Powdery Mildew – How to Get Rid of White Spots on Plant Leaves


Powdery mildew is a common fungus that affects many plants and appears as white spots on plant leaves. Powdery mildew can also affect the stems, flowers, and even the fruits and vegetables of plants.

Before starting or expanding your indoor garden, take the time to learn more about powdery mildew. As an aspiring gardener, you should know what this condition is and how you can treat this problem. The more knowledgeable you are about it, the easier it’ll be to have a healthy indoor garden.

What Is Powdery Mildew and What Causes It?

Powdery Mildew

Powdery mildew is a common type of fungal disease that comes in many different types. It attacks different plants, namely nightshades (eggplants, tomatoes, and peppers) and legumes (beans and peas). In addition, a wide variety of indoor plants, such as begonias, roses, and dahlias, are also susceptible to powdery mildew.

Seeing light grey or white powdery spots in the leaves of your plants is a common sign of powdery mildew. It can also cover the stems and flowers of your plants. When left untreated, powdery mildew can attack other healthy plants as the wind can carry its spores.

Aside from causing discoloration, powdery mildew can also reduce the quality of the fruits and vegetables of your plants. Severe infection from it can also hamper the development of young plants and prevent them from growing.

The fungus carrying powdery mildew thrives well in dry and warm climates. However, it also loves to stay in environments with high humidity, like the cool nights during late spring. Not giving enough sunlight or proper air circulation to your plants will also make them susceptible to it.

What Are the Most Common Signs of Powdery Mildew?

Powdery Mildew - what is

You need to know the most common signs of powdery mildew to ensure the health of your indoor plants. Early identification of this problem will increase your chances of saving your plants and your entire indoor garden.

The most common sign of it is the appearance of white powdery spots on plant leaves. These spots can also come in light gray color and look like a dusting of flour. It starts on your plant’s leaves but can spread.

Other signs of powdery mildew in plants include:

  • Powdery mildew starts as powdery, circular white spots that will eventually cover the entire leaf surface of your plants. It can also grow and attack the undersides of the leaves, as well.
  • Young plants are susceptible to powdery mildew that can cause their leaves to dry out and turn yellow. When left untreated, it can also cause young plants to wilt and eventually die.
  • In some cases, the fungus carrying powdery mildew can cause the leaves to break or twist. This fungus can also disfigure the plant and remove its leaves.
  • Over time, it can cause the buds and growing tips of the plants to become disfigured. These symptoms are more visible during the growing season. 

Once you notice any of these signs on your plants, take action immediately. Don’t wait for these symptoms to go away on their own because they won’t. On the contrary, leaving this problem unattended will only cause more damage to your indoor plants.

How Can You Treat Powdery Mildew?

Treating powdery mildew doesn’t always require complex or expensive solutions. You can easily treat this problem by using household items. As long as you regularly treat your indoor garden with the right solutions, you will eventually eliminate it.

Here are some of the most common hacks to treat powdery mildew in your indoor garden:

1. Remove Infected Portions

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As mentioned, powdery mildew can eventually spread to other plants in your indoor garden. This is especially true if your plants are growing too close to each other.

To prevent it from spreading, remove the infected portion of the plants the moment you notice any symptoms. Then, use plant clippers to remove or cut back the infected portions.

For example, if you notice it on the leaves of your plants, trim the leaves and dispose of them. Never use the infected portion as compost as the spores can spread and continue to attack other plants. Don’t forget to thoroughly wash your hands and clean the plant clippers afterward to prevent the spores from spreading indoors.

2. Use a Fungicide

Powdery Mildew - fungicide

You can use fungicides to eliminate powdery mildew in your indoor garden. Choose a fungicide that contains copper, sulfur, neem oil, or potassium bicarbonate. Aside from being effective fungicides, these compounds are also safe for the environment and humans.

Reapply every seven to 14 days to maximize the effects of fungicides. Prevent the spread of the fungus to other plants by following the label instructions carefully.

3. Use Baking Soda

Powdery Mildew - baking soda

You can also use different items at home to get rid of this from your indoor garden. You’ll be surprised how these products work in keeping your indoor garden fungus-free!

One of the most common treatments for powdery mildew is baking soda mixed with liquid soap and water. This mixture is a powerful weapon against powdery mildew as it causes fungus to collapse. Baking soda also contains high levels of sodium bicarbonate that can disrupt the ion balance of the fungal cells. This will prevent them from spreading and multiplying.

