This Is How You Kill Powder Mildew Forever!!!!!

[grapeman]

I have a question.

After harvesting I plan on wiping down my tent and turning off my fans, leaving my 600w on to raise the temps to kill off the spores. I should be able to easily get temps to 90 deg +. They stay 10 deg over ambient with the fan running (70 deg room temp).

Question is how long should I keep the temps that high? An hour, 2 or 3, all night?

Krunch?

You're not going to kill spores by leaving your lights on. Powdery mildew thrives in temps up to about 105 degrees. And to kill spores by high temps, you'd need to go quit a bit higher then that and probably combine your high temps with some sulfer fuming.

Just wash down your area with physan 20 or bleach and start fresh with a proper fungicide.

Don't doubt me, I know quit a bit about this disease.

 

[Mountain]

And to kill spores by high temps, you'd need to go quit a bit higher then that and probably combine your high temps with some sulfer fuming.

Just wash down your area with physan 20 or bleach and start fresh with a proper fungicide.

Don't doubt me, I know quit a bit about this disease.

Soooo what temperature do you need to keep your room/space at to kill spores and for how long? Probably (?) combine higher temps with sulfur burning?

So washing your space down with Physan 20 or bleach will get into every nook and cranny where spores can hide? I think not. I wouldn't waste my time washing down an area in an attempt to kill spores. Housecleaning always helps though!

Out of all the products I tried for PM Eagle 20 worked the best bar none and I'm talking baking soda, milk, blah blah...but never did try CC's lavender tea treatment but yes did mess with Physan 20 among other things. Still though Krunch's treatment method probably the best for the average grower if you wanna handle something like that. Eagle 20 stinks worse than just about anything I ever ran across! I went organic after trying Eagle 20 so not an option any more.

 

[krunchbubble]

4 years PM free without Eagle 20, potassium bicarbonate, sodium bicarbonate, et al.

About $.20 per gallon for suggested application rate.

CC

your pretty lucky! i haven't had any success with it.
i used the sodium bicarb for budrot control and it fried all my hairs, and i used it a half strength....

 

[growshopfrank]

The only downside to eagle 20 is the smell, its reminiscent of a smoldering fire in a meth lab.

 

[llewop]

Soooo what temperature do you need to keep your room/space at to kill spores and for how long? Probably (?) combine higher temps with sulfur burning?

So washing your space down with Physan 20 or bleach will get into every nook and cranny where spores can hide? I think not. I wouldn't waste my time washing down an area in an attempt to kill spores. Housecleaning always helps though!

Out of all the products I tried for PM Eagle 20 worked the best bar none and I'm talking baking soda, milk, blah blah...but never did try CC's lavender tea treatment but yes did mess with Physan 20 among other things. Still though Krunch's treatment method probably the best for the average grower if you wanna handle something like that. Eagle 20 stinks worse than just about anything I ever ran across! I went organic after trying Eagle 20 so not an option any more.

Wash down your room and don't worry about the few spores left in the corners. While each spore has the ability to infect your plant, it is highly unlikely that this will occur because of the plants natural defenses. Its only when the plants defenses are overwhelmed that the positive feedback loop of virus, bacteria, and fungi production takes over.

 

[Mountain]

Wash down your room and don't worry about the few spores left in the corners. While each spore has the ability to infect your plant, it is highly unlikely that this will occur because of the plants natural defenses. Its only when the plants defenses are overwhelmed that the positive feedback loop of virus, bacteria, and fungi production takes over.

Then why bother to wash down your room at all?

 

[llewop]

Then why bother to wash down your room at all?

??? huh, you wash down your room so that there are not a bunch of live spores that could be blow onto your plants.

Consider this analogy in the human body. On a daily basis we're exposed to virus's and bacteria, but were not always sick. Our bodies immune system is able to fight off 99.9...% of the pathogens. Its only when the immune system is compromised or were exposed to extreme number of pathogens (Not washing your hands before eating) that the chances of being sick greatly increase. This analogy is very simplified, but you get the idea. Basically the plants immune system should be able to fight off a few leftover spores, while large numbers of spores have a much higher chance of infecting the plant and multiplying

 

[PuReKnOwLeDgE]

I thought this thread was to the point where people return, say how great eagle 20 worked, and that was that....

