White Powder Mildew Help Needed

Hey All - Had noticed some slight white residue on leaves day or so after watering with EJ fertilizer blend (Currently Bloom, Catalyst, Tiny bit of Grow)... I am about two weeks into flower 12/12 cycle and just want to make sure I nip the problem in the butt sooner than later (if it is WPM)... First question - could the small white circles I have seen just be residue left over from some of the fertilizer splashing on leaves and drying? If not, I am guessing I may have start to mildew problem... Just checked today and didnt notice any (just watered with straight water yesterday), so fingers are crossed that it could just be fert residue... Being proactive, I ordered some SM-90 as I read this is a good natural/organic solution to dilute 5:1 water and use as foliar...

Any issues watering this early into flowering? I read that I can use up to week before harvest... I have plants potted in 5 gallon smart pots with mix of Fox Farms Ocean Forest, Fox Farms Happy Frog, Roots Organics, Black Gold All Organic, with Perlite and Worm Castings added.. (also mixed in some mosquito bits as I saw a few fungus gnats flying)... If I am using SM-90 strictly as foliar, any concerns I should have on impact of soil?

From what I read, I should spray once prior to lights going off and let sit... spray with water when lights go back off to keep from any buildup and do every three days for three applications... Am I missing anything?

Main concern is will there be any negative side effects from using period... especially when in flowering... Should I avoid the flower shoots and just hit larger fan leaves or cover all? Appreciate the help!!!!

if you have pm you need to control the humidity. Diluted h2o2 would wash it off. It might help if you posted a pic. Never used sm90 so I cant give any advice on that. Spray the whole plant when the lights are out.

Dr.Pecker said:

if you have pm you need to control the humidity. Diluted h2o2 would wash it off. It might help if you posted a pic. Never used sm90 so I cant give any advice on that. Spray the whole plant when the lights are out.

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Sir Dr. Pecker - Thank you for your response! I have humidity on lower end of 40s%.. two fans inside as well as a fan pushing air in and one pulling out harder... the out exhaust fan is stationed at the bottom of tent, while the in exhaust is pushing air in on top of tent.. figured this would force fresh air past all plants... Again, as my name suggests, I am a Newbie!

I will post pic when I get back to home later today or tomorrow, just on the road right now and the last I had checked... I didnt see any of these white spots... Is it possible that it COULD just be residue from fertilizer watering that dried on leaves? Just a thought...

If you do have PM, you're Ok to spray them with the following which you can make yourself. Try to keep the humidity low but if it's in the 40's and you have PM you have a strain that has absolutely no resistance to it, or your RH readings during lights out are much higher (lights out your humidity rises significantly). Also note that high RH is not what causes it, it's just a trigger that seems to be around 50%+ mark for most strains that have little or no resistance to it. Try to figure out the source, if it's clones you brought in then a good cleaning, spray the current batch to manage it until they're finished, give your room a good cleaning and you should be fine. If it's in your area, like my area has certain garden bushes covered in it, then it's pretty well impossible to keep it out of your garden (short of maybe showering, stripping every time you enter your room, not very practical). If that's the case look for strains/phenos that are resistant to it, use the following spray in veg every 2 weeks or so to keep it from starting up, all you can do is try to manage it/prevent it.

Per Gallon of Water (preferably filtered water so you know there's not a lot of other crap in it):
1 tspn. of baking Soda
A few drops of Vegetable Oil (for some reason Olive Oil seems to work better/longer)
A few drops of dish soap

GroErr said:

If you do have PM, you're Ok to spray them with the following which you can make yourself. Try to keep the humidity low but if it's in the 40's and you have PM you have a strain that has absolutely no resistance to it, or your RH readings during lights out are much higher (lights out your humidity rises significantly). Also note that high RH is not what causes it, it's just a trigger that seems to be around 50%+ mark for most strains that have little or no resistance to it. Try to figure out the source, if it's clones you brought in then a good cleaning, spray the current batch to manage it until they're finished, give your room a good cleaning and you should be fine. If it's in your area, like my area has certain garden bushes covered in it, then it's pretty well impossible to keep it out of your garden (short of maybe showering, stripping every time you enter your room, not very practical). If that's the case look for strains/phenos that are resistant to it, use the following spray in veg every 2 weeks or so to keep it from starting up, all you can do is try to manage it/prevent it.

Per Gallon of Water (preferably filtered water so you know there's not a lot of other crap in it):
1 tspn. of baking Soda
A few drops of Vegetable Oil (for some reason Olive Oil seems to work better/longer)
A few drops of dish soap

Click to expand...

Thank you! Will see if I see any spots when I get back and post pics to confirm with the experts!!

Imo without pictures, just by what your saying is..it's not pm, the fertilizer spilled on a leaf and that's probably what your seeing....does it smell like mildew?

GrowNube said:

Sir Dr. Pecker - Thank you for your response! I have humidity on lower end of 40s%.. two fans inside as well as a fan pushing air in and one pulling out harder... the out exhaust fan is stationed at the bottom of tent, while the in exhaust is pushing air in on top of tent.. figured this would force fresh air past all plants... Again, as my name suggests, I am a Newbie!

I will post pic when I get back to home later today or tomorrow, just on the road right now and the last I had checked... I didnt see any of these white spots... Is it possible that it COULD just be residue from fertilizer watering that dried on leaves? Just a thought...

Click to expand...

Could be.

If you do the baking soda method, make sure you room is running proper first otherwise you'll be respraying a few weeks later. I would recommend Nuke Em if you want to organically treat your room, if you use Nuke Em follow their directions to the T. If shit gets out of control (and you're in early veg) than Eagle 20 is safe to use, it's residual is completely gone after 180 days (the only test I've seen was a 180 day test so no idea how long it actually stays in).