The following question was sent in by “MeeTom”, a resident of Nova Scotia and whilst we have our own opinions we made sure to ask all our experienced grower friends when they dropped by the store during the week. The best answer we got and the one that everyone seemed to agree upon as being the most likely came from Ken who prefers to be known affectionately as… The Lizard King.
Where does powder mildew come from? And how can I stop it from happening? It keeps forming on my plants and I keep wiping it off so it must be something I am doing wrong. If anyone can give me some advice it’d be much appreciated.
MeeTom – Nova Scotia
How is Powder Mildew formed?
I used to have powder mildew problems myself. I tried spraying with baking soda and water mixture which appears to make it look like it goes away… But it does not. It comes back within a week or so. I’ve heard of people spraying their plants with milk… But again I think this is only a wash off of the leaves and it does not actually kill the powder mildew off. In my experience powder mildew sits in the plant systemically almost like a cancer would so you have to figure out what is causing the irritation; but it’s worse because it transfers from one plant to another.
How do I Control Powder Mildew?
The only thing I have found to work for myself is temperature control. Don’t let your temperatures from Day and night differ more than about 10 or 11°C. If the plants experience temperature fluctuation more than that when the lights turn out it makes the plants go into a cold sweat and because the mildew from the cold sweat sits on the surface of the leaves for a longer period of time it creates a fungus.
Since I have set my temperatures accordingly I do not experience powder mildew problems anymore. Even when I have gotten clones from somebody else that do have powder mildew it just dies off when you have your temperatures within range.
Does this affect the resin production?
Yes of course it will but if you want the extra resin and trichomes on the plant… Pay for it with nutrients! Most of the people growing put their plants in stress or shock by dropping the temperatures the last couple weeks to get more resin on their plants but it also creates powder mildew which can also lead to bud rot.
If all else fails…
If you get to the end of flower and you cannot get rid of powder mildew I was told you can try commercial grade hydrogen peroxide one cup in 5 gallons of water and rinse the buds off in the water and then dry them out to cure them but it definitely kills the smell of the plant. I imagine it would wreck it for any kind of extract also but you would not want to make any extracts out of marijuana with powder mildew anyways!
This is my own experience. Hope it helps