Step 1: Spray eagle 20

Step 2: Wash room down

Step 3: Get back to growing

I recieved a couple clones with PM, it was my first experience with it. I sprayed milk/water for 4-5 days while my eagle 20 was enroute. I sprayed everything in veg that was near the clones, washed the room, and it has been months now.

Order eagle 20 and forget about it already, PM is a thing of the past thanks to this thread.

 

[grapeman]

Soooo what temperature do you need to keep your room/space at to kill spores and for how long? Probably (?) combine higher temps with sulfur burning?

So washing your space down with Physan 20 or bleach will get into every nook and cranny where spores can hide? I think not. I wouldn't waste my time washing down an area in an attempt to kill spores. Housecleaning always helps though!

Out of all the products I tried for PM Eagle 20 worked the best bar none and I'm talking baking soda, milk, blah blah...but never did try CC's lavender tea treatment but yes did mess with Physan 20 among other things. Still though Krunch's treatment method probably the best for the average grower if you wanna handle something like that. Eagle 20 stinks worse than just about anything I ever ran across! I went organic after trying Eagle 20 so not an option any more.

I'm not arguing with you, just pointing out to the poster that hi temps will not kill spores without some sulfer fuming.

I haven't used Eagle myself. I use products like Flint, Elite, Bayleton, Rally or Pristine and others about a week before I move plants from the veg room to the flower room when needed. I haven't needed to apply a fungicide for over a year now. Eagle is just a product that you can get on eBay. You can't get the products I have, unless you have a Ag Permit. They all work.

As far as physan 20 goes, it's a great product to use to clean your room and supplies prior to planting. I think it smells better then bleach.

 

[Mountain]

I'm not arguing with you, just pointing out to the poster that hi temps will not kill spores without some sulfer fuming.

Honestly never looked too much into the temp thing except remember that there seemed to be a threshold where spores were deactivated. I understand the concept of keeping an area clean and my growroom was probably the cleanest place in the house. I only used Physan 20 once in a res when I was running hydro. Normally I would just sweep, mop and wipe down easily accessible surfaces. I dunno...if burning sulfur is part of the formula then why not just do that and forget about raising temps? Not trying to be a jerk.

This analogy is very simplified, but you get the idea.

I understand the idea. My experience with PM was all the cleaning in the world did not make a difference. I think it's more an immune system weakens, regardless if plant or human, then an 'infection' takes hold and not necessarily because it's being bombarded with spores/viri/bacteria (as it usually always is to some extent as there is no sterile growing enviro)...that's what I believe anyway. I've run mostly indoors and even when there was PM raging outside it never infected the strains I was running that were clean. The problem seemed always to be with bringing in infected cuts.

I thought this thread was to the point where people return, say how great eagle 20 worked, and that was that....

I did that, got infected cuts from someone, that same person gave me Eagle 20, started growing out the cuts in a brand new location with new equipment and PM showed up fairly fast (as I believe they were treated before I got them), I sprayed the plants down thoroughly, cleaned everything the best I could and...the PM came back 2 months later. I will say that Eagle 20 worked better than anything else I tried but not a cure...for me.

I never really did lick the PM thing...even with Eagle 20.

 

[Dr.Dank]

If you Have PM you must get the Eagle20! Thanks Krunch some serious shit!
I was Freaking out never seen this powdery mildew stuff till i came to California.. shits everywhere here... whos behind this mildew spread? it must be the goverment or greedy growers trying to fuck everyones Crop lol seriously thanks this stuff Killed my mildew for sure.. I do know it has strong chemicals.. but if your worried about that veg plants for longer and wash off.....i think the residue is supposed to leave in 4 months..? guy at hydro store was giving me shit about using it for smoking material..... I did spray them before putting them to Flower.

 

[kstampy]

The guy at the hydro store gave you shit because he won't be making money selling PM band-aids to you or your friends Dr.D.

