Powdery Mildew Cannabis: Prevention and Treatment

Not only insects, crawling living things, and rodents got an eye on marijuana plants. A greatly small-sized enemy, called powdery mildew, this is a type of fungus that could develop on cannabis plants due to humidity problems, poorly flowing air, and no enough ventilation installed within the growing area. 

This undesirable enemy of marijuana plants can cause tremendous damage to the structure and processes of it and lead to more serious damage if left untreated. Hence, in this article, we will dig deeper into understanding powdery mildew cannabis and what are the most effective prevention and treatment for this particular fungal issue. 

Powdery Mildew Cannabis

Fungal disease on cannabis plants is called Powdery Mildew and it could spread to the plants regardless of the growing area it is setup. As the name suggested, you will expect to see white powdery covering on the plants when it is infected. If left untreated, the powdery mildew cannabis will slowly affect its process of photosynthesis and lead to a lesser amount of production. The worst thing to happen is the cannabis plants will eventually reach its death sentence when exposed to such disease and no immediate solution is applied. 

Powdery mildew cannabis can happen when there is not enough ventilation and proper airflow around the growing area of your cannabis plants. This powdery mildew loves to stay in an area where there is too much humidity. The plant will build pockets that finally provide the powdery mildew a place to dwell. A similar thing could happen as well when plants are close to one another, encouraging poor airflow around the plants. 

Signs And Symptoms of Powdery Mildew Cannabis

When the plants are infected with powdery mildew, you will see signs like an apparent appearance of mycelium patches on the leaves. The growth of the plants is distorted and you notice that it becomes impeded, and when new leaves are sprouting, they will seem to be infected. Even the old leaves will be affected and you will notice a drastic change in color and patches of white will show up. Eventually, the leaves will become droopy and dry up. 


Cleaning Up

To treat powdery mildew cannabis, you need to start cleaning up the affected surface of the plant by the use of properly balanced water. The water must have an ideal pH level of around 8.0 to 8.2 to help in providing an inhabitable surface area and up to the spores, to prevent from reestablishing a future colony. 

When using sponge or towels, make sure they are clean and soaked in cold water. Once done wiping the plants with the sponge, dispose of the material correctly because the fungal spores usually attach to any things and may help in spreading the powdery mildew all over the growing area. 

Prune It 

To get rid of powdery mildew cannabis, you may try pruning. If you see any apparent yellowish leaves, you can cut or prune it to help the cannabis redirect its energy into replacing the damaged ones, given that these leaves can no longer be recovered and die off eventually. Similar to the previous treatment, keep away securely the pruned leaves to keep off the fungal spores from spreading all over the crops. 

Avoid Transplanting 

The spread of fungal spores is most likely possible when transplanting cannabis plants and help them from converting all the crops into powdery mildew cannabis. Rather, use organic compost and cover on top of the soil of powdery mildew cannabis plants affected. By doing this, it will prevent the splashing of fungal spores that it could infect the whole crops when watering them. 


Take care of your plants very well to treat powdery mildew cannabis by providing some antifungal agents, like green cleaner or essential oils which is recommended a great option due to its simplicity when utilized. Also, the majority of fungicides are easily used by just mixing it with the proper ratio of fungicides to water. 

Moreover, using milk spray will help in the treatment of powdery mildew cannabis. Just mix a ratio of 40 parts milk with 60 parts of water together as it contains enough protein contents that when exposed to sunlight, will become an antiseptic. For around ten days, use it to spray all over affected plants. 


Proper Spacing 

To prevent powdery mildew cannabis from happening, make sure that when cultivating, you provide enough space in between the cannabis plants. In this way, you are preventing each plant to get in contact with each other and minimize the transmission of infection from one plant to another. 

Managing Humidity Level

When a growing area is rich in moisture content, you may use a dehumidifier, and when outdoor growing, you can expose the cannabis plants to the sunlight. Also, when using a greenhouse or indoor growing, proper ventilation is required to help manage the humidity level within the optimal level to prevent powdery mildew cannabis. Always ensure that the whole area, no matter what is the setting, there must be free-flowing air around and the ventilation is properly installed. 

To manage the humidity level within the growing area and prevent powdery mildew cannabis from happening, use a hygrometer, and ensure that the following levels are maintained throughout each stage of growth and development of the cannabis. For the seedling stage, the humidity level must be around 65% to 80% only, for the vegetation stage, the level of humidity must be 60% to 70% only, for the flowering stage, it must be 40% to 55% level, and for the last two weeks before harvesting, the humidity level must be 35% to 45% only. 

Always remember that humidity is not the only thing that must be managed when trying to prevent powdery mildew cannabis from happening. All these, including ventilation, and airflow, if not within appropriately provided, will cause fungal spores and eventually spread throughout your crops. 

Watering Schedule 

In terms of watering your plants, make sure that you do it in a time when they will get an exposure to light source approximately more than five hours after being watered. It could either be a natural light source or an artificial one, regardless of the growing area, it must be receiving light when watered. Also, using UVC light, as recommended by some growers can help the cannabis plants, especially indoors from acquiring powdery mildew cannabis as it is effective in keeping them away from your plants. 

Pruning Time

Pruning the cannabis plants can also prevent the powdery mildew cannabis from transpiring. In this way, the fan of leaves that are not getting exposure to the light source will be eliminated to avoid getting shading instead. However, this technique is only used among growers with intermediate experience in cannabis cultivation and pruning. 

Final Words

Dealing with powdery mildew cannabis issue is easy and manageable. Despite being a devastating enemy to your marijuana plants, powdery mildew cannabis is not impossible to treat. The whole case of this fungus issue is easy to manage just by following the prevention and treatment steps above.

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