Powdery mildew is an air borne fungus, it spreads through the air and the spores land on the leaves of the plants. There are some crucial aspects which can help to control and prevent the development of powdery mildew. Most growers cope with PM or Botrytis, depending on their grow setup and environment.

  • Ensure a clean environment and clean air.

Starting with a clean environment is very important. Something that a lot of people forget to check before they bring plants in. Disinfect the room or grow tent with either chlorine or UV-c handheld units. Spores can develop and spread very quickly; each spore produces a couple of million new spores.

Keeping the air in the grow room clean is another crucial aspect. Nowadays it is easy to incorporate systems which clean the air in your room continuously. By making sure that the air is clean, you can prevent the spreading of diseases like powdery mildew or botrytis very easily. An example is the CleanLight Air unit, this unit uses a strong UV-c lamp which kills the spores of fungi, bacteria and viruses in the air.

Powdery mildew

  • Optimal climate control.

Another important point is the climate control. Diseases like powdery mildew only grow and spread when the conditions are right; between 22-28 degrees Celsius and with a humidity of higher than 80%.

Additionally, temperature swings are something that also increases the development of spores. Making sure that the room temperature doesn’t have too big differences in temperature will prevent that most spores start germinating.

  • Integrate CleanLight UV-c crop protection.

Instead of using chemical or biological sprays, which increase humidity and can’t be used at any given moment, the CleanLight UV-c crop protection technology is a great method to fight and prevent fungi like powdery mildew and botrytis.

UV-c crop protection provides growers a sustainable and dry method to fight diseases like powdery mildew and botrytis on their plants. The low UV-c dose is strong enough to kill the mycelium of the fungi, but it doesn’t burn the plants. A quick swipe of the plants with a CleanLight UV-c handheld prevents the active powdery mildew or botrytis from spreading. Outdoors, the sun normally does this process, this is why most of these diseases are no problems in sunny areas.

UV-c crop protection

  • Make sure the air circulation is sufficient and the canopy is open.

Last but not least, a very basic and simple method to prevent powdery mildew on cannabis plants. Ensure a good air circulation and an open canopy. Pruning the plants from an early stage on makes sure the air can flow properly through the canopy. This prevents moist areas which will eventually become hordes of powdery mildew spores.


More information:


To read more research on the control of powdery mildew on cannabis with UV-c light, please click here.

If you would like to see some larger UV-c applications operating, check out our YouTube channel here: www.youtube.com/cleanlightbv

To find more information about the CleanLight UV-c handheld units, please visit this link.

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