What To Do When Powdery Mildew Appears During Flowering

Powdery mildew, also known as PM, is a common fungal disease that affects various plant species, including cannabis plants. It is characterized by white patches and light gray powder, which manifest under the leaves first and spread its way up. It is hard to identify this disease as a farmer since it can stay dormant in the soil until favorable conditions such as high humidity and poor airflow occur.

If powdery mildew is left untreated, it can affect your cannabis plants, causing stunted growth and unhealthy bud flowering, damaging your harvest yield. Luckily, there are various ways you can get rid of powdery mildew on cannabis without affecting its quality. Here are several healthy tips you should try. 

Pluck the Affected Leaves

Powdery mildew spores can either spread by the wind from the neighboring farms. And if cannabis plants have had this disease in the past, the dormant spores from the weeds or soil can cause a new outbreak. Therefore, as soon as the signs of powdery mildew show on the leaves, it is essential to stop its spread by plucking the infected leaves hence stopping the spread. 

Further, always ensure you don’t drop the affected cannabis parts in the garden. You should place them in a tight plastic bag, sealed, and dispose of them away from your indoor or outdoor farm. This practice will ensure powdery spores do not cause further damage to the healthy plants. 

Ensure the Plants Have Enough Spacing

One commonly ignored factor when planting cannabis is the space between one plant and another. It allows the plant to get enough air circulation and maintain the proper temperatures. 

Some environmental factors that promote powdery mildew are high temperatures and poor air circulation. It limits air movement, giving enough time for spores to drop and manifest on your plants. Fortunately, spacing your plants can help increase air circulation by allowing wind to freely move over the cannabis plants. It will reduce the spreading rate of Powdery mildew and ensure the proper temperatures are maintained. 

Use of Fungicides

Many fungicides in the market are organic-based and leave no toxic residue behind. It would be best to look for one that contains sulfur, an ancient remedy used to treat powdery mildew in cannabis plants. The vital component works by hindering fungal spores’ germination process, stopping its spread. But, be careful when handling sulfur-based fungicides since they can irritate your skin and eyes; therefore, always wear protective gear to avoid causing harm to your body. 

Moreover, fungicides with copper are also effective when dealing with powdery mildew. It not only kills fungi but also acts as an antibacterial compound. You can use it even during spring rains since it is not washed out by water. 

To continue protecting cannabis plants from powdery mildew. Apply these fungicides every 7-14 days to treat the affected leaves, and ensure the disease does not damage the healthy ones. 

Use of Baking Soda

When getting rid of powdery mildew, there are plenty of ways to counter it, and each act differently. In this case, baking soda changes the PH of cannabis leaves’ surface, and every fungus that comes into contact with the part immediately dies. This will help kill the existing leaves and protect the healthy leaves from the fungi. 

Throughout the years, cannabis growers have proved baking soda to be an effective way to treat powdery mildew. However, it can only be effective if you mix it with water and then spray the solution evenly on all parts of a cannabis plant. Additionally, constantly water your plants well before baking soda and use it when the sun isn’t hot. Test it on a small area before using it on the entire cannabis garden and watch the sample’s response. 

Apply Oil Sprays

Another common way used to eliminate powdery mildew is the use of oils. They act as fungicides and insecticides, ensuring you have healthy flowering buds for a bountiful harvest. Some of the oils you can use are neem oil, jojoba oil, and canola oil, which get rid of fungal spores at a high rate. The good thing with oils is that they will not affect the quality or taste of the cannabis plants making the final product safe for consumption.

Use Milk Sprays

Applying milk sprays to cannabis plants is also another home remedy that you can use to eliminate powdery mildew. It acts as an antiseptic that kills fungal spores, ensuring your plant remains healthy throughout the flowering period. Always mix your milk with water and experiment with a few plants by applying it to the surface and exposing it to the sunlight since it makes it more effective. 

In fact, research shows that cow milk was sprayed at least once or twice per week on a specific plant affected by powdery mildew. The report proves that a high concentration of milk spray effectively controls and eliminates this fungal disease. 


Powdery mildew is a disease that can affect cannabis plants, especially during flowering, which lowers your yields. Also, it can affect the quality of buds by changing their taste or physical appearance. Following these tips can help you eliminate powdery mildew to ensure you have healthy cannabis buds. 

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