Maximum Yield USA 2015 November | Page 100

WHAT TO DO ABOUT POWDERY MILDEW Avoid Large Swings in Relative Humidity It’s best to maintain relative humidity between 40-60%, with 50% being a good target. If powdery mildew is born, a lower humidity stimulates the fungus to make more spores and spread. Provide Good Air Movement Provide plenty of space for your plants and use oscillating fans to produce a gentle breeze in your garden. Stagnant air allows moisture to build up on the undersides of the leaves, creating a vapor barrier. If transpiration is disrupted, calcium uptake will be disrupted as well. Adding filters on all intake vents is also a good idea. Remove Infected Leaves At the first sign of powdery mildew, carefully remove infected leaves and discard them from the growroom. Be careful not to spread the spores in the process. 98 Maximum Yield USA  |  November 2015