 

[kstampy]

Honestly never looked too much into the temp thing except remember that there seemed to be a threshold where spores were deactivated. I understand the concept of keeping an area clean and my growroom was probably the cleanest place in the house. I only used Physan 20 once in a res when I was running hydro. Normally I would just sweep, mop and wipe down easily accessible surfaces. I dunno...if burning sulfur is part of the formula then why not just do that and forget about raising temps? Not trying to be a jerk.

I understand the idea. My experience with PM was all the cleaning in the world did not make a difference. I think it's more an immune system weakens, regardless if plant or human, then an 'infection' takes hold and not necessarily because it's being bombarded with spores/viri/bacteria (as it usually always is to some extent as there is no sterile growing enviro)...that's what I believe anyway. I've run mostly indoors and even when there was PM raging outside it never infected the strains I was running that were clean. The problem seemed always to be with bringing in infected cuts.

I did that, got infected cuts from someone, that same person gave me Eagle 20, started growing out the cuts in a brand new location with new equipment and PM showed up fairly fast (as I believe they were treated before I got them), I sprayed the plants down thoroughly, cleaned everything the best I could and...the PM came back 2 months later. I will say that Eagle 20 worked better than anything else I tried but not a cure...for me.

I never really did lick the PM thing...even with Eagle 20.

To be cured for 2 months and it to come back would be a red flag for me, something must be up in your new place inside or outside or perhaps they were not treated properly. Just a couple suggestions, I hope you fix your problem.

 

[Mountain]

To be cured for 2 months and it to come back would be a red flag for me, something must be up in your new place inside or outside or perhaps they were not treated properly. Just a couple suggestions, I hope you fix your problem.

I'm probably odd man out with it not being a cure. Stopped growing but still think about the dynamics of what transpired. I have a hypothesis or two. They for sure were treated properly, I cleaned everything up best I could, not a time of year with active PM outside, etc. I still scratch my head about it a bit.

 

[Montana]

Eagle 20 is HUGE nono!! you guys should NOT jump on this bandwagon, this shit is seriously horrible for cannabis.

This shit IS NOT the cure all for PM, use other methods PLEASE! for your sake and the plants, and for any unsuspecting poor mofo that ends up smoking your weed, you might as well be using gasoline, fuck you guys don't be so quick to trust this one, you'll see what I mean when you smoke your toxic eagle 20 weed, you just wrecked your crops......


CULTURAL CONTROL

Heat

Powdery mildew is sensitive to heat. Neither species will grow at 90 F (32 C). and will quickly perish when above 100 F (38 C).

To get a complete kill maintain the temperature for an hour. This may not be a feasible option in most indoor gardens for several reasons. The first is that it may be difficult to heat the space to such a high temperature. The second is that even a single peak of 100 F (38 C) affects the growth of plants. Vegetative plants with flowers or fruits in mid stage growth (weeks 3-7) may stretch a little from the experience. The heat treatment has relatively little effect on first and second week flowers or flowers nearing maturity.

You can minimize heats impact on plants in several ways. Heat the garden at the end of the day, as the lights are turned off. Since the plants are not photosynthesizing, they have lower water needs.

If the plants are being grown hydroponically, lower the temperature of the water to 60 degrees. Keeping the roots cool will help the upper plant parts beat the heat. It's not difficult to do this, even if you don't have a water chiller. Just add ice to the reservoir or flow through system. Roots of plants growing in soil can also be cooled using thermal ice packs at the base of the stem.
The heat treatment should kill off most of the fungus and its spores. The chances are there will still be some fungal re-growth. These can be eliminated using spot treatments.

Pruning

If one particular plant seems to be infected with a few tiny white spots on a few of its leaves, get a bag large enough to drop the leaves into and then cut them off into the bag. Remove the bag from the room. This prevents spores, the white powder on top of the leaves, from becoming airborne while being removed. Remember to wash your hands and clean the scissors or knife with soap and water, hydrogen peroxide, alcohol or bleach. Spray the plant with one of the sprays listed below after pruning to prevent re-infection and encourage healing.

If, you notice a re-infection a few days later, there is a good chance that this plant is very susceptible to powdery mildew and presents a good location for the infection to start and spread from. The plant should be removed immediately by placing a bag over it and removing it from the space. Then the space should be sprayed with one of the sprays listed below.


