Simple Steps To Prevent and Cure Powdery Mildew On Your Plants

Nothing is more frustrating than having your beautiful squash plants power through the pest dangers and heat threats of summer, make it out victorious into the cusp of fall, only to be struck down by powdery mildew brought on by the change of seasons.

What Causes Powdery Mildew?

These less-than-helpful fungi that float into your garden thrive on cool, humid nights that stimulate spore production, as well as dry days that allow the spores to spread – which is why end of summer, beginning of fall are the times where you see this threat spike.

Fortunately, this disease doesn’t always mean the death of your plants if you take quick action. So let’s dive in with preventing powdery mildew before it starts and journey on into how to cure it if it has already taken a foothold in your garden.

Preventing Powdery Mildew

The easiest way to stop powdery mildew in your garden is to prevent it in the first place. You can do this by choosing to plant varieties of plants that are powdery mildew resistant or tolerant.

Here are a few powdery mildew resistant varieties to give you a jumpstart in your search:

Cucumber: ‘Diva’

Yellow Summer Squash: ‘Success’, ‘Sunray’, ‘Sunglo’

Zucchini: ‘Ambassador’, ‘Wildcat’

Pumpkin: ’18 Karat Gold’, ‘Gladiator’

What Else Helps?

It is important to choose the planting location with care. Pick a spot that has well draining soil. This will allow moisture to reach the root base rather than setting on top of the soil, increasing the surface humidity near the leaves, and adding to the mildew problem.

Choose an area with plenty of sunlight and good air flow. If a plant is too shaded and sheltered throughout the day it can cause water to condense on its leaves and increase the spread of powdery mildew.

What To Do If You Find Powdery Mildew Despite Your Best Prevention Efforts:

If you have done all of these things, there is still a chance that the fungi spores will find your plant and attempt to set up shop. If this is the case, your plant will need a little extra TLC, but you can almost certainly salvage it:

Give It A Spritz

One of the most affective organic sprays is neem oil. If you have mild to moderate infection on your plant, spray both the upper and lower surfaces of the leaves each week until you no longer detect the mildew. Once it’s under control, spray every two weeks to prevent its return.

Got Milk?

Another interesting cure, and one I implement myself in my own garden, is to use a milk cure. There are differing options on how much milk to water ratio to include when mixing your spray but this is what works for me:

Mix 60%-70% whole milk (you want the fat in there) with 30%-40% non-chlorinated water. Spray liberally on your plants in the mornings until you no longer see the mildew. It is thought that the proteins in the milk interact with the sun to create an antiseptic effect. (As a side note, the milk spray has a couple other pleasant benefits for your plants – one being to deter aphids, and another being that used as a foliar spray, it allows nutrients to be absorbed by the leaves there by contributing to the overall health of your plant.) Follow up with bi-weekly spritzes to prevent its return.

What To Do For A Heavily Infected Plant:

If the powdery mildew infection is more rampant than a mild to moderate infection it may help you to kick it up a notch and add baking soda and a bit of dish detergent to your spray.

Here is the recipe so you can be sure you’re adding the perfect amounts of each:

• Fill the bottle with 1/2 quart of milk
• Add 3 teaspoons of baking soda
• Add one drop of liquid dish detergent
• Mix contents well
• Spray the top and bottom sides of infected leaves
• Reapply solution once a week

Keep Things Tidy

Some other very important actions to take are to remove the affected leaves if they are beyond salvageable, as well as to clean up the under area of your plants. Keeping things tidy ensures that there are as little as possible infected leaves waiting to burst back into life at the next watering. Making sure that the plants are clean and properly pruned also ensures good air flow which will aid you in your battle against the spores.

If you have your own tried and true tips and tricks to prevent and cure powdery mildew on your squash, cucumbers, and melons let us know in the comments – we’d love to hear it!

Happy growing!