White mold in garden

As far as plant diseases go, there are none more annoying, frustrating, and hair-pulling than fungus issues. Whether you’re growing microgreens, houseplants, or veggies, plant fungus like powdery mildew can absolutely ruin your plants.

Here’s an example of a classic type of plant fungus, powdery mildew:

Powdery mildew infesting a plant’s leaves. source

Here’s a simple rule to detect plant fungus: If your plant has started showing signs of unusual spotting or has growth on it that is a different color than the plant, it probably has some kind of fungus.

There are a variety of ways to treat fungal problems, fungicides being one of the most common. But, harsh sprays that contain chemicals are sometimes not the ideal way to treat plant problems, especially if they’re inside your home.

If you don’t want to use fungicides, you should consider this simple remedy: baking soda.

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Using Baking Soda To Prevent and Treat Plant Fungus

Before we get into the recipe, it’s important to mention that this remedy is best used as a preventative measure rather than a full treatment. After your plants have been covered in mildew, it’s very difficult to completely remove it. Use this recipe weekly on plants that you know are susceptible to mildew and fungus issues, or if you experience high humidity (which fungus loves).

  1. One gallon of water
  2. One half teaspoon of liquid soap
  3. One tablespoon of baking soda

Make sure you use this mixture quickly and do not store it — it doesn’t keep well.

The liquid soap helps the mixture stick to the leaves and stems of your plant, so be careful not to use too harsh a soap. Some gardeners, myself included, have reported accidentally burning the leaves of their plants with this spray. To avoid burning:

  1. Do not apply the mixture on plants exposed to full sun.
  2. Water your plants a few days before application.
  3. Test the mixture on a small section of your plant before you spray the entire plant.

I’ve also heard gardeners recommend adding horticultural oil to this mixture, because the oil will stick to the leaves and suffocate the fungus. If you want to test this out, go ahead and let me know in the comments if this works for you!

Still Having Plant Fungus Problems?

Like I mentioned earlier, if you are having a hard time getting rid of plant fungus with this baking soda mixture, it’s probably because you have too much on your plant already. It’s best used as a preventative measure. You might need to try more aggressive measures, like the ones found in my guide to treating powdery mildew.

You can also try treating your plants with milk — yes, milk — and seeing if that has any effect. It’s one of the stranger remedies I’ve heard of, but I’ve tried it and it actually does work for me.

Baking soda, soap, and water is one of the safer ways to treat plant fungus issues, especially if the affected plants are inside your home. You really don’t want to be spraying fungicide all over the inside of your home if you can avoid it!

Do you have any remedies you’d like to share? Please let me know in the comments below.

The Green Thumbs Behind This Article:
Kevin Espiritu
Clarisa Teodoro
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What Is White Mold and Is It Dangerous?

Mold Restoration June 20, 2018

White mold is a term that applies to many species of mold which can grow in homes. And, like any other mold, it may compromise your property and health if you don’t deal with it. Read on to learn what white mold is and how it can affect your health.

What is White Mold?

White mold is not a specific type of mold – many species of mold may appear white. The species of white mold commonly found in homes are aspergillus, cladosporium, and penicillum. All these molds may also appear gray, green, black or other tints. Moreover, all molds thrive in moist areas where a food source like wood is present.

Generally, it’s not necessary to determine the type of mold you have in your home – all molds have the same negative effects.

Some molds may appear white in their early stages of development. Later, these molds may change color after producing spores. Yet, many molds appear white regardless of age because their spores are not pigmented. The lack of spore pigmentation is caused by the type of material it’s growing on.

Also, white mold appears as powdery and may blend in with the materials it’s growing on, which makes it hard to tell that it’s actually mold.

White Mold vs Mildew and Efflorescence

Sometimes, people confuse white mold with mildew, which may also have a white appearance. However, mildew rarely grows on surfaces other than plants and doesn’t destroy materials. White mold, on the other hand, penetrates the surface of porous materials like wood or drywall and can ruin them.

It’s also common for people to confuse white mold with a substance called efflorescence. It’s a type of salt deposit caused by salty water which seeps through concrete, brick or stone. When the water evaporates, it leaves behind a white crystalline substance that looks similar to white mold.

Unlike white mold though, efflorescence does not pose any health risks and won’t grow or spread.

To tell whether a substance is white mold or efflorescence, just look at the affected surface. If it’s masonry, it’s efflorescence. Also, put some of it into a drop of water and if it dissolves, it’s not mold. Lastly, squeeze some of the substance between your fingers and if it breaks into fine powder, it’s efflorescence.

Is White Mold Dangerous?

All types of mold, including white mold can cause health problems. White mold should be removed as soon as possible to avoid health risks and structural damage. Even milder forms of white mold can endanger your health.

Since some people don’t realize that white mold is mold, it may put them at risk for extended periods. The symptoms induced by white mold include allergic reactions, respiratory infections, eye irritations, dizziness, nausea, headaches, and even depression.

If you suspect you or a family member has been affected by mold exposure, consult a doctor and have the mold removed immediately.

