early. This article helps you know some of the best ways to eliminate this annoying infestation.

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