ORGANIC and IPM CONTROL

Here are some sprays that you can use to control the powdery mildew in your crop. All of these are safe to use for herb or for edible crops. Sprays are washed away by water, including rain.

Cinnamon Oil and Tea
Cinnamon is an effective destroyer of powdery mildew, with an effectiveness rate of 50-70%. It won't kill it completely but it will keep it in check somewhat. It also potentiates other suppressive sprays so it is good to use in combination. To make your own, boil water, turn off the heat and add one ounce of ground cinnamon to one and a half pints water. Let the tea cool to room temperature. Add half a pint of 100 proof grain alcohol or rubbing alcohol and let sit. Strain the cinnamon. The spray is ready to use. A faster method is to add 2 teaspoons cinnamon oil to one pint of water and a dash of castile soap. Other herbs are also fungicidal. Clove, rosemary, and wintergreen oils are used in some botanical fungicides. The solution should consist of no more than 2% oil.

Garlic
Garlic is antifungal and anti-bacterial and has several pathways for destroying fungi including its high sulfur content. It can also be added to other anti-fungal sprays. Several garlic sprays are available commercially.

A homemade formula: Soak three ounces of crushed garlic in one ounce of neem or sesame oil and 100 proof or higher drinking alcohol or 70% or higher rubbing alcohol for a day or two. Strain. Then soak the garlic in a cup of water for a day. Strain. Mix the oil/alcohol, soaked water and 1 tablespoon liquid castile soap in a gallon container. Then fill with water and shake. The formula is ready to use.

A simpler brew consists of a teaspoon of garlic oil in a pint of water. To keep the oil and water mixed add a 1/8teaspoon of soap. Use garlic as a vaccination. Spray on new growth before there is a sign of infection.

Garlic is a general purpose insecticide as well as fungicide, so it should be used with caution on outdoor plants. It kills beneficial insects as well as plant pests.

Hydrogen Peroxide
Hydrogen peroxide (hp) is a contact fungicide that leaves no residue. It is an oxidized product of water and has an extra oxygen atom that is slightly negatively charged. When it comes in contact with the fungi the oxygen atoms attach to molecules on the cell walls, oxidizing or burning them.
Household hp sold in drug stores has a concentration of 3%. Garden shops sell 10% hp. Zerotol contains 27% hydrogen peroxide and an unstated amount of peroxyacetic acid. Together they have a more potent chemistry than hp, with an activity of about 40% hp. It is considered hazardous because it can cause skin burn similar to that caused by concentrated acids.

To treat plants with drug store grade 3% hp use 4 1/2 tablespoons and fill to make a pint of solution, or a quart of hp to 3 quarts of water. With horticultural grade 10% hp use about 4 teaspoons per pint, 5 ounces per gallon. With Zerotol use about 1 teaspoon per pint, 2 1/2 tablespoons per gallon.

Limonene
Limonene is refined from the oil of citrus rinds. It has a pleasant citrus odor and is the active ingredient in many of the new cleaning products. It also has fungicidal qualities. I've used pure diluted limonene and it controlled powdery mildew, but did not eradicate it. Perhaps a higher concentration would have been more successful. Start using 0.5-1% limonene in water 1/2-1 teaspoon per pint.

Milk
Milk kills powdery mildew so well that both home and commercial rose growers all over the world have adopted it for their fungicidal sprays. Use one part milk to nine parts water. I've only used 1% milk, but other recipes call for either whole or skim milk and use up to 1 part in 5 milk. Some recipes add garlic or cinnamon to the mix. When using more than 30% milk, a benign mold is reported to grow on top of the leaves. Use a milk spray at the first sign of infection then protect the new growth weekly.

