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Mold? Fungus? What do I do?

Discussion in 'Marijuana Plant Problems' started by solarguy, May 29, 2011.


    solarguy Active Member

    info on the grow:

    i am growing in a 5x5 tent and a 4x4 tent with LEDs...most of the plants are starting to get these spots on them...check out the grow in my signature to see more on the grow.

    humidity is 40-50% and temps are about 72-80...i have no AC and two days i was gone and forgot to turn on the fan and it got 86-88degrees...

    i run my exhaust and fans 24/7...

    i can wipe the white powdery stuff off the leaves but don't think this is the solution PLEASE HELP!

    View attachment 1623964 View attachment 1623965

    maps84 Well-Known Member

    You have powdery mildew and it's not good it must've gotten to humid when you went away... well It's symptoms usually appear after only 3-7 days and it will spread in a short time. Dense plant growth and low light intensity are favorable for it to do real damage. High RH is favorable for infection and conidial survival, but infection can take place at RH levels as low as 50%. Dry conditions are favorable for colonization, sporulation, and dispersal.

    As solution goes you could move it to the sun or get more lights, also try to give them space. Air flow and ventilation will discourage mildew growth. Also Powdery mildew thrives where high rates of nitrogen have been used and you do have dark leaves so try to ease it on that.

    You MUST Prune infected plants to get rid of infected parts and increase airflow. If the infestations are severe, KILL the plants that are infected. remember to disinfect your pruning tool in a bleach solution of one part household bleach to four parts water after each cut. Watering plants in the morning gives the plants the rest of the day to dry off, discouraging establishment of diseases, including powdery mildew.

    Sulfur is highly effective against powdery mildew if used in a protectant program with a minimum of 7 to 14 days between applications. Garlic naturally contains high levels of sulfur and a few cloves crushed in water can be used to make a homemade spray. Apply a sulfur-based fungicide at first evidence of mildew and repeat applications as necessary. Proper timing of fungicide applications is critical to successful control so make sure to begin at the first sign of the disease.

    Another option is to spray once a week with a solution of baking soda. Baking soda increases the surface pH of the leaf making it unsuitable for the growth of powdery mildew spores. Be sure to spray the undersides of leaves as well as the upper surfaces when using any of these sprays.

    Here's a recipe to make your own spray:
    1 teaspoon baking soda
    1 quart water
    A few drops of liquid soap
    Before treating your plants, test the spray on a few leaves to make sure they are not too sensitive.

    Credit to Outdoors at GC
    Stoney McFried likes this.

    solarguy Active Member

    thanks man, i was told that 40-50% humidity is way to high....is this true?

    should i remove all of the leaves with it on them or wipe it off?

    maps84 Well-Known Member

    40-50% is perfect. and both wipe and remove. Good luck mate!

    solarguy Active Member

    what if i wipe the leaves with a wet cloth? from what i have heard water kills mold right?
    Stoney McFried

    Stoney McFried Well-Known Member

    MAsp gave excellent advice. Water itself will not kill mold, it has to have something fungicidal, like tee tree oil, bleach, etc added to it. I've heard that a diluted solution of peroxide will help as well, sprayed on affected areas.

    maps84 Well-Known Member

    It's critical you get the infection out of your garden and you must change the environment so that conditions don't match the mildew's needs, this could mean raising the temperature or lowering humidity. it's also harmful for health to smoke infected leaves!!! molds have toxins called mycotoxins that some people may be allergic to. Symptoms of a mold allergy may include headaches, asthma and coughing. Irritation of the eyes and throat may also occur as a result of breathing mold toxins.
    It cannot be scrubbed off but you can control it using minerals, organisms or mildicides.
    solarguy likes this.

    solarguy Active Member

    thanks man, have you ever used any of the sprays they sell at the store?

    have you yourself used your baking soda method? i am in flower right now so i do not want anything to happen to the buds or have bad tasting buds...but anything is better than mold buds haha

    maps84 Well-Known Member

    If you want your bud to taste good do a good N and Mg leach prior harvest... people call it flush xD but you don't need to starve the plant all together just cut back this two elements. I had powdery mildew once and used h2o2 to treat. I just scrubbed it off every time it appeared, you could see the nasty holes from the damage it was making on the stems. I was new at this then and the infection wasn't so serious as yours so the plants fully recovered and eradicated it. I did trim every leaf with advanced symptoms and made sure every plant was getting light and air. I think that's the key to keep those issues away

    Oh I also cleaned everything and moved my plants to an sterile system. then I washed my old gear with bleach and boiling water, started using hygrozyme... etc

    Halfwatt Member

    the best way to get rid of mold on plants is to use a 10% milk 90% water mix. you can even use thiswhen in bud. spray the whole infected plant, even if you dont see it on some leaves.

    Halfwatt Member

    baking soda is messy and un neccesary. just make sure to keep it at a 10 to 20 % mix rate. dont go higher than that.

    solarguy Active Member

    really? anyone back this up?

    solarguy Active Member

    what do mean?

    today is my day off work and i have time to figure this problem out....please give any advice whether there is a spray i can buy at the store or making my own!

    *any chance my old pots did this? i didnt clea them form the last grow just put new soil in and started growing....the old plants had some mold i think but not like this where it is on every leave almost...


    milk and water works
    greencure seems to work
    pmwash is good for control
    if in veg or early flower, eagle 20 will cure the plant.
    pm is like aids, it's a plant that has a disease, it spreads it to other plants. The plant can have it, but if all conditions are good, never show it. It's when you have the right conditions, pm thrives. So, most sprays are to keep it under control and it's your job to fix the conditions to keep it under control.

    solarguy Active Member

    what works best while 3-4 weeks into flower? what is pm? thanks!
    a mongo frog

    a mongo frog Well-Known Member

    the man who said eagle 20 is right. its the best shit on the market. u will never see pm again. and be carefull if u decide to use it. if your in week 3 of flower, meaning they have been in the room for a little over 2 weeks use eagle 20.

    RIXUK Active Member

    Thats been a top method for along time,even if your bud mold while curing.
    I think you shoud try this,personnely I would and I would cut badly infected leaf off,spray your buds with this mix.
    Never had to do it my self but ive seen it advised 100s of times.


    PM= powdery mildew

    NEVER OUTGUNNED Active Member

    what about a water and 33% peroxide mix?

    maps84 Well-Known Member

    I used that mix as I wrote before but infection kept coming back. I'd look into other stuff

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