Kill Powdery Mildew Fast With This D.I.Y. Recipe

This simple homemade recipe kills powdery mildew safely, without harming your plants or introducing chemicals into your garden.

Powdery mildew is a fungal disease that often impacts cucumbers, squash, gourds, pumpkins, and watermelons. It appears as white spots or splotches on the leaves, resembling a dusting of flour. It is particularly a problem during wet periods, or on drought-stricken plants, and can kill your plants if it gets too bad.

While some fungicides are effective against powdery mildew, if you’re gardening organically you won’t want to use a chemical agent.

Luckily, there is a homemade cure that works very well against most cases of powdery mildew, and may also work for other fungal diseases in the garden, such as black spot on roses or grapes.

This recipe is safe, non-toxic, and easy to make using common household items you probably already have on hand in your kitchen.

Here’s how to make it:

Homemade Natural Garden Fungicide Recipe


4 Level teaspoons or 1 1/3 tablespoons of Baking Soda
1 teaspoon of Mild Liquid Soap (castile or all-natural dishwashing soap work well; be sure to choose one that is biodegradable with no phosphates)
1 gallon of Water


  • Mix all ingredients thoroughly and keep agitated while using.  Then spray plants.
  • Spray all leaves thoroughly, until the solution begins to run off.  Spray the top and bottom of affected leaves, and spray all of the small new leaves, even if they don’t appear to have the fungus yet.
  • Use weekly until problem is resolved.
Recipe Source: The Grow Network

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Rose S.

An avid gardener since childhood, I love sharing my passion for gardening with others! I have gardened in a number of different climates and settings, from large fenced garden plots, to tiny patio and container gardens, and I firmly believe that everyone can learn to grow at least some of their own food - no matter where you live. Growing your own food can help you take control of your own health and food supply, and there has never been a better time to get started!

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4 thoughts on “Kill Powdery Mildew Fast With This D.I.Y. Recipe
  • Rose S.

    Hi Kathy! As this is not an oil-based spray, it will wash off during rains or after the leaves are wet, so you will need to reapply. In terms of keeping mildew at bay, you may have already answered your own question… You said your sprinkler runs twice a day?? This is very bad for your plants, as anything that wets the leaves can make them more prone to diseases of many different kinds. You should avoid getting the leaves wet as much as possible (although of course, when it rains, this is unavoidable). Drip irrigation is best, but if you have to run a sprinkler, I would recommend running it no more than twice per week. You want to water deeply and less often. This alone may help prevent mildew, but other things that can help include ensuring good air flow (again, to help keep the leaves dry), which may mean pruning your plants a bit to allow air to move easily through them, and keeping them spaced an adequate distance apart. You can also apply a good covering of mulch to the soil to prevent the spread of soil-borne diseases, and reduce the need to water as frequently. I hope that helps!

  • Kathy

    Thanks for the tip! Do you know how this solution fares when wet? We have an automated sprinkler that runs 2 times a day. I’m afraid that it will wash off the spray. Any suggestions?

    Any thoughts on what I can do to the soil to prevent this from happening next year too?

  • Rose S.

    So sorry to hear that! It can be bad – especially on squash… Hope the recipe works well for you!

  • Tsholofelo

    Thank you. My plants were badly affected last month. I even was forced to remove some.

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