Oïdium is one of the pathogenic mushrooms that are most often found in cannabis crops. It is one of the cryptogamic diseases that can cause disastrous consequences, as is also the case with a possible infection caused by the botrytis, THE mildew, THE pythium (melting of sowing), the fusarium or alternaria, if we do not put in place some prior prevention measures. It is far preferable, that this type of mold attacks your plants rather during growth than during flowering.

Oïdium is a fungal disease which is quite easy to eliminate indoors during growth, however, this can become problematic if this fungus appears during flowering. During this article in our blog, we give you some useful tips to help you clearly identify powdery mildew, how to avoid its presence, and above all what treatment to use to eradicate your presence within our favorite garden.

  1. What is powdery mildew?
  2. How to identify the appearance of powdery mildew?
  3. How to avoid the appearance of powdery mildew?
  4. Treatment from natural products to eliminate powdery mildew


Oïdium is a fungal disease which is naturally similar to vegetable rot, because it clearly belongs to the categories of molds or mushrooms which affect the cannabis plant as many plants. It’s a cryptogamic disease which attacks both the cultures of cannabis plants indoors, as outside where the natural environment makes it easier for it, especially with the arrival of fall climatic conditions.

It is a period of the year marked by a cooler air temperature, and also by plenty of water in water, with a high humidity level. What is not a good omen for the end of the flowering of our favorite varieties, it is even an ideal period for an infection by powdery mildew, because the flowers swell energetically and produce a large amount of trichomes of resin to resin This stadium.

If you observe that a plant contains heads affected by this fungus, it will be necessary to quickly remove them and not to consume them, as this could cause serious respiratory problems.



Oïdium is one of the fungal diseases, which is easy to identify thanks to White circular spots which appear gradually on the upper part of the leaves cannabis plant. In addition, residual white powder forms on these spots, like vegetable rot whose appearance is similar to that of flour. As the propagation of the fungus, the Tasks multiply quickly and colonize all the parts of the plants (leaves, stems, ramifications, flowers).

The critical stage is reached when powdery powder spreads to the heads, and especially when appears as a white coat On the latter, because this forces us to remove all the parties affected by the disease and even to remove some which are partly healthy, but which still demonstrates an obvious infection. We therefore clearly understand that this can help greatly reduce the performance of your harvest.


It is fundamental to detect the presence of powdery mildness as soon as the first symptoms of the disease appear, because otherwise this fungus could be right all of your harvest, if you don’t make the right arrangements at the right time. The more the infection progresses, the more time passes, the more it will be difficult for you to eliminate these mushrooms.

You have to be careful not to confuse it with mildew, whose symptoms are quite similar, with the difference that the mildew produces these same stains with white powder on the underside of the leaves also. These same tasks also take on a coloring which becomes more yellowish as the disease evolution.



As part of an indoor cannabis culture, we advise you to stabilize the humidity of the space between 45 and 60 % maximum. It is also necessary to ensure a good brewing like a good air renewal of the room. It must be verified that all the fans play their role well, leaving no room for any screwed air pocket.

Give great vigilance, especially during the darkness cycle, because plants sweat quite strongly, it is therefore preferable to avoid the condensation training, especially during the last weeks of bloom. During an indoor culture, it is often wrong that we must lower the functioning of all the devices at night, it is the opposite that must be done with our equipment concerning the treatment of the Air, because it is necessary to strengthen their action at these times. 



If you are used to carrying out outdoor cannabis crops, you will already have some experience in the matter. If on the contrary you are starting, then you will have to be the greatest vigilance in the spring, but also and above all to The arrival of the fall. This change of season can be more or less early or late, unfortunately, it is something that we cannot control.

This change of season announces the arrival of abundant rains in water, just like the Suddenly refreshing room temperature outdoors. These different climatic changes have direct consequences on the development of our beautiful and thick high quality cannabis flowers. This is the reason why these fungi could affect all varieties from high quality seeds to Dominance Indica, and that it is fundamental to select hybrids that are resistant to these diseases during your purchases.

