Is this Powdery Mildew or what?

[dieselskunk]

This is a soil grow room temp 64* humidity 58* 3rd week of 12/12 Skunk#1. I saw the white spots and they are almost like salt, grainy more so than a powder. No harm to the plants so far. I saw pics of powdery mildew but that doesn't look right and the temp and humidity are low. I've looked over pics I can find but nothing yet.

 

[greenjeans]

It sure looks like it...sorry!!!
I treated mine with a citric acid solution - I think it was better described here....https://www.420magazine.com/community/threads/intheshed-grows-inside-out-jump-in-any-time.417558/post-5647699

 

[Smokey0418]

Sure looks like it .
Threw a complete tent out a month back 30 days in.
Terrible stuff.

 

[013]

rh is borderline needs to be pulled down as you progress thru flower

either move more air and/or bring dehum online, moving air is cheaper than moving water

 

[Smokey0418]

This is a soil grow room temp 64* humidity 58* 3rd week of 12/12 Skunk#1. I saw the white spots and they are almost like salt, grainy more so than a powder. No harm to the plants so far. I saw pics of powdery mildew but that doesn't look right and the temp and humidity are low. I've looked over pics I can find but nothing yet.

At least your temp is down. I run closer to 80 and it multiplied fast.
Peroxide can help with it.
Trying to remove leaves is a never ending battle as you spread more spores around.

 

[SmokingWings]

This is a soil grow room temp 64* humidity 58* 3rd week of 12/12 Skunk#1. I saw the white spots and they are almost like salt, grainy more so than a powder. No harm to the plants so far.

I think they call it "powdery" mildew because it looks like a powder from a distance and often looks grainy as you mention when looked at close up, especially when it first starts growing.

I call powdery mildew a parasite. It is a fungus that is living on the surface of the leaf and is sucking the nutrients it needs from the cells in that leaf. Most of those areas will wipe off but often enough it comes back. If you treat the mildew properly it will die but it will not completely rub off. The area where it was on the leaf will always show up like some sort of scar.

It sure looks like it...sorry!!!
I treated mine with a citric acid solution - I think it was better described here....https://www.420magazine.com/community/threads/intheshed-grows-inside-out-jump-in-any-time.417558/post-5647699

The link that "greenjeans" provided discusses the search for a spray for mildew. The same person posted his recipe in the message linked below:
https://www.420magazine.com/community/threads/thrips.512473/page-5#post-5519939

 

[pawtz]

Not very knowledgeable on these issues, but I had this early on in my grow. I dabbed some milk on the leaf w/ a q-tip and left it on for a minute and then wiped it off w/ a different clean q-tip. I then hit the leaf w/ some water and wiped that off with a paper towel. It never came back after that. Hopefully yours is an easy fix as it was with mine.

My rh was high during that period and the mist from the humidifier was hitting a fan and blowing towards that area. I rearranged things a bit and dropped the rh down (my humidifier is on a timer w/ 30min intervals that clicks on once every 4 hours for 30min(completely off when lights off) (had to dial this in to find my sweet spot)).

 

[dieselskunk]

I sprayed acv milk mixed with water on them and put the air cleaner fan on them to move air around. Glad no buds are forming yet.

 

[SmokingWings]

I dabbed some milk on the leaf w/ a q-tip and left it on for a minute and then wiped it off w/ a different clean q-tip. I then hit the leaf w/ some water and wiped that off with a paper towel. It never came back after that.

The same thing can be done by just dabbing with a water soaked q-tip and wiping it off. That skips the milk step. One of the licensed recreational grows in this area does that sort of thing. They send a crew out with clean cloths and a bottle of water. Their job is to get the spots of mildew wet and then wipe them off. The family member who told me this was in building and HVAC maintenance and not the plants themselves so he did not pay attention to whether the company had a mildew spraying program.

The reason so many gardening web sites mention a "milk and water" is that the milk will start to sour and increases the lactic acid level so it is more efficient if it is not wiped off. The lactic acid coats the leaf and the layer of acid makes the surface less hospitable to the start of mildew growing there.

 

[kosio bosio]

The best thing that always works for me was hydrogen peroxide.
I've used it in flower or in veg. And I must say if you are consistent enough with the sprays you will get rid of that annoying PM. My buddy states that it also kills spider mites but I am not sure about that.

