10 Homemade Powdery Mildew Sprays for Plants

Powdery mildew can spread quickly in a garden. Once it takes hold, it can weaken the plants and slow their growth [1].

Thankfully, several homemade sprays can help fight this common plant disease.

Not only are these sprays affordable to make, but they’re also better for the environment than many store-bought fungicides.

Identification

Powdery mildew is a fungal disease that appears as white to gray powdery spots or blotches on plants [2]. Left unchecked, this plant disease can drastically reduce your crop’s quality and yield.

Moreover, powdery mildew can affect a wide range of plants. Vegetables like cucumbers, squash, tomatoes, zucchini, and beans are commonly affected.

It may also affect fruit-bearing plants like apples, grapes, pears, strawberries, and pepper plants.

Even ornamental plants, including roses, zinnias, bee balm, peonies, and succulents, can be attacked by this fungal disease.

The Best Homemade Sprays for Powdery Mildew

All of these DIY sprays are practical options for controlling powdery mildew. However, remember that they work best when used at the first sign of infection.

1. Baking Soda Spray

One of the most popular home remedies for powdery mildew is baking soda spray. It can limit the spread of this plant disease.

It is often used as a natural fungicide to tackle mold and mildew on plants.

To make a baking soda spray, combine one tablespoon of baking soda with a gallon of water. Next, add a teaspoon of liquid soap and pour the solution into a spray bottle.

Finally, spray your plants, focusing on all infected areas.

2. Milk Spray

Milk spray might sound unusual, but it’s a proven remedy for powdery mildew [3].

To make milk spray for powdery mildew, mix one-part full cream milk with ten parts water.

Next, shake it up and spray it onto the affected plants, coating both sides of the leaves. Reapply this treatment every 10 to 14 days.

Milk sprays are especially beneficial because they’re gentle on plants when appropriately diluted.

3. Soapy Water

Soapy water is another simple yet effective remedy for powdery mildew. Soap helps dry out the mildew on contact.

Therefore, use mild liquid or castile soap, mixing two tablespoons with a gallon of water.

Spray the soapy water onto your plants every 7 to 14 days to help keep powdery mildew at bay. This method works well as a preventive treatment rather than a cure for mildew on plants.

4. Apple Cider Vinegar

Apple cider vinegar contains acetic acid that can burn the mildew.

Mix two to three tablespoons of apple cider vinegar with a gallon of water and spray it onto the affected leaves.

While this spray can help stop white powdery mildew, it’s best to use it sparingly, as too much vinegar can burn your plants.

Also, apply the solution once or twice weekly until the mildew clears up.

5. Neem Oil

Neem oil acts as both a fungicide and an insecticide, making it a versatile solution for your garden. It is widely used as an organic pest and disease control agent in organic agriculture.

Therefore, mix three tablespoons of neem oil with a gallon of water and two teaspoons of liquid soap. Spray the neem oil solution onto your plants, covering all the leaves.

This oil works well as both a treatment and a preventative measure. So, you can keep using it even after the mildew disappears to keep it from returning.

Moreover, you can use it in plants indoors and outdoors.

6. Potassium Bicarbonate

This remedy is more effective at treating powdery mildew than many of the other remedies on this list.

It kills the spores almost instantly. However, it works best if applied to your plants early on.

Mix one tablespoon of potassium bicarbonate with a gallon of water and half a teaspoon of liquid soap to create the spray.

7. Sulfur Spray

Sulfur has been used as a natural fungicide for centuries and remains effective against powdery mildew [4].

Mix sulfur powder with water according to the label instructions to make a sulfur fungicide spray.

Spray on a dry, cool day. However, avoid using it when temperatures exceed 80°F, as sulfur can damage plants in high heat.

8. Compost Tea

Compost tea is rich in beneficial microbes that can help fight powdery mildew.

To make compost tea, steep 2 cups of well-aged compost in a gallon of water for a week. Strain and dilute the tea with equal parts of water, then spray it onto the plant leaves.

You can also use it as it is to help control powdery mildew in the soil.

9. Garlic Spray

Garlic contains sulfur compounds that also make it an effective natural fungicide.

Follow our recipe for making basic garlic spray for your plants. Spray it onto affected plants.

Garlic spray is also gentle enough to use regularly.

10. Hydrogen Peroxide

Hydrogen peroxide also treats powdery mildew on houseplants and outdoor plants.

Mix one tablespoon of 3% hydrogen peroxide with a gallon of water. Next, spray it on plant leaves.

Arber Bio Fungicide

Arber Bio Fungicide is a commercial yet organic option for gardeners looking for a ready-made solution for powdery mildew.

This product also helps to fight off white mold, onion-downy mildew, and pin rot.

Mix it as per the instructions on the package and spray it onto your plants.

Takeaway

You can use these homemade sprays to treat or kill powdery mildew.

These natural remedies may work best on specific plants or under certain conditions. Try them all out and see what works best for you.