DIY Natural Powdery Mildew Treatment

If you live in a region that's wet or humid, you've probably seen plants with a film of what looks like white powder. This is actually a disease called powdery mildew. A small amount of powdery mildew won't really harm plants, but if the powdery mildew spreads, it will reduce the growth of the plant (and its production of fruits or vegetables). In severe cases, powdery mildew can kill a plant.

Happily, there is an easy, homemade remedy for powdery mildew: Cow's milk.

Preventing Powdery Mildew

There are several ways to help prevent powdery mildew from appearing in the first place. These include avoiding:

* overcrowding
* over-fertilizing
* overhead watering
* watering in the evenings or late afternoons

However, even if you follow these guidelines, powdery mildew may still appear on your plants.


Milk as a Treatment for Powdery Mildew

Nobody knows exactly why cow's milk controls powdery mildew. The scientist who discovered this natural remedy, Wagner Bettiol of Brazil, was trying to avoid buying expensive commercial treatments for powdery mildew and - having an ample supply on milk on hand - decided to give it a try. Scientists believe milk may control powdery mildew because it contains salt - something they know powdery mildew responds negatively to. Some scientists also think cow's milk may boost a plant's immune system, making it fight off powdery mildew more effectively.

How to Make a Powdery Mildew Spray

Pour 1 oz. of cow’s milk and 9 oz. of water into a clean spray bottle. Shake to mix well.

It doesn't really matter how much fat is in the milk, but fat will go rancid while sitting on the plant, which in turn could attract pests. That's why skim milk is generally recommended; however, I use whole milk and have never had a problem. Oh, and don't use shelf stable milk - or any milk that's ultra-pasteurized (UHT), which includes most organic milk. Ultra-high pasteurization destroys milk's natural properties, making it ineffective against powdery mildew.

To Use the Spay

Spray all affected areas of the plant - including the underside of leaves - every three days at the first sign of powdery mildew. Thereafter, spray once a week.

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