Powdery Mildew - Can I use two different fungicides?

zeppobird · Sep 30, 2019

Hello:
I believe I'm in the beginning stages of powdery Mildew. I sprayed with Baking soda once last week but I had to go out of town. I just rec'd some Dr. Earth fungicide which i sprayed on last night. I also have some Green Cure. Can I use the Green Cure after the Dr. Earth? And how often to use these fungicides without hurting the plants?

Thanks!

NeWcS · Sep 30, 2019

Yes, it is best practice to alternate products/ingredients when treating for pests and problems. I like once a week

CanadianJim · Oct 1, 2019

Green Cure is potassium bicarbonate, what's in the Dr. Earth?

zeppobird · Oct 1, 2019

CanadianJim said:
Green Cure is potassium bicarbonate, what's in the Dr. Earth?

Active ingredients: rosemary oil, clove oil and peppermint oil.
Inert ingredients: carrageenan, cellulose, citric acid, citrus pulp–orange, glycerin, vitamin c, water and yeast.

Mohican · Oct 1, 2019

Lemon juice diluted in water works.

Renfro · Oct 1, 2019

Mohican said:
Lemon juice diluted in water works.

Thats bad, lemon juice is acidic and that promotes PM. You want an alkaline environment to prevent PM. Thats why Potassium Bicarbonate and Sodium Bicarbonate work so well, they raise the pH not lower it.

I personally mix ALL foliar applications at a pH of 7.5 - 8.0. This slightly alkaline mix won't cause PM if foliar feeding.

I have even seen PM growing on the top of soil or rock wool when the conditions are favorable as the media is slightly acidic.

The best way to prevent PM is to control your environment. There is NO reason to have PM in a climate controlled grow. Allowing lights off temperatures to drop can cause PM because the cooler air holds less water and the RH% spikes. Sometimes it's just as simple as making sure the AC turns off when the lights go out.

Sir Napsalot · Oct 1, 2019

Renfro said:
Thats bad, lemon juice is acidic and that promotes PM. You want an alkaline environment to prevent PM. Thats why Potassium Bicarbonate and Sodium Bicarbonate work so well, they raise the pH not lower it.

I personally mix ALL foliar applications at a pH of 7.5 - 8.0. This slightly alkaline mix won't cause PM if foliar feeding.

I have even seen PM growing on the top of soil or rock wool when the conditions are favorable as the media is slightly acidic.

The best way to prevent PM is to control your environment. There is NO reason to have PM in a climate controlled grow. Allowing lights off temperatures to drop can cause PM because the cooler air holds less water and the RH% spikes. Sometimes it's just as simple as making sure the AC turns off when the lights go out.

You can control the climate outdoors? Neat!

Renfro · Oct 1, 2019

What you want is a product called actinovate. It would be best applied before as a preventative though.

ganga gurl420 · Oct 2, 2019

Renfro said:
Thats bad, lemon juice is acidic and that promotes PM. You want an alkaline environment to prevent PM. Thats why Potassium Bicarbonate and Sodium Bicarbonate work so well, they raise the pH not lower it.

I personally mix ALL foliar applications at a pH of 7.5 - 8.0. This slightly alkaline mix won't cause PM if foliar feeding.

I have even seen PM growing on the top of soil or rock wool when the conditions are favorable as the media is slightly acidic.

The best way to prevent PM is to control your environment. There is NO reason to have PM in a climate controlled grow. Allowing lights off temperatures to drop can cause PM because the cooler air holds less water and the RH% spikes. Sometimes it's just as simple as making sure the AC turns off when the lights go out.

Very true... well except for the control of the outdoor environment.

Renfro · Oct 4, 2019

ganga gurl420 said:
Very true... well except for the control of the outdoor environment.

Lol yeah, very much indeed. I get high and sometimes get lost on what forum section or thread I am in. I apologize.

Rob Roy · Oct 4, 2019

I've had good luck controlling powdery mildew with sulfur spraying. Side benefit is it messes up spider mites too.

It's available in concentrated liquid or as a powder (which you dilute) at big box stores and garden supply places. Many brands have pyrethrin added. So wear a dust mask. I add a few drops of Dawn for a surfactant. If you overdo it, it can burn plants. Wouldn't spray seedlings or young clones with it either. Wouldn't use after the 3rd week in flower, maybe even the 2nd week depending on bud formation etc.

Outdoors I use alcohol and try not to hit the buds.

WolfScott · Oct 9, 2019

I had really good luck combating powdery mold on my outdoor plants this year with this product (see photo). Last year I got it real bad and had to harvest early. This year I used this product as soon as I noticed a little powder on the fan leaves and it seems to stop it right away.

GreenLady99 · Oct 9, 2019

I used neem up until flower started and now I'm at a loss. I dont want gnarly tasting bud

707mend · Oct 10, 2019

Lemon juice is acidic but also is antibacterial and kills everything, so I could see it working

CanadianJim · Oct 10, 2019

H2O2 (hydrogen peroxide) will kill pretty much any mold, but as it breaks down into water it'll end up soaking your buds again. If you do it in the morning maybe the sun will dry them off, and if you're getting soaked with dew anyway I would say it's worth a shot. I also don't know if it damages trichomes or not.
For powdery mildew I use potassium bicarbonate, and it is also good for prevention of budrot. If you have a really bad pm infection you can wash your buds at harvest.

Powdery Mildew - Can I use two different fungicides?

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