What's new
  • Please note members who been with us for more than 10 years have been upgraded to "Veteran" status and will receive exclusive benefits. If you wish to find out more about this or support IcMag and get same benefits, check this thread here.
  • Important notice: ICMag's T.O.U. has been updated. Please review it here. For your convenience, it is also available in the main forum menu, under 'Quick Links"!

White powdered mildew

Camillia

New member
Almost the end of the growing season, and half my crop has white powdered mildew. It’s been a long season and I want to roll into a ball with ice cream and cry. Is this fixable? I didn’t add pictures because no one needs nightmares tonight.
 

3illmesmart

New member
Milk is your best bet and is not to expensive or caustic. Mix 10-20 percent to water and spray bottom and top of all leaves. If stubborn you can do a second application.
Best outside or on a catch sheet because it will smell milky when you do it.
 

Douglas.Curtis

Autistic Diplomat in Training
Thoughts for next year should look at improving nutrition. A plant healthy enough to fight off pests is also healthy enough to resist powdery mildew. ;)

Rabbit manure has the highest micros and trace elements of domesticated animal manures. Higher than llama, alpaca, sheep, goat, pig, horse and significantly higher than most cow manure.
 

laszlokovacs

Well-known member
What are peoples thoughts on spraying with 1tbsp/gal baking soda and a bit of surfactant? Very popular in organic gardening often with H2O2 but i would skip the peroxide bc of its oxidative properties on the plants/trichomes.
 

Creeperpark

Well-known member
Mentor
Veteran
You can't fix what's already been damaged because that's done. However, you need to know what happened the cause and how to prevent it in the future. Most all growers learn about mold by getting it, and then learning how to prevent it.

High humidity and low airflow are the primary causes of white mold. Planting your vegetation without adequate spacing where it cannot get proper air circulation, or overwatering your garden or potting soil can create prime conditions for white mold to grow. Try using an oscillating fan to move fresh air over and through the plant canopy. Gentle airflow.

If you learned how to not have mold from this grow for the future, then having the mold can be good... 😎

 

Creeperpark

Well-known member
Mentor
Veteran
What pH can mold survive?
Although the majority of yeasts and molds are obligate aerobes (require free oxygen for growth), their acid/alkaline requirement for growth is quite broad, ranging from pH 2 to above pH 9. Their temperature range (10-35°C) is also broad, with a few species capable of growth below or above this range. Google
I did as you said! I have hope the rest of the season now. Thanks!
Potassium Bicarbonate has a pH of 8 and can damage the soil. So be careful.
😎
 

Hammerhead

Disabled Farmer
ICMag Donor
Veteran
If you don't have a stable environment that keeps temps, and humidity stable you will need to use IPM to keep PM out of your garden. It's not difficult to do.. There are many organic options that work well. You have to do this regularly. Keeping your indoor room at 78f with the lights on/off and with a 50% RH you will not see PM.

Outdoor is even easier using the same method. You might need to do it more often depending on weather conditions.,

Powdery Mildew grows when the temps and humidity change a lot between the day and night. The fewer these change the better. You should try to keep temps swings less than 10deg. Humidity has less of an effect but still try to keep it between 50-60 % during flowering. You could go lower 40-50%.. Plants like more humidity.
 

funkyhorse

Well-known member
If you don't have a stable environment that keeps temps, and humidity stable you will need to use IPM to keep PM out of your garden. It's not difficult to do.. There are many organic options that work well. You have to do this regularly. Keeping your indoor room at 78f with the lights on/off and with a 50% RH you will not see PM.

Outdoor is even easier using the same method. You might need to do it more often depending on weather conditions.,

Powdery Mildew grows when the temps and humidity change a lot between the day and night. The fewer these change the better. You should try to keep temps swings less than 10deg. Humidity has less of an effect but still try to keep it between 50-60 % during flowering. You could go lower 40-50%.. Plants like more humidity.
Hi there Hammer
I think the best is to find suitable strains for all the thermal conditions. The sativas of old were grown in rainforest environments. The modern bred sativas indoors in tiny 0,5 lt pots cant resist rainforest environments.
Genetics are clearly degraded
What is IPM?

