With what are you spraying? Most organic compounds are safe on flowering plants. I'd be suspicious with instructions that included a water wash after spraying. Spraying plants will not cause mold in & of itself. Mold will become present dependent upon a number of elements including, heat, moisture in the room, air quality, etc. Many growers spray plants with nutrients throughout the entire season, grow & flowering. I'd recommend Zero Tolerance by Ed Rosenthal. Check it out around the web & email me for more info and any questions. Good luck!