Well, that's a new one. Please fill out the troubleshooting form and give as many detail as you can. I can't determine if it's a nute problem or disease like mold. Need more info, like what is your room like, if indoors. What and how are you feeding/watering and how often, etc.?
polishpollack Reviewed by polishpollack on . Black leaves I have a very healthy WW plant 4 wks into flowering. Some black marks are showing up on a couple leaves in no particular pattern. (Lights are close (13"-15"), cooled and not emitting any heat on plant. pH is 5.8 so I need to raise it. Humidity never gets above 35-55% or so.) I read that black marks may be a fungus. (Leaves in right photo are at top of plant and are closer to the HPS. Left photo are in middle of plant.) Ideas? Rating: 5