Help!!! PW in seemingly ideal conditions

Hi I'm in week 2 of flower. 6 small plants under 400w hps in soil in a basement. 2 Marion Berry, 4 Headband. Plants have been super healthy from the get go but I started seeing powdery mildew spots on one of them about a week ago and misdiagnosed it as spots from big bloom water. Now it's a full
blown PM problem. I'm really concerned because I'm going to start seeing flower formation any day now.

The thing that has me confused is my conditions are not ideal for PM growth at all. Day time temps are 74-78. Night temps 68-70. Humidity 30-40% during the day 35-40 at night. I have a big circulation fan running 24-7 and an oscillator on with the light. Plants are not overly crowded.

Actions being taken:
Carefully cut off affected leaves.

Spraying with Serenade

Bringing night temps up to 70-72

Runing oscillator fan 24-7

I'm also buying a better hydrometer that can be calibrated. I'm suspecting that mine has to be off since it stays roughly roughly the same day and night even though the temps drop.

The questions:

Why the hell do I have PM? Am missing something? I have good circulation, not over crowded, temps and humidity seem good. Are they to crowded? It is in a basement that I suspect had been used as a grow room by previous tenants.

Is there anything else I should do?

And what are my odds of winning this battle? Iv read that PM actually gets in the plant, not just on the surface and will keep growing back. Someone tell me they have handled PM mid grow and secceded!


Thanks for the help

Your plants look really healthy. You'll just have to stay ontop of it by spraying it on contact till harvest. At some point after your harvest you are going to have to bleach or peroxide your entire grow. pm is airborne. I had mold probs and quickly cam to the conclusion I wanted to stay as dry as possible bc getting rid of mold is a bitch. I water every 2 days, thsat creates enough humidity in my veg room (around 40 tops). And I have a dehumidifier in flower keeping it no more then 20%. No pm anymore, no botrytis.

Diabolical666 said:

Your plants look really healthy. You'll just have to stay ontop of it by spraying it on contact till harvest. At some point after your harvest you are going to have to bleach or peroxide your entire grow. pm is airborne. I had mold probs and quickly cam to the conclusion I wanted to stay as dry as possible bc getting rid of mold is a bitch. I water every 2 days, thsat creates enough humidity in my veg room (around 40 tops). And I have a dehumidifier in flower keeping it no more then 20%. No pm anymore, no botrytis.

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Does it tend to always appear on the lower growth as opposed to the tops so that when u say spot treat it with spray your just talking about the lower growth? I really hope I don't have to spray the tops more than I just did.

Yeah these are the healthiest plants I've grown. And my first run in with PM. Go figure.

Also I really thinned out the bottom growth. Hopefully that creates some more airflow and space

i'm thinking the 'basement' is playing a role. even if your rh is 30% there may be areas of the basement that are ideal for PM and the fans stir it around and they landed on the moisture rich leaves.

Google "Horsetail grass tea" (herbal tea).
Buy it in the bulk and not in tea bags.
Brew as directed and cool it down.
Fill your sprayer and spray the plant down. Tops and bottoms of leaves AND the soil surface.
Use as needed right up to harvest!
The plants LIKE it and it's organic!

I suspect your right on your RH being more changing between night and day.

At any rate. YES you can DEFEAT PM in mid grow.
Use the tea, Next day mix up some bleach/water to sanitize the grow.
Get a garden size sprayer and fill with the bleach solution.
Move plants out of the basement and spray down EVERYTHING down there!
Floors, walls, ceiling, tables, washer & drier, furnace, nutrient bottles, measuring equipment, pots, tents, fans, exhaust equipment.....etc., etc, etc,,,,,EVERYTHING !!!!!!!!!

Bring the plants back into the room/area and set your humidity level to 40% and leave it there!

This stuff works!

The spores can come in from any air flowing from any other place it can. They can be carried in by you or visitors on your clothes or shoes.
It can be carried in by insects or pets.

Spray, Sanitize and keep your eye's open.

This DOES work. I have been PM free for over 5 years (indoors).

mudballs said:

i'm thinking the 'basement' is playing a role. even if your rh is 30% there may be areas of the basement that are ideal for PM and the fans stir it around and they landed on the moisture rich leaves.

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I think your probably right. This is in a small 10x6 room within a large unfinished basement. I really bleached down the smaller room before I started but didn't clean the bigger main room. And your also probably right that other parts of the basement do have the right conditions for pm since it's cooler. I am venting air in add out of that other room.

nickwin said:

Does it tend to always appear on the lower growth as opposed to the tops so that when u say spot treat it with spray your just talking about the lower growth? I really hope I don't have to spray the tops more than I just did.

Yeah these are the healthiest plants I've grown. And my first run in with PM. Go figure.

Also I really thinned out the bottom growth. Hopefully that creates some more airflow and space

Click to expand...

Yeah, I meant like when it pops up, hit it with yo spray THinning that out at the bottom is a great idea...Hey we all experience pm at some point. What makes you a good grower is recognizing it and tackling it. GL

You are worry-ing to much, plants look healthy. One thing about cultivation is keeping it easy - try not to make it difficult for you

Did the plants come as clones or seeds that you personally started?