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Thread: powdery mildew?

  1. #1
    BlaZinROC's Avatar
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    powdery mildew?

    I believe i have a powdery mildew problem on three of my endless sky plants 7 weeks into flower! what should i do? should i harvest early? At first i thought since the temps were getting down into the high 30's at night that it was just the resin glands reacting to the cold and almost freezing in a way but now after a week and further examination i see that it wipes right of in some spots. I'll upload pics of what it looks like later. Please, Help!

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    PharmaCan is offline Registered+
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    Get some Serenade and spray the plants. Serenade is safe to use up until the day of harvest, but it stinks to high heavens so you wouldn't really want to. Since you are a week or two from harvest, it'll be okay to use it now. Usually one application will kill the powdery mildew.

    Not that it makes much difference now, but you should be running your lights at night, when the temps drop and you need the heat.

    PC
    Last edited by PharmaCan; Dec-11-2007 at 12:53.
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    Never argue with an idiot - they drag you down to their level then beat you with experience.

    All of this is just pretend. But if I grew marijuana, it would be in strict compliance with California Law, SB420.

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    Get a heater in there and drop the %RH. If you've got the conditions for powdery mildew, bud rot isn't far behind.
    As PC says, you need to schedule your on/off hours according to desired temps.

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    The RH is never higher than 40%, normally hangs around 35. Could it be caused from just stale air also? Also,i just got a small heater from homedepot yesterday that will kick on when the temps get to 55. Should i harvest early to prevent the spread?

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    PharmaCan is offline Registered+
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    Quote Originally Posted by BlaZinROC View Post
    The RH is never higher than 40%, normally hangs around 35. Could it be caused from just stale air also? Also,i just got a small heater from homedepot yesterday that will kick on when the temps get to 55. Should i harvest early to prevent the spread?
    Well, if you don't want to listen to how get rid of the powdery mildew, by all means, harvest them now. The bud won't be as good as if you went full term and, unless you've been flushing just for fun, the plants won't be flushed. But, it's your grow so do whatever the hell you want to do.

    PC
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    Never argue with an idiot - they drag you down to their level then beat you with experience.

    All of this is just pretend. But if I grew marijuana, it would be in strict compliance with California Law, SB420.

    Live wild - it's too late to die young.

    "Let the old men who make the wars, fight the wars."

  6. #6
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    55 is too low. Set the low-on point at 65.

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    hey PharmaCan, no need to be a smart ass. The plants only have at max 10 more days so harvesting 5 early is really no big deal. Also, they are organically grown and i've already flushed them once so there aren't really loaded up with chemicals so shortening that process is really no big deal either. Will the heat help drop the humidity because last night the low was 50 and the rh got all they way up to 70%. Also, How do i got about completely switching the lighting schedule, won't this stress the ladies flowering?

  8. #8
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    pics of powdery mildew affected endless sky
    Attached Thumbnails Attached Thumbnails powdery mildew?-000_0076.jpg   powdery mildew?-000_0079.jpg   powdery mildew?-000_0081.jpg  

    powdery mildew?-000_0083.jpg   powdery mildew?-000_0084.jpg  

  9. #9
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    First 2 pics- Endless Sky
    3rd- Bag seed with about a week left
    4th pic- Random heady seed two weeks into flower, should be a beast!

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    here the pics
    Attached Thumbnails Attached Thumbnails powdery mildew?-000_0085.jpg   powdery mildew?-000_0086.jpg   powdery mildew?-000_0088.jpg  

    powdery mildew?-000_0089.jpg  

  11. #11
    stinkyattic's Avatar
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    Quote Originally Posted by BlaZinROC View Post
    Will the heat help drop the humidity because last night the low was 50 and the rh got all they way up to 70%. Also, How do i got about completely switching the lighting schedule, won't this stress the ladies flowering?
    Exactly.
    %RH depends on two variables: Temperature and actual mass of water per volume of air.
    Warm air can hold a much higher mass of water vapor than cold air.
    The dew point, at which condensation occurs (dew), is the temperature at which the air can no longer hold the same mass of water vapor, and some will condense out of the air and fall or stick to surfaces, especially surfaces that are colder than the surrounding air. Well, the water doesn't really care where it goes, but cold surfaces (like the side of a glass of frozen beveraes) are the first place you will notice that condensation is occurring.
    Anyway, the short version is, that when you increase the heat, you increase the air's water holding capacity and decrease the condensation on your leaves.

  12. #12
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    So would it be bad for my plants to sit in 22 hours of darkness so i can switch my lightning schedule? Also, Does anyone know what the coldest hours of night are this way i can coincide with them.

  13. #13
    PharmaCan is offline Registered+
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    Quote Originally Posted by BlaZinROC View Post
    hey PharmaCan, no need to be a smart ass.
    Well, yes there is, sometimes, when people ask questions simply for the purpose of trying to get anyone to agree with their pre-conceived outcome. It's just a big waste of time for those who are trying to help you.

    BTW - I grow a Master x Bubba stain that is highly susceptible to powdery mildew. It gets PM in the middle of summer when the temp is 115 and the humidity is 30%.

    Enjoy your harvest!

    PC
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    Never argue with an idiot - they drag you down to their level then beat you with experience.

    All of this is just pretend. But if I grew marijuana, it would be in strict compliance with California Law, SB420.

    Live wild - it's too late to die young.

    "Let the old men who make the wars, fight the wars."

  14. #14
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    I have no pre-conceived outcome, I know nothing about powdery mildew and how to get rid/control it. I'm simply just looking for more information on it. Chill man, i appreciate your help though. Have you heard of using a 10% milk to 1 gallon of water solution to treat? Don't really have the extra money right now to go buy something to treat it.

  15. #15
    stinkyattic's Avatar
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    Milk, I haven't heard of. Baking soda though, I have, dissolved in water. This changes the pH of the leaf surface and makes the conditions impossible for mold to grow. But I don't know a THING about that method, try googling 'baking soda plant pest'. And use the heater first.

    Extra darkness is far better than extra light.

    The coldest time of night is from about midnight to just before dawn. I run my lights about 9pm to 9am; they come on an hour early for daylight savings time (I don't make the switch) so in the mid-winter they are on from 8pm to 8am.

    And PC, can you PLEASE stop being so argumentative?

  16. #16
    sm1l3ygl4dh4nd5 is offline Registered+
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    cure?

    did anyone ever figure out how to solve this problem? I used seranade the other day on some babies that just came out of the humidity domes about a week ago and today they're already showing signs of new PM growth. Is this some sort of mutant PM? are there other ways to completely get rid of this disease other than killing off a strain?

  17. #17
    mrbigair600 is offline Registered
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    Wow sorry to see the devastation Blazin those plants took a real beating. Luckily I caught the PM in time on my crop it was going from ugly to worse but I was able to neem oil them in time to save everything. At this point along the game for you the best bet is to cut the affected fan leaves down to keep the buds from rotting. I wouldnt recomend foliar spray your pretty far along now and if you foliar fight the PM your buds will rott from the residual moisture. You can try feeding it a neem oil solution and possible some nutrient high in silicates to help keep the plant defenses up, flush well at harvest though after usage of neem! Good luck interested to see how it turns out dont smoke it if the buds are contaminated you can get very sick from that.

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