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Rose powdery mildew is a plant disease that is fairly easy to spot, as it looks exactly like its name suggests. Powdery mildew forms a white or gray powdery film on the leaves, stems, and fruits of a plant.

How to recognize and combat powdery mildew on roses? That's what today's post is about. Read on and find out which natural home remedies you can use to combat powdery mildew on roses.

What is rose powdery mildew?

Control of powdery mildew on roses and garden plants

Powdery mildew is a fungal disease caused by the many variants of the Erysiphales fungi. The fungus thrives in a warm, moist environment and overwinters in the soil. The powdery mildew forms spores that are spread by wind, insects and water runoff, spreading the disease to other plants.

Powdery mildew on roses - what helps against it?

Remedies against powdery mildew on roses and other garden plants

How to prevent powdery mildew on roses and other garden plants?

Powdery mildew usually starts on the lower leaves of a plant and if left untreated the fungus will spread throughout the plant. If the leaves are heavily covered with the fungus, photosynthesis will be impaired and the leaves will turn yellow and fall off.

Powdery mildew thrives at temperatures of 10-18 degrees Celsius and humidity of 80-90 percent. To prevent mildew from forming, avoid low temperature and high humidity environment.

Good air circulation ensures lower humidity and inhibits the development of powdery mildew.

This is what powdery mildew looks like on plants

The powdery mildew does not tolerate high temperatures. Direct sunlight helps curb mildew growth because the strong rays of the sun kill the spores before they can spread. Plants that are in the shade for most of the day stay cooler and this encourages mildew growth.

Never use infected plant leaves or fruit as mulch or compost. Remove infected leaves and stems and dispose of properly.

Rose petals affected by powdery mildew

While water itself does not encourage mildew growth, spritzing water on the leaves can spread the spores. That's why you don't use a sprinkler system to water your garden plants.

There is a wide variety of hybrid plants that are resistant or tolerant to the growth of powdery mildew. The resistant plants will be less likely to develop powdery mildew. The tolerant plants are less affected by the negative effects of a fungal attack.

What helps with powdery mildew?

Use natural remedies against powdery mildew

8 natural home remedies against powdery mildew on roses and other garden plants:

  • Potassium Bicarbonate
  • milk
  • Neem Oil
  • Vinegar
  • Baking powder
  • garlic
  • Sulphur
  • Copper Fungicides

Potassium Bicarbonate

Potassium bicarbonate is a safe, effective fungicide that kills spores on contact

Mix 3 tablespoons of potassium bicarbonate, 3 tablespoons of vegetable oil and half a tablespoon of soap in 3.5 liters of water. Spray the mixture on the affected plants.

Treating mildew with baking soda, neem oil, horticultural oil or sulfur is very effective and environmentally safe


Numerous studies have shown that milk and/or whey can kill powdery mildew even more effectively than chemical fungicides. Scientists aren't sure why milk is so effective, but they believe milk interacts with the sun to produce free radicals that are toxic to the fungus.

Milk against powdery mildew on roses

Mix 3 parts water with 2 parts milk or whey and spray on the affected plants every two weeks. You can even use undiluted whole milk for a stronger effect.


Mix 30 g milk powder with 2 liters of water and spray the affected plants twice a week.

Neem Oil

Neem Oil is made from the seeds and fruit of the evergreen neem tree and is potent enough to kill powdery mildew in less than 24 hours. The oil works by increasing the metabolism of the plant interferes and stops spore production.

Add 3 tablespoons of neem oil to 3.5 liters of water and mix well. With this you can spray the affected plants once a week. Buds and flowers of the plant are not treated after all.

Neem oil is a natural pesticide


The acetic acid in apple cider vinegar is very effective in fighting powdery mildew. Make sure the vinegar mixture is not too strong as the acetic acid can burn the plant leaves.

Mix 4 tablespoons of vinegar (5% solution) with 3.5 liters of water. Spray the affected plants every three days.

The acetic acid is very effective

Baking powder

Baking soda has a pH of 9, which is very high! The treatment with baking soda raises the pH of the plants and creates a very alkaline, fungicidal environment.

Dissolve one tablespoon of baking soda and half a teaspoon of liquid soap in 3.5 liters of water.

Spray the mixture on the affected leaves and discard the remaining amount. Do not use in daylight.

Baking powder is a natural remedy that can be found in every household

Spray the leaves of affected plants


Garlic has a high sulfur content and is an effective antifungal agent. Garlic oil can be bought commercially if you don't want to make the solution at home.

Crush six cloves of garlic. Mix together 30ml organic oil such as neem oil and 30ml rubbing alcohol. Combine garlic and oil mixture and leave to harden for two days

Strain the garlic and keep the liquid and garlic separately.

Soak garlic in a cup of water for a day. Then strain and discard the garlic.

Mix together the oil mixture and garlic water and add another 3.5 liters of water.

Spray the leaves of affected plants.

Homemade mix with garlic


Sulphur is a natural product that is very effective in preventing and treating powdery mildew. This is sold as a powder or as a liquid.

Follow dosing instructions carefully and wear gloves, eye protection and a face mask. Avoid inhaling the sulfur or with it to get in touch.

Copper Fungicides

Copper is a very effective fungicide, but it is very important to follow the instructions carefully. Too much copper is harmful to the plant and the soil.

Armed with these home remedies, you can fight powdery mildew on plants in no time!

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