I have no clue what this is

So a little opening details. This is my first grow. I am 30 days into flower currently. 5 gallon pots 250w super hps in 3x3x6ft tent. The air flow outtake goes outside, passive intake on bottom. Sadly no oscillating fans, but I have 2 stagnant fans directing airflow to carbon filter in tent and not directly on top of plants to prevent wind burn or whatever. I am using FFOF soil with Fox Farm Trio for nutrients. I give them each a gallon of 6.2-6.6 pH distilled/purified water per feed every 4 days or so. I live in a humid area so I am using a large dehumidifier in the surrounding room to keep humidity below 50%.
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Onto the issue. So after this last feed I have noticed these little patches showing up on the leaves. I can't seem to find pictures that look quite like it anywhere. Or maybe I just don't know what to look for. The spots are somewhat persistent, which is what has me a little worried. A part of me thought maybe it was white powdery mildew. Although the spots have a white tint to them, they do not appear powdery in any way. Although maybe this is just the very first signs of powdery mildew?? I tried looking up other forms of mildew and honeydew and all sorts of things. And haven't found anything quite like this. The spots rub off if you rub your finger over them. But they keep appearing over the plant.
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I will add though that besides this the plants overall appear pretty healthy. A slight tinge of yellow at the tips of some leaves tells me I might have a very slight nutrient deficiency. So beyond that and these spots, they appear to be doing fine. Also I took these pictures under the hps light so the coloring may appear slightly off. They are in flower so I didn't wanna expose them to light during their dark time just to take pictures with grow light off.
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If anyone has an idea of what this could be, or if it is something I should be worried about please share.

Can you rub a spot off? If yes, was it easy to rub off and what did it smell like?

rmax said:

Can you rub a spot off? If yes, was it easy to rub off and what did it smell like?

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With fully dry gloves it rubs off with a slight amount of pressure. Even the slightest bit of moisture takes it right off and the plant appears normal underneath. It's hard to get the smell because I can't tell if i'm just taking smell from the plant itself. But it just smells like a lighter version of the plant. A part of me feels that the plant is releasing this for some reason.

Could it be residual fertilizer splash?

I'm paranoid about PM. I think you need to inspect the garden more. Do you have a 25x loupe?

rmax said:

Could it be residual fertilizer splash?

I'm paranoid about PM. I think you need to inspect the garden more. Do you have a 25x loupe?

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That was actually something I suspected too. I initially failed to shake the early seedling/veg all NPK under 1 fertilizer, so now nearing the end of the bottle the liquid is a bit thick. The reason I didn't mention this, and why I don't really think this is what it is, is that the spots are continually popping up in different places. Although maybe that is just the leaves secreting the extra dense liquid??
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And yea, I'm a bit paranoid of PM as well. But everytime I look it, it just doesnt look powdery to me. Though I'm definitely keeping a close eye on it.
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And no I do not have a loupe yet. I was going to purchase one closer to harvest, but I might just go ahead and get one. It could be useful in situations like this.

Sorry to say, to me the third pic shows PM. Then you mention spots are popping up elsewhere. That's it, PM.

rmax said:

Sorry to say, to me the third pic shows PM. Then you mention spots are popping up elsewhere. That's it, PM.

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Dang I was really hoping someone would show up saying "oh yea thats nothing to worry about" lol. I suppose you just confirmed my fears. I guess I take this as a learning experience. Going to the local garden shop today to pick up some treatment. I guess first time grow I get to learn to deal with white powdery mildew lol.

Antman603 said:

Dang I was really hoping someone would show up saying "oh yea thats nothing to worry about" lol. I suppose you just confirmed my fears. I guess I take this as a learning experience. Going to the local garden shop today to pick up some treatment. I guess first time grow I get to learn to deal with white powdery mildew lol.

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Be sure to let us know what treatments they offer you and what you select.

Third pic is PM to my eyes. Always starts in the widest part of the fan leaves. Sorry. Systemic so it's through the plant by now.
I used milk and water with great success outdoors. Stinks though.

rmax said:

Be sure to let us know what treatments they offer you and what you select.

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They had a few. One was a mixed fungicide/insecticide hybrid. One was a cheaper version of fungicide. But their highest rated one was a brand called Banish. It is an organic product purely used for any type of mildew. Lights on for my girls started 10 minutes ago and I just applied it through a mister with water. I will keep track to see if the problem subsides.

Grow lol

Did the Banish banish the powdery mildew?

MustGro said:

Third pic is PM to my eyes. Always starts in the widest part of the fan leaves. Sorry. Systemic so it's through the plant by now.
I used milk and water with great success outdoors. Stinks though.

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PM is not a systemic disease. That's a myth. Look it up.

PJ Diaz said:

PM is not a systemic disease. That's a myth. Look it up.

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Damn myths!
I did look it up. Here's two links. https://www.medicinalgenomics.com/powdery-mildew-systemic/
According to them the science isn't clear yet whether it's systemic or not BUT I will stop saying it is.

MustGro said:

Damn myths!
I did look it up. Here's two links. https://www.medicinalgenomics.com/powdery-mildew-systemic/

Is Powdery Mildew Systemic? - AiroClean420

Is powdery mildew systemic? There are arguments from both camps, but one thing is for certain: you need a plan to protect against this threat.

www.airoclean420.com

According to them the science isn't clear yet whether it's systemic or not BUT I will stop saying it is.

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Your link suggests that there are two camps of belief systems: "camp systemic" and "camp non-systemic". If you look closer at those two "camps", it's interesting to notice that "camp systemic" is made up primarily cultivators, who's "evidence" of transmission spread is purely observational only, whereas "camp non-systemic" is made up of scientific degree holders who's position is based upon science.

Good points. I'm not disagreeing as I don't know the answer for sure; just repeated what I'd read.
I do know that I went 3 generations in a beloved plant and wasn't able to beat PM by cloning. I thought systemic but maybe my grow conditions.

Did the Banish work?

So the banish seems to have worked for me. Although I noticed it had mixed reviews, so I guess it's hit or miss. I mixed it as directed with water and used it as a foliar spray. But in my panic to solve the problem as quickly as possible I used room temperature purified water, instead of the distilled/spring water I normally use. Apparently the filter was ready to be changed though, because while solving the powdery mildew, I created hard water buildup on the leaves :/. Although I guess it could have been the Banish. I used some vinegar and water and was able to remove a lot of the spots. But I am now less than 2 weeks from harvest and am afraid to use any more vinegar to get rid of the rest for fear of harming the buds. I wasn't really able to find any info on if these hard water spots are going to affect harvest. The few that are left are mostly all on the fan leaves, not the sugar leaves, so my guess/hope is no. And the problem is no longer compounding while the plants seem to be growing as expected of this stage.
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I apologize for adding in my own idiotic variables. This probably isn't the best case for or against Banish as a useable product to kill/prevent PM.

Wait for it ..... “ oscillating fans “ .... you need air exchange.

Budzbuddha said:

Wait for it ..... “ oscillating fans “ .... you need air exchange.

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Yea I definitely do. I did a decent job of lining up a couple stagnant fans to direct air from my passive intake up to my carbon filter which leads through my light to outside. But I think an oscillating fan would definitely help the overall process. I will definitely invest in one for my second grow. Would you suggest a ground level unit? Or a clip fan/standing fan? I would think ground fan would do a better job of forcing stagnant air up, but I don't have a lot of ground space in my tent. 3 plants might just be too much for my 3x3 space.