Molds and fungus particularly like dry foliage surfaces and humid environments, greenhouses and indoor gardens are especially susceptible to powdery mildew and mold infections. In general, relative humidity (RH) levels should be kept low (40% - 55%) and constant (fluctuating environmental factors are conducive to powdery mildew infection). Providing adequate spacing between plants will help manage the humidity level in and around the leaf canopy, while also allowing treatments to reach all surfaces of the plants. Limiting extra growth in lower leaves by trimming has shown to be helpful by limiting the most vulnerable leaves lower on the plant stem. Liquid water applied directly to high-risk surfaces can also discourage the germination of the fungal spores, but it is important to be sure this does not encourage the development of other plant specific diseases which benefit from liquid water.


Practice active sanitation methods with disinfection practices to minimize contamination.


It is important to sanitize tools, equipment, structures, and even people.

  • Boot baths or sprays for walk-in greenhouse spaces are the first line of defense for preventing tracking in pests.
  • Hand washing / hand sanitizers - antimicrobial soap is suggested between handling plants, use with alcohol based hand sanitizers for best results.
  • Tool Dip Disinfectant for scissors, trimmers, or other hand held tools. Immersing tools for 2 minutes in a disinfectant can prevent cross contaminating to healthy plants. (Such as Physan 20 Fungicide Virucide, 4 tsp/1 gal water)
  • Hard Surfaces - Don't forget to spray sanitize pots & trays, walkways, re-useable equipment, evaporative coolers/water, hydroponic tanks/tubing, and replace or wash HEPA filters.
  • Area Disinfection - between plant cycles throughly sanitize a room and all surfaces with a rated hard surface disinfectant such as (ProKure V Disinfectant, BioSafe SaniDate), spray or steam clean transportation vehicles or truck beds

Best practices like the ones listed above are easy to implement in a new environment or space as well as in current and established grows for controlling Powdery Mildew. Once your growing operation is set in motion, monitor and manually inspect plants for infection on a regular schedule, focusing on mid to lower leaves, as this is where infection most often begins. Between production cycles, all surfaces should be thoroughly sanitized and cleaned as well as all debris and leftover foliage removed. 


If you want to take it a step further because you believe your area is highly susceptible to powdery mildew, alternate use of powdery mildew preventatives such as Serenade Garden Disease Control or PM Wash at a diluted rate (we recommend ¼ strength).