SM-90? School me!

Hey All - have heard multiple treatment for white powdery mildew, and will try if they don't work... But already ordered SM-90 and looking to use as sticking with organic and like I said, it's paid for... 10 days into flowering 12/12 cycle... Any issue is using as foliar spray over entire plant at this point in flower? Have read you can use up to week before harvest... I'm not even 100% it's WPM and will post pictures soon but want to be proactive here... Also, if I have beneficial nematodes in soil, and only using SM-90 as foliar spray.. Would it harm them at all?

After I use - 5:1 with water when lights are about to go off, and follow the every 3rd day for 3 application instructions, any other hints? Heard some talk of spraying down leaves with water after to wash off anything it killed... How long do you keep the SM-90 on prior to doing this? All help and advise is appreciated! First time grow so take it easy on me.. Haha

SM-90 is a wetting agent.The manufacturer makes no claims regarding PM.If you aren't sure it's even PM I would advise confirming that before you attempt to treat.

hotrodharley said:

SM-90 is a wetting agent.The manufacturer makes no claims regarding PM.If you aren't sure it's even PM I would advise confirming that before you attempt to treat.

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Makes sense! I've read multiple places that it does treat this but checked last night and no white spots. I think I'm just being paranoid... I'm guessing it was just some dry residue on leaves from fertilizer... Thanks for the note

I've been using it to treat PM, with good results. I don't spray at night, leaving the plant wet with lights off seems like inviting disaster to me. I have an adjustable ballast so I drop it to 50% power to avoid burn and spray early in the day, with fans a little higher speed to simulate a cloudy/windy day. Usually the next day I'll spray again with slightly higher ph water (7.5ish) to rinse, I guess because I read somewhere PM doesn't like to grow in over 7.0 environments...

SM-90 works very well for PM. It quickly knocked out PM I had on stalks, and I had no spreading to leaves. I used it once a week though veg, alternating an sm-90 spray, silica spray, and water spray. Effective with a 7:1 ratio. I've used it a few times in flower, though I'd not use it last couple weeks.. it smells nice but tastes like oily soap, yeah I tasted it.

Manf lists as wetting agent to get by Cali laws I think, it's pest control and fungi control. think neem oil. I really like it and will continue using it. I had explosive growth, not sure if it's root benefits helped but yeah. No pests other than grasshoppers which don't give a crap what you use. Be sure to PH your spray, it raises PH bigtime

Good luck

GuyLeDuche said:

I've been using it to treat PM, with good results. I don't spray at night, leaving the plant wet with lights off seems like inviting disaster to me. I have an adjustable ballast so I drop it to 50% power to avoid burn and spray early in the day, with fans a little higher speed to simulate a cloudy/windy day. Usually the next day I'll spray again with slightly higher ph water (7.5ish) to rinse, I guess because I read somewhere PM doesn't like to grow in over 7.0 environments...

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Why would spraying a fungicide at night be a problem?

Well my concern would be with leaving the grow op cool and humid, when you have PM I think that would only encourage mold/mildew growth...

GuyLeDuche said:

Well my concern would be with leaving the grow op cool and humid, when you have PM I think that would only encourage mold/mildew growth...

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Uh, were talking about spraying a fungicide...think about it.

Uh, we're trying to eliminate mold/mildew, not encourage it, and SM-90 isn't really a fungicide, it's coriander oil lol

GuyLeDuche said:

Uh, we're trying to eliminate mold/mildew, not encourage it, and SM-90 isn't really a fungicide, it's coriander oil lol

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So you are spraying a product to kill PM and it is not considered a fungicide? How does it kill PM only during daylight hours? I'm very confused by what you are saying.