Finding white mold growing on your favorite houseplants can cause a great deal of concern, is the mold going to kill your plant, is it dangerous, why has it happened in the first place and how can you stop it from happening in the future?
The good news is that the mold you’ve found is usually easily treatable, and in this article, we will explain all your options for dealing with this unsightly issue, so keep reading.
Vinegar is an effective way to kill mold in houseplants. Mix two tablespoons of white (distilled) vinegar with a quart of water and pour into a spray bottle. Liberally spray the topsoil, leaves, and stems of the plant, the mold will be eliminated after a few applications and will not damage the plant.
What causes mold to grow on houseplant soil?
Mold only needs a few things to thrive, a source of moisture, nutrients, and the correct temperature ranges. In many cases, the conditions mentioned are provided within many people’s homes, making mold growing on plant pots a very real issue.
Having said that, there are also several additional reasons that you may find a fungus growing on your ponytail palm or snake plant.
Overwatering
One of the fundamental requirements for mold to grow is moisture, and therefore, if you overwater your plants, the moisture levels within the pot will stay high enough for mold to use as a source of hydration.
Instead, find out exactly how much water the specific plant needs and do not water more than the recommended amount. This should keep the plant alive, but the moisture levels low enough to not promote mold growth.
Drainage issues
Coupled with overwatering, drainage issues within a pot will prevent excess water from being let out of the pot, increasing the overall moisture levels within it.
Not only can drainage issues lead to you potentially drowning your plant, but it also, again, provides the moisture levels required for mold to grow.
Always ensure that the pot that your houseplant is in has adequate drainage to allow excess water out.
Contaminated soil
Contaminated soil is a little trickier to deal with, as it is difficult (if not impossible), to spot whilst purchasing the plant.
If the soil that came with the houseplant you have purchased was already contaminated with mold spores, it may be in a state of hibernation, waiting for the right conditions to thrive, this will likely be when you start to water the plant.
Lack of airflow
Mold hates to be disturbed, and gusts of wind or constant supplies of fresh air make it difficult for mold to settle on one spot and start a colony. Therefore, mold is more likely to be found growing on plant pots in the quieter areas of your home where there is the least movement.
Rotting organic matter
It’s important to keep your houseplants tidy. As leaves die and fall off the plant, make sure they are removed from the soil. If they are allowed to begin to decay, mold can form, and spread through the plant’s soil and across its surface.
What does mold on houseplant soil look like?
Most commonly, mold found on houseplants is white in appearance and can have a fluffy almost cotton candy-type texture to it. It can also sometimes appear powdery or velvety. Most commonly, the mold will appear white, but darker variations can appear in a darker grey color.
The mold will usually cover the soil, leaves, stems, and any fruits or flowers. If dealing with powdery mildew, the appearance can resemble powdered sugar, and will usually have a fine coating on the leaves of the plant.
What kind of mold grows in houseplant soil, and is it dangerous?
The most common strains of mold found growing on houseplants are Mucor, Penicillium, Aspergillus, and Trichoderma. However, there is also a type of fungus known as powdery mildew (also known as white mold), that’s caused by a species of fungi called Podosphaera xanthii.
In the vast majority of cases, white mold or powdery mildew is highly unlikely to be hazardous to humans. The exception is if you were to have an allergic reaction to the mold or its spores. In this instance, you could suffer from a number of symptoms, including breathlessness, sneezing, asthma attacks, and dizziness.
Will the mold damage your plant?
White mold is more likely to be dangerous to your plants than to humans, as once it spreads, it can cause photosynthesis to become difficult and has the potential to kill a plant if left untreated. In the shorter term, the mold can affect the leaves, making them turn yellow and eventually causing them to fall off.
In the majority of cases, white powdery mildew will not cause a great deal of harm to most houseplants, but as the potential is there for damage to be caused, it may still be best to remove the mold.
How to remove mold from a house plant
Fortunately, removing white mold, from houseplants is a simple process, and there are several options available to you to eliminate this unsightly fungus.
Option 1. Vinegar
Vinegar is acidic enough to kill white mold and powdery mildew, but when diluted correctly, should not damage your plants. To use vinegar to effectively kill powdery mildew, use the following method:
Mix 2 tablespoons of apple cider vinegar mixed with a gallon of water, then pour into a spray bottle. The vinegar will only kill the mild it comes into contact with, so spray the plant liberally. It may take several applications to kill the mold using this method.
