A Simple Kitchen Remedy for Controlling Powdery Mildew

If you’ve been seeing white spots on the leaves of your squash or melon plants, you may have powdery mildew. Here are some tips – plus a simple DIY fungicide recipe – for controlling this fungus in your garden…

If you grow squash, cucumbers, or melons, you likely have experienced powdery mildew in your garden at some point. Powdery mildew is a fungus that appears on the leaves of these plants and others, and it has a white powdery appearance, like a fine dusting of flour. If left untreated, it can spread to the rest of the plant and eventually kill it.

While the cucurbit family is especially prone to powdery mildew, it can also afflict apples, grapes, bee balm, roses, and other plants as well. The fungus is common in both hot, dry weather, and in cool, rainy seasons. Plants that are under stress from drought or insect damage are particularly susceptible, so maintaining a healthy garden and keeping plants well-watered (preferably without wetting the leaves) is key.

As with most types of fungus, powdery mildew may also be prevented by maintaining good airflow around your plants. Proper spacing, combined with selective pruning, and keeping your plants well-watered, can help to prevent powdery mildew from taking hold in your garden. You can also plant varieties that have a natural resistance to the fungus, which is a good idea if you have had problems with powdery mildew in the past.

Prevention, of course, is the best treatment, but if you end up with a case of powdery mildew in your garden, it can usually be well-controlled with a simple kitchen remedy. This homemade fungicide recipe is useful not only for controlling powdery mildew but also for related fungal diseases such as the black spot fungus that commonly affects rose bushes.

Oh, and this treatment is not just an “old wives’ tale,” as so many garden remedies are, but is actually backed by science, as detailed here.

Homemade Garden Fungicide Recipe:


  • 4 level teaspoons or 1-1/3 tablespoons of baking soda
  • 1 teaspoon of mild dish soap (e.g., Dawn or Ivory or castile—should be biodegradable with no phosphates)
  • 1 gallon of water


  1. Mix all ingredients thoroughly and keep agitated.
  2. 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.
  3. Repeat application after 2 weeks if the problem persists.
Recipe Source: TheGrowNetwork.com


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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