Messenger
Messengers active ingredient is a naturally occurring protein called harpin that stimulates the plant's own natural defense system. It has been proven to promote more vigorous hardier plants that are more resistant to disease and have increased yields. It is used to prevent infection and decrease its virulence

Neem Oil
Neem oil is pressed from the seed of the neem tree (Azadirachta indica), native to Southeast Asia, but now cultivated worldwide. Neem oil has low mammalian toxicity. It degrades rapidly once it is applied so it is safe for the environment including non-target species and beneficial insects.
Neem oil protects plants with its fungicidal properties: it disrupts the organisms metabolism on contact, forms a barrier between the plant and the invading fungus, and it inhibits spore germination. It has translinear action, that is, it is absorbed by the leaf and moves around using the leafs circulatory system it can also be used as a systemic. When it is applied to the irrigation water it is absorbed by the roots and delivered throughout the plant. Adding a 0.5% solution, about 1 teaspoon per quart, to the irrigation water will protect the plant from infection.

Neem oil is best used before the plant or the garden exhibits a major infection. By using it before powdery mildew appears, it prevents the spores from germinating. It should not be used on buds or flowers.

Oil Spray
Growers have used different oil sprays to prevent and cure fungal infections. Until recently most horticultural oil sprays were made from petroleum distillates. However, most organic growers have switched to using botanical oils. Aside from the safety factor botanicals such as cottonseed, jojoba, neem and sesame oils have fungicidal properties. They can be used in combination with other spray ingredients listed here. The oils are mixed at about 1-2% concentrations. A 1% solution is about a teaspoon per pint or 3 tablespoons per gallon. Add castile soap to help the ingredients mix. Oil sprays should only be used on the leaves, not the buds or flowers. Use weekly on new growth.

pH Up
pH-Up is a generic term for alkaline pH adjustors, used to increase water pH in indoor gardens. They come as either a powder or liquid. Its active ingredient is usually lye (KOH) or potash (K2CO3).

Fungi require an acidic environment to grow and die in alkaline environments. Changing the leaf surface environment from acidic to alkaline clears up the infection. An alkaline solution with a pH of 8 will make the environment inhospitable for the fungus and will stop its growth. This is one of the simplest means of controlling the fungus. It can be used on critically infected plants.

Potassium/Sodium Bicarbonate
Potassium bicarbonate (KHCO3) and Sodium bicarbonate (NaHCO3) are wettable powders that change the pH of the leaf surface toward alkaline. Another reaction takes place; the fungus cell wall actually bursts in the presence of bicarbonate. Potassium is one of the macro-nutrients used by plants and therefore is preferred over sodium, as sodium can build up in the soil. Sodium bicarbonate can be found in your kitchen (baking soda), so some prefer it for ease of obtaining. Both are more effective when used with an oil and spreader such as castile soap. They can be used to cure bad infections and prevents new ones.

Use one teaspoon of bicarbonate powder, a teaspoon of oil and a few drops of castile soap in a pint of water, or 3 tablespoons each potassium bicarbonate and oil and a half teaspoon soap in a gallon of water. Spray on new growth.

Serenade and Sonata
Serenade and Sonata are composed of different bacteria. They use different pathways to stop mycellial growth. They are considered totally safe to humans and animals since the bacteria attack only fungi. Watch out if you are a mushroom, otherwise you are safe. The two bacteria work well together.

They are easy to use, quite safe and effective.

Sulfur
Sulfur has been used to control powdery mildew for centuries. Sulfur sprays can be used indoors but they are not popular because of residue that remains on the plant. In greenhouses gardeners use sulfur vaporizers that heat elemental sulfur to the point of vaporization. The sulfur condenses on all surfaces including the leaves. A fine deposit of very low pH sulfur granules covers the leaf surfaces. The low pH environment inhibits fungal growth. The heaters use a 60 watt light bulb to heat sulfur which is held in a container above the light. The bulb supplies enough heat to evaporate the sulfur, but not enough for it to ignite. The problem with vaporizers is that they also leave a fine sulfur film on the leaves and flowers.

Active mildew: 7 to 8 hours per night 1 to 2 times a week.
Preventative maintenance: 4 to 5 hours once a week

Vinegar
Apple cider vinegar is toxic to powdery mildew because of its high acidity (low pH). Use it at the rate of 1 tablespoon per quart of water several times a week . Some gardeners recommend alternating using vinegar with potassium bicarbonate and milk.