It seems important to us to also emphasize that all of the structure’s preparation work, especially the defoliation To remove many sheets on cannabis plants during growth is something to give the greatest consideration to avoid many problems afterwards.


It is a double -meaning action, because it directly makes it possible to reduce humidity at the heart of the plant structure, and therefore to eliminate any risk of the appearance of this fungus by significantly improving the passage of air, But also light, which will effectively strengthen the production of compact heads generously covered with trichomes of resin. Another unwanted plague could occur at the same time, because you might see appear insects Or harmful attack your plants, which once again reduces your chances of success during the harvest.

It is important to keep in mind that infection or contamination is most simply from one plant to another, because spores From this fungus are very volatile. They can thus be attached quite frequently to the sheets of the plant, as on the stems, ramifications or the most serious, on the precious heads of our dear cannabis plants. 

The cultivation of cannabis is not a long quiet river, because it will also be necessary to clean the environment close to your culture by prevention, by picking up all dead leaves like all the plant waste located on site, in order to to avoid rotting of this type starting to generate problems on your cannabis plants rich in CBD or in THC.


It is a fairly malicious phenomenon, because the spores are microscopic and therefore difficult to perceive with the naked eye. They are also very volatile and can be fixed on any part in the cannabis plant. It also reminds us that this could attract many harmful insects, as a associated factor, so it means that one could end up with a second problem which it would not be so easy to get rid of.

There prevention Always worth better than the infection, as the other would say, because the ravages produced by these molds and these harmfuls are dramatic to carry out the cultivation of cannabis plants, which will ultimately allow us to obtain delicious scented and covered flowers covered of a beautiful resin density. We can never repeat it enough, but it is crucial to give a large place to your requirements in the choice of high quality Seeds from the start.

Another point which must be taken into account, is that it is necessary to limit the water supply during watering in recent weeks, for two reasons, the first being to maintain vigor as the health of your roots, so that they keep intact their absorption capacity, but also because it could lead to the arrival of these molds. Also remember to avoid placing your plants in the shade, when setting up the plants in the ground. Also leave a little space between your plants, in order to ensure good renewal of homogeneous air around them.

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We will never say it enough, prevention is always the best remedy for mold such as powdery mildew, above all avoiding the use of treatment, especially during the flowering phase, which could damage the final quality as the quantity of your harvest. This is why we recommend that you always preferably use a product of natural origin as a biological fungicide, in order not to affect the point mentioned above, but also and above all to obtain a final product (flowers) which is specific to consumption and which ensures the preservation of good health.

The use of a Treatment composed of water and milk Maybe a good thing during flowering, but its action is temporary, because the fungus will reappear and continue its spread at the end of About 6 to 8 days. The preparation of the latter is very simple, just Mix 90% water (room temperature) with 10% milk, and spray directly on the leaves as on the entire contaminated cannabis plant.

You can also apply by spray a Mixture of oxygenated water and water (60ml/l), which will have the same effect and a duration identical to milk treatment. The integration of a antagonistic fungus beneficial to your mixture of earth or substrate, such as Trichoderma Harzianum is also an excellent thing to do, because it makes it possible to actively protect the life of the soil and to maintain your roots intact. Purchasing an air purifier can also be a beneficial thing, as this cleanses air quality considerably.


The use of propolis is also strongly recommended because it significantly strengthens the immune system of many living beings including man. It should not be forgotten its primary function, which is to protect the hive from different environmental plagues, including pathogenic mushrooms such as powdery mildew or mildew, for example. In order to prevent these problems, please always Buy the best quality cannabis seeds and which correspond to the specifics of your climate.

You can also find natural fungicides in the trade, such as Oidioprot of the brand Prot-Eco, which consists of a mixture of nutrients and growth factors of microflora from the extract of specific microorganisms which ultimately prevent the development of the fungus. It is a non -toxic product without dangerous residues for humans.

It is also possible to use chemicals to eliminate powdery mildew, however it will be necessary to use these during the plant growth period because they leave significant chemical residues on the heads. The application of the latter is therefore to be completely proscribed during flowering, because it would make our harvest unfit for human consumption.

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