White mold is just one type of mold that can invade your home. Check out information about black mold, and how to remove mold from your home. For mold removal and water damage repair services, contact your local PuroClean office.

Known as the “Paramedics of Property Damage®,” PuroClean provides fire and smoke damage remediation, water damage remediation, flood water removal, mold removal, and biohazard cleanup to commercial and residential customers. Founded in 2001, PuroClean has a comprehensive network of 300-plus franchise offices across North America. PuroClean technicians are thoroughly screened, insured, and trained in utilizing the latest in mitigation technology and procedures, while operating under a strict code of ethics. Each PuroClean office is independently owned and operated. For franchise information, visit www.puroclean.com/franchise.

Sclerotinia Stem Rot (White Mold) in Soybean: What to Look For

Figure 1. (Left) On the ground see the tan apothecia (fruiting structure) for Sclerotinia, the source of spores for Sclerotinia stem rot (white mold). (Photo by Jaime Willbur, University of Wisconsin)
Figure 2. (Right) Symptoms of Sclerotinia stem rot on soybean stems. Note white color of tissue (bleaching) and the cottony mycelium on stem. (Photo by Loren Giesler)

Over the past couple weeks there have been questions on what to look for when scouting for signs of white mold in soybean. This article is intended to show the differences in the apothecia and other common fungi observed in soybean fields. Apothecia (Figure 1) are the mushroom like fruiting structures formed by Sclerotinia sclerotiorum, the causal agent of white mold. These structures release the spores that start the disease cycle.

White mold or Sclerotinia stem rot is a disease that starts earlier in the season during flowering. The actual infection occurs on the senescing flower which is used by the fungus as a food source. Infections in soybean typically start at a node. You can tell when the infection occurred based on how high up the plant the stem lesions and fungal growth are. The much warmer temperatures during flowering this year should result in much lower or no disease development in many portions of the state where there was significant disease the past three years. When temperatures are over 85°F during flowering, there is a much lower risk of development.

Typically, plant symptoms will not appear until the fungus has progressed to the point that plants are dying. In the field you will notice individual or small pockets of dead or dying plants. Upon close inspection you will see a white cottony fungal growth on the stems (Figure 2). You may also see dark black bodies (sclerotia) of the fungus on the stems. If it is drier and plants are dead, the stems will be very light (bleached) in color. When dead stems are split, often you will see the sclerotia inside. Keep in mind that the disease will not spread much if temperatures are in the 90s. The optimum temperature for growth of this fungus is 75°F.

Figure 3. Bird’s nest fungus. Note two seed-like bodies (peridioles) on the left. (Photo by Jaime Willbur, University of Wisconsin)Figure 4. Mycelial growth on the soil surface which is not associated with white mold. This is a fungus that is decomposing crop residue. (Photo by John Bernt, Country Partners Coop)

Similar Looking Fungi Not Associated with Soybean Diseases

Several common fungi produce growth and fruiting structures in fields as a result of natural decomposition of crop residue. This is especially true in fields with higher yields and larger amounts of residue. The bird’s nest fungus (Figure 3) and other small fungal fruiting structures are often mistaken for the apothecia of Sclerotinia. In addition, this time of year you can see white mycelial growth on soil (Figure 4), a natural decomposing fungi that may be thought of as “white mold.” Neither of these fungi are associated with disease. At times the white mycelium can grow onto the base of the soybean plant, but the plants will be healthy with no adverse effects.


If you are uncertain of what’s causing damage in your field, I encourage you to have a suspect sample identified by UNL’s Plant & Pest Diagnostic Clinic. (See for information on submitting samples.)

More information on these and other soybean diseases can be found in the Plant Disease section of CropWatch.unl.edu.

Moldy Soil

A great question came in this week to Ask Gardenerd:

“My garden soil has this yucky whitish hue to it. I am assuming it is a type of mold (I do think I have been overwatering). When I took it out of the bags (10 bags)a few months ago, it did have a few “moldy”looking spots (I took back some of the bags but they told me it was”normal”). Is there any way I can salvage this soil?”

I understand your concern, but the folks at the nursery are correct. The mold in your soil is totally normal. Most good quality soil amendments have beneficial micro-organisms present that help your soils “social life” so to speak. Here is what Kellogg has to say about it (they make my favorite soil amendments).

“The mold you see, although it may look alarming, is harmless and an indication that the material is rich in plant nutrients. The white fuzzy “mold” is actually from a mycelium fungus which is a naturally occurring beneficial soil fungus that grows in rich organic matter.

Simply place all the soil from the bag in a wheelbarrow or in pile on the ground and stir it up with a rake or shovel. The white fuzzy stuff will mostly vanish from sight. It will not harm your plants- it will actually help feed them. This type of fungus helps break down the good stuff like worm castings, kelp meal, bat guano and chicken manure making these available to plant roots.

These pores of the fungi are present in the compost all the time. This is normal and good. Certain combinations of temperature, moisture, air and organic material can make the fungi grow unusually fast which is apparently what happened to the bag at your house. Not to worry. Simply work the compost into your garden soil as instructed on the package and the plants in your garden will love it.“

If you are seeing mold or mushrooms in your garden where this soil is located, you may be overwatering. You can cut back on watering and that should help eliminate the visual signs of mold and mushrooms. You can also keep loosening the surface layer of soil around your plants to help air flow properly. But don’t worry, it’s totally okay to have this friendly fungus co-habitating with your plants.