 

[pawtz]

The same thing can be done by just dabbing with a water soaked q-tip and wiping it off. That skips the milk step. One of the licensed recreational grows in this area does that sort of thing. They send a crew out with clean cloths and a bottle of water. Their job is to get the spots of mildew wet and then wipe them off. The family member who told me this was in building and HVAC maintenance and not the plants themselves so he did not pay attention to whether the company had a mildew spraying program.

The reason so many gardening web sites mention a "milk and water" is that the milk will start to sour and increases the lactic acid level so it is more efficient if it is not wiped off. The lactic acid coats the leaf and the layer of acid makes the surface less hospitable to the start of mildew growing there.

It for sure seemed that easy. I didn't even look into the science of why milk was even needed. Just that it was suggested. It did wipe off very easily with minimal pressure applied when using a q-tip. My last ditch effort was to just wipe it off once more(if it came back) and leave the milk on there to dry overnight or just to leave it on for good. Either way it seemed very easy on my end. So glad it never came back. Was reading all the horror stories of people saying theirs kept coming back.

 

[dieselskunk]

Well the milk/acv worked well. 2 years ago I lost 2 outdoor plants late August 2 years ago to mold, High Times Picture worthy plants. I bought *umbollts secret flower shield figuring they were in the know. The secret was it did nothing. The washing leaves idea is a good one and if it comes back I might try it

 

[cbdhemp808]

hey @dieselskunk, good to hear the milk worked on your PM. I just went through a horrible PM bout with my outdoor greenhouse plants here in Hawaii. 4 plants, now in the flower house and doing much better, thanks to a big change in the weather from rainy, super humid, warm... to clear skies, sunny hot days, and cool nights. I did a lot of defol of those girls, and they definitely suffered from that, but they are looking OK. I also sprayed them with a lot of hydrogen peroxide solution. I also ordered potassium citrate powder, to give that a try for a foliar spray next time the mold rears its ugly head.

happy growing!

 

[Jonny5]

Hey D S , I’m an outdoor organic grower, The milk spray will work and keep it in check, if you choose to use the hydrogen peroxide make sure you get the mixture rite, Hydrogen is an oxidizer and can be quite harmful if not applied correctly

 

[kosio bosio]

Hey D S , I’m an outdoor organic grower, The milk spray will work and keep it in check, if you choose to use the hydrogen peroxide make sure you get the mixture rite, Hydrogen is an oxidizer and can be quite harmful if not applied correctly

How do you mix your peroxide?
I do commercial grade 17 ml - 20 ml per gal.

 

[Jonny5]

You will have to look that one up K I’m not in the position to give that advice as I never use it.

 

[kosio bosio]

You will have to look that one up K I’m not in the position to give that advice as I never use it.

Got you. I was curious. Last time I tried 20 ml per gallon and it worked pretty well.

 

[Jonny5]

Good deal, I have done a little research on it and only mentioned it because if mixed to strong it would do more harm than good, was reading up on the black mold that appears on branches and stems and apparently it is a soil porn pathogen that enters through the roots and is present within the plant.. hydrogen peroxide used in a half n half mixture as a soil drench prior to planting is able to kill it,,, But also not so good for the living soil, still have more Research to do on this subject

 

[kosio bosio]

Good deal, I have done a little research on it and only mentioned it because if mixed to strong it would do more harm than good, was reading up on the black mold that appears on branches and stems and apparently it is a soil porn pathogen that enters through the roots and is present within the plant.. hydrogen peroxide used in a half n half mixture as a soil drench prior to planting is able to kill it,,, But also not so good for the living soil, still have more Research to do on this subject

I had a buddy who accidentally did double dose (40ml per gal).
When we turned on the lamps at first we thought - damn how come those buds got so shiny and coated in crystals overnight. Unfortunately it was the H2O2 burning the buds...

 

[cbdhemp808]

RE: peroxide foliar spray for mold control

I have been using 6 fl oz of 3% peroxide in 1/2 gal pure water. Sometimes 1 or 2 fl oz more. (6 fl oz = 12 tbsp.) Use distilled water if you don't have access to pure water.

This works out to 177 ml per 1/2 gal, or 355 ml per gallon.

I haven't had any ill effects from this concentration. I spray the whole plant, including buds. I blast buds with this stuff. Spray one day, spray the next day if needed, etc. Best time to apply would be early morning, so it can do its work, then dry out during the day.

K. Morrow** recommends 4.5 tbsp per 1 pint distilled water. This equals 2.25 fl oz per 1 pint. Which equals 9 fl oz per 1/2 gal. (I usually use 6 fl oz per 1/2 gal water.)

** Marijuana Horticulture Fundamentals, 2016