PREVENTION

•Isolate all new plants in a separate area where they can't infect other plants.

•Filter incoming air to prevent spores from entering the room in the airstream.

•Install a germicidal UVC light, like the ones used in food handling areas. The light is fatal to all airborne organisms passing through the appliance. This will kill powdery mildew spores that are airborne.

•Spray the leaves with neem oil weekly. Neem oil presents both a physical barrier and a chemical deterrent.

•Cinnamon oil and cinnamon tea can also be sprayed as a powdery mildew preventative. If you are using cinnamon oil use 1 part oil to 200 parts water. (1 teaspoon oil in a liter of water.)

 

[Lazyman]

Montana, nice effort, but none of those actually KILL PM, they only kill surface spores, and require frequent sprays, which also further the PM infestation in flower and can lead to bud rot.

Eagle20 is safe for edible crops, and only requires one application to kill the fungus permanently. I'd rather use something strong once, early, and know my plants are happier and healthier than those that had their PM symptoms masked by some ineffective home remedy. Same goes for bugs, use Floramite or Forbid once or twice and know the bugs are all dead, or spray on some pyrethrins 17 times and hope for the best?

 

[Shcrews]

Montana, nice effort, but none of those actually KILL PM, they only kill surface spores, and require frequent sprays, which also further the PM infestation in flower and can lead to bud rot.

Eagle20 is safe for edible crops, and only requires one application to kill the fungus permanently. I'd rather use something strong once, early, and know my plants are happier and healthier than those that had their PM symptoms masked by some ineffective home remedy. Same goes for bugs, use Floramite or Forbid once or twice and know the bugs are all dead, or spray on some pyrethrins 17 times and hope for the best?

i agree with your post, but must say that Floramite is overrated while Pyrethrum is underused IMO.. i havent seen a spider mite in months.

back on topic.. a one-time cure is better than constant care. peroxide and milk are effective for about a week, then the PM comes back with a vengeance

however i have never gotten bud rot from spraying nugs with a peroxide solution.

 

[Guest3498]

Montana, nice effort, but none of those actually KILL PM, they only kill surface spores, and require frequent sprays, which also further the PM infestation in flower and can lead to bud rot.

Eagle20 is safe for edible crops, and only requires one application to kill the fungus permanently. I'd rather use something strong once, early, and know my plants are happier and healthier than those that had their PM symptoms masked by some ineffective home remedy. Same goes for bugs, use Floramite or Forbid once or twice and know the bugs are all dead, or spray on some pyrethrins 17 times and hope for the best?

Bingo!

 

[Lazyman]

i agree with your post, but must say that Floramite is overrated while Pyrethrum is underused IMO.. i havent seen a spider mite in months.

back on topic.. a one-time cure is better than constant care. peroxide and milk are effective for about a week, then the PM comes back with a vengeance

however i have never gotten bud rot from spraying nugs with a peroxide solution.

I understand, I believe scale has to be taken into account too, but honestly, who wants to worry twice a week about spraying even 4 plants? Don't you have anything better to do? i know i do!

With 120 plants in veg, 300 in pre-veg, and 140 in flower ALL the time, I have to be very efficient in my methods so that problems are prevented, not just "dealt with" as they come along. Plants are usually much happier if they never suffer the stress of a PM or mite infestation, or the endless cures some gardeners insist on applying, and re-applying, and re-applying, et al.

I only have to spray my huge-ass garden once a month, and never have problems. I would hang myself if I had to spray them twice a week with anything! lol

 

[grapeman]

Honestly never looked too much into the temp thing except remember that there seemed to be a threshold where spores were deactivated. I dunno...if burning sulfur is part of the formula then why not just do that and forget about raising temps? Not trying to be a jerk.

The problem seemed always to be with bringing in infected cuts.



I never really did lick the PM thing...even with Eagle 20.

Heat is required to make the sulfer fume... usually at 90 degress or slightly more, which will kill mildew.

But honestly, if you used Eagle, or any other decent fungicide and you still had problems then you never got to the source of the underlying problem.

And you always dip clones brought from the outside in a fungicide before introducing them to your grow room. that's just common sense.