White Powdery Mildew

Digit dude knows his stuff about WPM.

Bleach, wipe everything in the room down with bleach. the mold spores will survive time. they can survive home composting systems as well. Vacuum shit up and then get in better air circulation and grow plants that are resistant to WPM and use Si in your grows. Si adds an defence to the plant making it harder for WPM to colonize the leaves.

I should invest in a dehumidifier, then clean the room. ( You can spray a beach solution and white it all clean after. This will kill the fungus) If your temps dont run too cold and the humidity is on point you wont get mold again

Best you can do is cut off infected bits and hope it stops spreading. If not, there's no getting rid of it. Lots of anecdotal nonsense out there about this or that foliar spray but they all are useless trash. Even the fungicides a large farm has access to but normal consumers do not are not effective.. 25-33% reduction compared toa control group is not "effective." lol.. Throw it out. Anything infected is trash. Even if you 'wash' the surface, the hyphea/mycellium netowrk remains underneath the plant surface. There's no "washing" WPM from weed no matter whet some stoner says in a youtube video. Anyone reselling that trash is a sociopath or a moron. So, when you see a spot, cut off a wide berth around it... more than you think is necessary. There is no "disinfecting" moldy plant mass. anyone who says ther is not educated enough to know what they are talking about. More often than not it is climate caused. Your temps/rh likely caused condensation after lights out. Very slight chance you got a plant that just was overly susceptible to the issue, too.. or maybe some bad luck. Clean as you would normally. Spores are tougher than most microbes. I had a problem for 1.5-2 years. recurring issue... It coincided wiht a scale up in garden size. What i ddin't know was the temps dropped too fast after lights out and what was a good RH for proper VPD quickly shot to 100% and i got condensation on my leaves every night after lights out a few weeks into flower -- The timing was consistent. It didn't happen until the plants were large enough to transipire more than my dehum could handle in addition to the temp drop after lights out. Look up a dewpoint table for reference. If you are 80-82F 55-60% RH, the dewpoint is up close to 70F. That's very easy to hit after lights out depending on your local weather / furnace settings etc.... I was fanatical about cleaning... then i virtually gave up at the same time i scaled down a bit. Barely cleaned.. just didn't give a fuck. Zero problems from that grow on. there were definitely spores arrond but they never got the opportunity to grow. Cleaning is still a very good idea and i regularly scrub things down, again, lol. BUT, if you have a consistentn problem, you are likely causing it with your climate more than cleaning habits. I say that so you feel safer about next grow cycle. Clean as best you can. Fix the climate and you likely don't see WPM again. it took 3-4 weeks of stretch after flipping to flower and 100% light power to create the heat/RH combination that was danagerous. So, it happened at roughly the same time in each of my grows, lol.. like fucking clockwork. 100% due to my ignorance of what happened the first 30-60mins after lights out once the leaves were releasing enough moisture and temps rose a bit higher due to lights at 100%. Relative humidity.. and absolute humidity... if temps drop while absolute humidity remains same, then RH rises. simple as that. RH is the thing that matters vs absolute because it's how easily accessible the moisture is in the atmosphere for microbes and fungi. It's not about how much mass of moisture is ther (absolute) but rather about how easily it can pull that moisture out of the air (relative humidity). a temp/rh% probe can help inform about climate in grow area when lights go out and you cannot interrupt the dark cycle of a flowering plant. I had fixed the problem by downscaling, but the probe is useful to make sure i keep a solid gap away from dewpoint. canopy is higher RH and lower temps due to evaporation, so 7-10F gap is what i like to maintain above current dewpoint temps. The probes should show you current dewpoint and VPD too. I've read conflicting things about overwintering of mold spores that impact marijuana. I've read it does not overwinter and i've read that it can, so ther is conflicting information on this. BAsed on my limited experience, it certainly seems to have a shelf life. FWIW, when i went from infected to clean (and clean since), it was a 1-week turnaround, but then nin take 6 months off between 2 grow cycles. I may have gotten luck with the 1-week turnaround and minimal cleaning.