Simply mix one tablespoon of baking soda with one-half teaspoon of non-detergent, liquid soap. Once these are thoroughly combined, pour one gallon of water, mix thoroughly and transfer to a spray bottle. Spray this mixture liberally on your plants until you can no longer see any white or light gray spots.

4. Use Mouthwash

Did you know that you can use your mouthwash to keep your indoor garden fungus-free? This works because your mouthwash contains strong fungal properties that can effectively eliminate different types of fungus. After all, mouthwashes kill germs — and this can include powdery mildew spores.

For this technique, mix three parts of water with one part mouthwash and pour the solution in a spray bottle. Spritz the mixture as often as possible to infected plants to prevent fungus from attacking other healthy plants.

5. Use Milk

It might come as a surprise, but you can also use milk to eliminate it. Using milk to maintain a healthy garden is becoming a norm today, especially for novices. According to research, milk can eliminate it because its protein content creates antiseptic effects when exposed to direct sunlight.

Experts advise using a 40/60 mixture of milk to water to eliminate it effectively. You can also experiment with different solution ratios to determine which one is the most effective.

Since milk needs sunlight to activate its antiseptic properties, spray your plants with this solution during the day. Moreover, use this solution before the start of humid weather in your area. Doing so will prevent it from forming on your plants and creating any damage.

How Can You Prevent Powdery Mildew?

Treating powdery mildew in your garden is one thing, but preventing them from attacking again is another. Treating your indoor garden for this over and over again is like being caught in a never-ending loop.

Once you know your plants are susceptible to fungus, it’s time to take steps to prevent the problem from recurring. Unfortunately, spraying solutions on your plants daily to keep them safe from it is not ideal.

Follow the tips below to prevent powdery mildew. These tips are usually enough to ward off the fungus that causes it.

  • Start by improving the air circulation of your indoor garden. As mentioned, fungus thrives and multiplies in humid environments, and poor air circulation will encourage them to do just that. Thin and prune all of your plants until each of them has “enough room to breathe.” This technique can prevent the spread and growth of fungus that is already present in your garden.
  • Avoid fertilizing the infected plants thinking that this can keep the outbreak under control. On the contrary, fertilizing infected plants will only increase the spread of the spores to other healthy plants.
  • Avoid getting leaves wet when watering, as this can dampen the leaves and encourage mildew growth. When watering, strive to keep your soil moist and not wet. Too much water can create a damp environment that can attract fungus.

Get Rid of Powdery Mildew Permanently

To protect your indoor garden from powdery mildew long-term, don’t stop by treating the problem. Instead, take the necessary steps to prevent this problem from occurring again.

Your indoor garden will remain fungus-free once you follow all of the tips in this article. In addition, you won’t have any problems eliminating them if you know the signs to look for and solutions to use. Knowing this information can become your key to having a healthy and appealing indoor garden!

5 FAQs About Powdery Mildew

Powdery mildew can pose problems, especially to novice gardeners. Some aspiring gardeners might even get discouraged and give up when they see signs of it.

Powdery mildew is a common problem among plants and should never stop you from indoor gardening. Of course, seeing signs of it is alarming, but this doesn’t mean that you can’t do anything about it.

Take note of the answers to some of the most common questions on powdery mildew.

For long-term solutions against powdery mildew, you need to manage your garden carefully. Improve the air circulation of your indoor garden and avoid watering leaves from above.

Yes! You can use different products in your home to treat powdery mildew. For example, you can mix one tablespoon of baking soda with one-half teaspoon of non-detergent liquid soap to one gallon of water. This mixture is effective in eliminating powdery mildew as it causes fungus to collapse.

You can also use mouthwash or milk to treat powdery mildew in your indoor garden.

There are many ways to treat powdery mildew, and the most common is the use of fungicide. If you’re going to take this direction, use a fungicide that contains copper, sulfur, neem oil, or potassium bicarbonate. These compounds are safe for humans and pets and can effectively kill any fungus.

The most common sign of powdery mildew is the appearance of white powdery spots. These spots look like flour and usually appear on the leaves of the plants. These spots can spread in the plant’s stem, flowers, fruits, and vegetables when left untreated.

Powdery mildew is a type of fungal disease that comes from many different fungal species. The fungus carrying this disease usually attacks nightshades and legumes. Different indoor plants, such as roses and dahlias, are also susceptible to powdery mildew.


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