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How to Cure Mildew on Cucumbers

Most mildew infestations of cucumber plants are carried in by the wind. Two natural organic solutions to a mildew problem are a milk solution and a tea made from chives. However, for some more resistant infestations, a harsher natural or chemical fungicide may be required. If you live in an area prone to mildew, you can use either the milk solution or the chive tea as a preventative measure.

Milk Treatment

Mix one part milk with one part water. An enzyme in the milk helps control cucumber mildew.

Spray the plants every three or four days when you first notice the mildew.

Spray the plants weekly as a preventative measure for mildew and several other fungal diseases.

Chive Spray

Put a cup or two of chives in a glass container.

Cover the chives with boiling water.

Strain the mixture.

Spray your cucumbers two or three times a week as a preventative measure.

Other Natural Fungicides

Apply a natural copper-based fungicide according to label instructions. Be careful, however, as fungicidal levels of copper can be toxic to some beneficial organisms, like earth worms.

Apply a fungicide containing neem oil. Again, although it is a natural fungicide, the concentrations may be toxic to some organisms, like ladybugs.

If all else fails, try using minimal quantities of chemical fungicides. Be aware, though, that these can harm beneficial organisms and are not considered organic.

Make A Fungicide For Powdery Mildew On Organic Cucumbers

Growing your food organically means you have to be selective in how you treat pests and disease. Several kinds of powdery mildew affect different plants. The mold is a sort of cotton-candy vampire, sucking nutrients from the plant, so if you leave it untreated, a severe infestation can cause your plants to wither. Even if they survive, your yield will be badly affected. Start by removing the worst-affected leaves, if possible, bagging them immediately so you don’t spread the spores. If you’ve just begun to notice mold on the cucumber leaves, or if you’ve had problems in the past and want to minimize the risk of powdery mildew, milk is an easy, all-natural deterrent to the fungus. Apply weekly or biweekly. Baking soda has a long list of household uses, and you can add “treating powdery mildew” to that list. It’s especially important in the Pacific Northwest, where humidity favors the fungus’ growth. That new growth is especially susceptible to powdery mildew.


The best way to ensure that your cucumbers don't suffer from mildew is to keep your garden area as clean as possible. Keep the leaves and growing cucumbers as dry as possible.

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