White Powder Mold?

Ok RIU got one for ya ! A friend has a grow going in soil and has a white powder on some leaves the bible says it is mold ,he has good vent ,low humidity and lots of air moving in the grow room he has an extractor for moisture doing all the right things but fan leaves are getting this white powder on them ,all opinions are surely welcome for the cure Happy Farming ,Cajun

its mold,something isnt right it just dosent appear out of thin air. maybe try and clean your grow room. something is wrong if you have mold.

Powdery Mildew is a bitch. Even though your conditions are optimum, it is not enough. It could have come from a clone that had it, or from someone else's grow that had it. Either way, you have to fight it now. I've had success using a mixture of 1 part skim milk to 9 parts water. Spray the infected areas and it should retreat, especially if you have low humidity and good air flow as you say. If there is barely any, I've done well by just wiping it off the leaf. The milk spray should work, though.