White vinegar can sometimes be picked up in larger grocery stores, but to make life even easier, I have placed a few links below so you can pick it up really easily. The vinegar is very effective at killing mold, is very affordable, and can be used to clean bathrooms and kitchens too. Clicking on the links will take you directly to the store.
Iberia All Natural Distilled White Vinegar
(US)
Aksoy White Vinegar (UK)
Option 2. Neem oil
Neem oil can be used as an effective fungicide if used correctly. To effectively control white mold on houseplants using neem oil, use the following method:
Mix 2 tablespoons of mild dish soap (not detergent), with four teaspoons of neem oil to one gallon of water. Pour the solution into a spray bottle and liberally spray the plant, including the undersides of the leaves, the soil, and any other affected area.
You may need to repeat this process for several weeks before the mold is eliminated.
Option 3. Potassium bicarbonate
Potassium carbonate (salt of tartar), is an alkaline mineral that can effectively kill white mold on house plants.
Use the following method to use potassium bicarbonate to kill mold on houseplants:
Mix 1 tablespoon of potassium bicarbonate with a gallon of water. Then add half a teaspoon of liquid soap (such as Castile soap), and pour into a spray bottle. Liberally spray the plant, including the leaves, stems, and soil. It may take several applications to notice a reduction of mold on the soil.
Option 4. Milk
You may be surprised to hear that milk can effectively kill white mold on houseplants. The science behind its efficacy is not fully understood, but it is thought that naturally occurring proteins within the milk can create a mild form of antiseptic, strong enough to kill the mold, but mild enough to prevent damage to the plant itself.
To use milk to kill white mold on houseplants, use the following method:
Make a solution of 40% milk to 60% water and pour it into a spray bottle. Once again, liberally spray the solution all over the plant, including the leaves, stems, and soil. Repeat this process once every ten days, and, if possible, spray during periods of bright sunlight.
Option 5. Pruning
In some cases where white mold has begun to damage the leaves or stems of the plant, pruning may be the last effective option.
Remove any affected leaves, stems, fruits, or flowers, and throw them away. The healthy parts of the plant should continue to grow once the mold has been removed.
How to prevent mold growing on houseplants
Prevention is always the best cure, and stopping white mold from growing in your houseplants in the first place is certainly easier than having to deal with it once it begins to establish itself.
To prevent white mold from growing in your houseplants, use the following methods:
Water appropriately
As explained earlier in the article, overwatering plants is a common cause of mold growth. Ensure you are giving your plant enough water to survive happily, but not so much that it becomes waterlogged or overly saturated.
Keep plants ventilated
Where possible, keep your plants in well-ventilated areas, such as near windowsills to give them an adequate fresh air supply. Mold spores will find it harder to settle and grow a colony where there is constant airflow.
Use preventative treatments
Some of the methods listed above to treat mold growth can be used preventatively, such as the milk method.
There are also anti-fungal sprays that can be purchased and applied as a preventative measure, but be sure to read which plants the sprays are suitable for before applying.
Q&A
Is mold ok in soil?
Mold in soil is in most circumstances completely harmless and does not need to be treated. However, there are certain strains that have the potential to cause damage to plants and can cause allergic reactions in humans, so, as a preventative measure, it may be best to remove mold when it is spotted.
Will moldy soil go away?
As a general rule, mold will not go away on its own if the circumstances remain favorable. As long as there is a source of moisture, and nutrients and the temperature range remains consistent, mold will continue to thrive.
How do I get rid of mold in soil naturally?
Apple cider vinegar and natural antifungals such as cinnamon and baking soda can be used to effectively remove mold from soil.
Can plants with mold be saved?
Plants affected by white mold can indeed be saved if caught early enough by repotting. Remove the plant from the soil, clean the pot with vinegar or detergent, and repot it with uncontaminated soil. The plant should respond well to its new environment.
Conclusion
White mold on houseplants is a common occurrence. In most cases mold is harmless to humans, however, there are certain strains that can cause damage to plants if left, so it is best treated as soon as it is noticed to prevent the plant from being potentially killed by the fungus.