My greenhouse environment has a very wide thermal oscillation and this is happening naturally here with cold and very humid mornings and warm/hot and drier afternoons ranging from 5c/40F to 35C/95F or hotter and 100% humidity in the mornings to afternoons of less than 50% humidity even going down to 30%

What I note is for indicas this environment is terrible, I cant grow indicas properly, they dont stand high humidity, they all rot and mold. So dont grow indicas with such an environment
On the other hand sativas thrive in high humidity areas but I still see full of PM problems.
The problem is where these sativas are being bred or kept

If they are being bred in a controlled indoor environment, rot and bugs problems are guaranteed and quality will probably suck because you cant select real sativas properly indoors, the only thing you can do with pure sativas indoors is a blind open repro to search and select in an outdoor environment
If they are being bred outdoors out of their native environment in the case of pure lines, then I find that sativa plants bred in very dry desertic environments like Spain have a lot of PM problems when they come back to high humidity areas and need to readapt, same goes for aussie strains
I have seen full of PM this year on Original Haze
I had 2 different Mangobiche lines this year. The one bred in Colombia no PM problems at all. The one bred in Spain was a PM festival, only 2 out of 6 grew PM free
 

Hammerhead

Disabled Farmer
ICMag Donor
Veteran
There are varieties that are more resistant to PM. Wherever you are (climate) has a lot to do with outdoor mold problems. If you are in a climate that is not hospitable to PM you won't see it often. If you are growing indoors the #1 reason for PM is high temp swings between lights on/off with large humidity swings. That's just a fact. I live in Cali where PM is very common and all growers deal with this. Growing in a greenhouse is not a whole lot different from indoors. Keeping your environment stable is a must. With the growing tech today PM shouldn't be an issue. The best preventative I've seen for an indoor/greenhouse grow is Nutrafog.

IPM=Integrated pest management..

 
Last edited:

Hammerhead

Disabled Farmer
ICMag Donor
Veteran
If your room environment is kept stable PM won't be an issue. This is what we all strive to achieve. If that's not possible using IPM or a sealed room are the options available. I use organic Corn and soybean oil in veg. All of your IPM should be done in veg. The healthier your plants are in veg the fewer issues you will see in flower. Billions of mold spores are floating about every day. It's not possible to get rid of them 100%. Your climate/environment will dictate what method you should use.
 

Douglas.Curtis

Autistic Diplomat in Training
Resistant plants are more efficient at extracting nutrients...
Well fed in veg (right balance of nutrients)...

One key is balanced nutrition. Balanced nutrition is significantly easier in living soils.

John Kempf points to the curcubit crop they planted in rows across dead soil and living soil. The living soil plants had no PM issues, even when their runners were growing across PM infected plants in the dead soil. Same plants, different nutrient absorptions, different health.
 
Last edited:

Hammerhead

Disabled Farmer
ICMag Donor
Veteran
Nutra fog, adds nutrients...
Resistant plants are more efficient at extracting nutrients...
Well fed in veg (right balance of nutrients)...

One key is balanced nutrition. Balanced nutrition is significantly easier in living soils.

John Kempf points to the curcubit crop they planted in rows across dead soil and living soil. The living soil plants had no PM issues, even when their runners were growing across PM infected plants in the dead soil. Same plants, different nutrient absorptions, different health.

Nutrafog uses a Pest mold agent. Where did you find info there agents have nutrients? They do not sell Nutrients yet. I'm sure they might be coming.

Neutra-Spore B are Hydrogen Peroxide and Peracetic Acid, Caprylic acid, Mono and di-potassium salts of phosphorous acid..
Neutra-Control A is:

  • Safe to use on clones until harvest
  • Non-phytotoxic
  • Safe to use around bees, ladybugs, and other beneficial's
  • Not harmful to the environment and can be used around pets and people
 
Last edited:

VenerableHippie

Active member
Almost the end of the growing season, and half my crop has white powdered mildew. It’s been a long season and I want to roll into a ball with ice cream and cry. Is this fixable? I didn’t add pictures because no one needs nightmares tonight.
I see you've applied a remedy but if you're outdoors Builders Lime (also called slaked, hydrated) can be used in two ways. Half tablespoon per gallon as a foliar ... and a light sprinkling of lime over the soil surface helps keep fungus/mould away.
Does so in my well-mulched gardens anyway.
 

troutman

Seed Whore
I have a container of Sulphur dust that I haven't used yet and it mentions powdery mildew as one thing it controls.
Better air flow along with narrow leafed strains will help. Some thick Indica bud types are prone to mold unless
you have very low humidity during flowering.
 
Top