Thanks for writing in!

What Is White Mold : How To Treat White Mold On Plants

Even experienced gardeners can get a disease or pathogen in the garden that they can’t identify or treat. White mold is one of those sneaky fungal diseases that can strike quietly and take over a planting bed without any notice. What is white mold? We’ll explore some white mold information and tips on how to identify and treat this quiet but deadly disease.

White Mold Information

Fungal diseases come in all shapes and sizes, but white mold is one of the more common varieties that affects food and flower crops. In fact, it affects more than 400 species of plants, with the broadest impact on economic crops. The symptoms of white mold can mimic many types of disease. It is not until you get up close and identify its mycelia that a confirmed diagnosis can be made. And by then it is too late for that plant, and its neighbors may also be infected.

Garden vegetables and many flowering annual plants are often affected by white mold. What is white mold? The symptoms of white mold include leaf die off, stem wilt, and white fluffy growth on affected plant material. This develops into sclerotia, black hard, pencil size structures on diseased plant parts. Over time, plant death occurs.

White mold is most prevalent in warm, moist conditions, especially when plants are overcrowded and have not been rotated. Sclerotia overwinter in soil and reproduce in mild, wet weather. The sclerotia have been known to live in soil for up to 5 years. The diseased spores can even blow in from a neighboring field.

Other names for the disease are white canker, watery soft rot, timber rot, damping off, pink rot wilt, crown rot and several other descriptive names.

How to Treat White Mold

This fungal disease can be quite difficult to treat, as symptoms of white mold initially mimic many other plant problems. Once white mold is in a garden site, it usually shows up annually, due to the spore’s ability to overwinter in fallen plant debris and soil.

Flowers and damaged plant tissue are often the first to be colonized by the disease. Spores spread not only by wind, but also through insect activity and rain splash. Plant material left behind from previous year’s harvest are often the culprits of initial contaminants.

There is no approved white mold treatment. Once a plant has the disease, you can try to prune the plant to below infected material and apply a fungicide. However, there is very limited success with this method unless the disease is caught very early. It is best to remove the plant and destroy it.

Preventing White Mold

Since there is no effective white mold treatment, it is best to try to prevent the disease. Experts on how to treat white mold suggest crop rotation and cleaning up previous season plant debris. Use plants that grow upright rather than crawl on the ground and ensure plenty of air circulation. Water in the morning deeply with soaker hoses or drip irrigation. Do not compost infected plants, as most compost situations will not heat up sufficiently to kill the sclerotia.

Instead of trying to come up with effective white mold treatment, use resistant plants. Some of these are:

  • Pentas
  • New Guinea Impatiens
  • Elephant Ear
  • Canna
  • Fiber Optic Grass
  • Sweet Flag

There are also biological controls available. The most prevalent is one containing the fungus coniothyrium minitans. It is a natural control but not registered in some states for use.


So do I use it or lose it?

A few weeks ago, I opened the door on my garden shed and found something looking like snow drifts on the surface of my potting soil! Truly, it was white mold on my potting soil!

I store my potting soil in an old soak sink that my son discarded. And I sometimes keep an old vinyl tablecloth over the top of the soil. I do this because I forget to close the door of the shed sometimes (even overnight), and I don’t want it to become the local “outhouse” for the cats or other animals who may visit in the night.

It seems that the combination of soil and warmth and a little condensation from the soil sink being covered with a vinyl sheet, I had created a perfect environment for the mold to grow. My garden shed gets really hot through the day and then cools considerably in the nights. Here comes condensation.

Furry and white mold is called mycelium

Mushrooms, along with yeasts and mold, are examples of fungi. Mold is a type of fungus and is important in soil because it helps to break down the components of the soil into the nutrients which then are available for the plant’s roots to take nutrients in to the plant.

You see, soil is teeming with life, and most of the time it is invisible to the naked eye. But the fungi in the soil is part of the web that makes up the living organism network and results in our plants thriving in this fertile soil.

You might find some white mold on the surface of a plant’s soil in a container, but that may be due to too much moisture. Soil bagged for sale may have mold in it when it is opened, but that would be due to moisture and darkness inside that bag. Exposure to light would have the mold retreating back below the surface again.

I fixed the situation by pulling off the vinyl cover and exposing the soil to the air. I left the door open to the garden shed and just thought I could keep an eye on it in case cats, birds, wasp ( those are one of the little varmints who come looking to make a nest.) In a few days, it was almost all gone and the soil looked wonderful. In fact, I felt so confident in what I had read, I planted up my terrariums here.

If there is mold in a potted plant, just break up the soil to be sure it hasn’t created any water dam. If you like, you can replace it with new soil if it bothers you. But I am comfortable with my soil and I plan to not let it develop such a humid/moist environment in the future.

If you buy soil and it has mold, according to these sources below, that shows it is alive and doing well. Just let it get some sun and air and you are gold!

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