How To Make Homemade Powdery Mildew Spray - Backyard Boss
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How To Make Homemade Powdery Mildew Spray

Powdery mildew is a common fungal infection that can affect various plant parts. If left untreated, it can cause buds to stop developing and leaves to die. While there are many commercialized sprays available on the market, you can also make your own at home using simple ingredients.

Learn how to make your own DIY powdery mildew spray with this recipe.

What You’ll Need

  • Clean spray bottle
  • Water
  • Horticultural oil
  • Baking soda

Step-By-Step Guide On How To Make Homemade Powdery Mildew Spray

Powdery mildew tomato plant
Image credit: Taew Jari via shutterstock

If powdery mildew has been a problem in your garden in the past, you know how disheartening it can be to see your plants covered in that tell-tale white powder. This is a type of fungal disease that affects a wide range of plants, including many fruits, vegetables, and ornamentals.

While it can be difficult to control once it takes hold, there are a number of things you can do to prevent it from happening in the first place. One of the best prevention methods is to make your own powdery mildew spray and apply it to your plants regularly.

Step One- Gathering

This recipe is easy to make and only requires a few ingredients: water, baking soda, and horticultural oil.

Baking soda is a natural fungicide that will help to prevent powdery mildew from taking hold of your plants. Horticultural oil is a non-toxic, petroleum-free substitute for common pesticides. It works by smothering the spores and preventing them from germinating.

Step Two- Mixing  

To make the powdery mildew spray, simply combine 1 tablespoon of baking soda with 1 cup of water and 1 teaspoon of horticultural oil. Mix well and store in a clean spray bottle. Be sure to label the bottle so you don’t accidentally use it on your food!

Step Three- Spraying

To use, simply spray on affected plants every 7-10 days until powdery mildew is no longer a problem. Be sure to spray in the morning so the leaves have time to dry before nightfall.

Symptoms Of Powdery Mildew Disease

Powdery mildew is one of the most common plant diseases to affect a wide range of crops. The white or gray fungus can be found on the leaves, stems, and flowers of infected plants. Symptoms include:

  • White or gray powdery growth on the surface of leaves, stems, and flowers
  • Distorted or stunted growth
  • Yellowing or browning of leaves
  • Leaf drop

Preventative Measures For Powdery Mildew

Left unchecked, powdery mildew can quickly spread through a garden, causing serious damage to plants. Fortunately, there are several ways to control this issue and keep your plants healthy. Here are some tips:

  • Remove infected leaves from the plant. This will help reduce the number of spores that can spread to other plants.
  • Water early in the day so that the leaves have time to dry before nightfall. Wet leaves are more susceptible to powdery mildew.
  • Avoid overhead watering.
  • Improve air circulation around your plants by pruning back any overcrowded areas.
  • Use a powdery mildew-resistant variety of plants if available.

If you see powdery mildew on your plants, take action immediately to control it. With proper care, you can keep your garden healthy and free of this pesky disease.

Powdery Resistant Plant Varieties

When it comes to plants that can resist powdery mildew, there are a few different varieties that come to mind. Some of the most popular include:

Garden Phlox

Garden phlox is a beautiful flowering plant that produces large clusters of brightly colored flowers. This plant is very resistant to powdery mildew and can even tolerate some shade.


Bergamot, also known as bee balm, is a member of the mint family that is well known for its resistance to powdery mildew. This plant produces beautiful red, pink, or purple flowers that attract bees and other pollinators.


Fortunately, cucumbers are one of the few vegetables that are resistant to powdery mildew. Cucumbers have a natural resistance to this disease, which means that they don’t need to be treated with chemicals or other pesticides.

However, if you notice any signs of the disease on your cucumber plants, be sure to remove the affected leaves immediately. This will help prevent the spread of the disease to other parts of the plant.

These are just a few of the many powdery-resistant plant varieties that are available. With so many to choose from, you’re sure to find the perfect one for your garden!

In Summary

Have you ever dealt with powdery mildew before? If so, what methods did you use to get rid of it? Let us know if you’ve tried our DIY recipe and if you have any tips or tricks that have worked well for combating powdery mildew in the past? Let us know in the comments below!