white powder mildew

ziggz311

New Member
whats up with WPM ? I ran into it last fall..got rid of all plants and bleached and painted room..back up and growing again and had a couple timer issues so would minor stress be the cuase for it to return ?
 

Southerner

Well-Known Member
Nah not stress...it's the environmental conditions. What is your rooms humidity during day and night? How much fresh air is the room getting? Are you using circulating fans? Do you have an appropriately sized exhaust fan?
 

ziggz311

New Member
humidity stays between 50-60..got central air comin into room..one fan..no exhaust! been running with that set up for many yrs. nvr seen WPM until last fall.
im keepin it in check with frequent spraying of green cure..really dont want to deal with this anymore!
 

SeanyMac

Member
I don't think minor stress would be the cause unless the plant already had it in it's system to begin with. Once a plant has it, it has it for good - even clones from mothers. So if you're buying clones somewhere it may be the mom. Humidity is usually the issue and/or not enough circulation. It's a huge pain in the ass for indoor grows for sure.
 

ziggz311

New Member
yes it is a pain in the ass. I started over from seed and it still came back. I suppose i ll try more circulation!! thanks for the input!!
 

justanotherbozo

Well-Known Member
...Southerner is right bro, pm spores are ubiquitous so if the conditions are right, mildew arises. ...airflow is key, if you don't have good airflow you're in trouble.

btw, a cheaper alternative than the green cure is milk, and any kind of milk will do, you jut dilute it down to like 10 to 1 and thoroughly spray your plants down and you'll be amazed as you watch the pm disappear, unfortunately it won't eliminate the pm until you fix your environment.

anyway, below i've included some info on milk as a fungicide so you can see there is actual science behind it and not just some old stoner bullshit.

peace, bozo

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Milk is a useful fungicide in the garden, and is more effective than standard chemical brands.


Researchers believe the potassium phosphate in milk boosts a plant's immune system to fight the fungi.

Where most organic gardeners use a baking soda, soap and oil solution, milk may be substituted to combat the unwanted fungus.

Preparing a Milk Solution and Spraying Schedule

The correct dilution and spraying schedule for garden plants depends on the situation and takes some trial and error.

A milk fungicide solution can range from 1 part milk to 9 parts water, to a strong, milk-only solution. A 1:1 dilution may work for a week, but a 1:8 solution requires spraying every 3 or 4 days.

Skim milk may work better than whole milk, as the higher fat milk may clog a sprayer; even reconstituted powdered milk works.

Uses for Milk Fungicide

Milk was originally used in the garden to treat powdery mildew on squash plants. It is now also commonly used on flowers such as rudebekia (Black-eyed Susans) and Begonias to cure powdery mildew.

Milk has also been used to cure Botrytis on a Cyclamen houseplant. This was applied full strength every morning (leftover breakfast milk). Rotten leaves were picked away and the plant pulled through with no more Botrytis.

Black spots and rust on roses can be controlled but not cured with milk. Fortunately, milk can prevent the spread of these fungi to other plants and new leaves. This can be very useful when bringing home a plant from the nursery and finding a black spot.


The copyright of the article Milk as a Garden Fungicide for Powdery Mildew, Botrytis, and Black Spots in Organic Gardening is owned by Deborah Turton. Permission to republish Milk as a Garden Fungicide for Powdery Mildew, Botrytis, and Black Spots in print or online must be granted by the author in writing.


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by Arzeena Hamir
Powdery Mildew

Less than 3 years ago, researchers in South America discovered a new alternative to controlling powdery mildew. Wagner Bettiol, a scientist from Brazil, found that weekly sprays of milk controlled powdery mildew in zucchini just as effectively as synthetic fungicides such as fenarimol or benomyl. Not only was milk found to be effective at controlling the disease, it also acted as a foliar fertilizer, boosting the plant's immune system.

Powdery mildew in the cucurbit family is caused by the organism Sphaerotheca Fuliginea. It is a serious disease that occurs worldwide. For decades, organic gardeners had to rely on making a spray from baking soda to control the disease. Now, instead of measuring out the baking soda and combining it with a surfactant (a "sticking" substance) of either oil or soap, gardeners need only head for their refrigerators.

In his experiments with zucchini plants, Bettiol found that a weekly spray of milk at a concentration of at least 10% (1 part milk to 9 parts water) significantly reduced the severity of powdery mildew infection on the plants by 90%. While some gardeners may be tempted to increase the concentration of milk for more control, Bettiol found that once concentrations rose above 30%, an innoccuous fungus began to grow on the plants. How does milk control powdery mildew?

Scientist aren't 100% sure how milk works to control this disease. It seems that milk is a natural germicide. In addition, it contains several naturally occurring salts and amino acids that are taken up by the plant. From previous experiments using sodium bicarbonate, potassium phosphate, and other salts, researchers have found that the disease is sensitive to these salts. It is possible then, that milk boosts the plant's immune system to prevent the disease.

Milk used around the world
The benefits of using milk to control powdery mildew haven't been isolated to Brazil. Melon growers in New Zealand are saving thousands of dollars every year by spraying their crops with milk instead of synthetic fungicides. The melon growers in New Zealand have been so successful that the wine industry is taking notice and beginning experiments using milk to control powdery mildew in grapes.

What kind of milk should be used?
In Bettiol's original experiment, fresh milk was used, straight from the cow. However, this is obviously not feasible to most home gardeners. The research work in New Zealand actually found that using skim milk was just as effective. Not only was it cheaper, but the fact that the milk had no fat content meant that there was less chance of any odours.

Wagner Bettiol's original article was published in the journal Crop Science (Vol. 18, 1999, pp. 489-92).
 

thegreensurfer

Well-Known Member
I used to get it bad, what fixed it for me was having my light cycle on during the night and off during the day. This way there isn't a temp drop during nighttime, preventing condensation, it keeps the temp & humidity more constant. Condensation is known to support germination of PM spores.

Also make sure your leaves are blowing around enough to prevent them from touching, if there isn't enough circulation and leaves are allowed to sit on another the transpiration from the underside of the upper leaf can cause condensation on the top of the lower leaf, this combined with the shade it produces will increase risk of PM.
 

Dr. Who

Well-Known Member
Try horsetail tea! yes an herbal tea, but it REALLY works at all stages of growth and I learned that here.

Drop the humidity down to 40-50 % it helps lots.
 
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