From

Location

Message

Date Posted

Seattle, Washington

Ok, I keep hearing people say they use baking powder(or is it baking soda?) for powdery mildew. How do you use it exactly? Does it really work?? B. Mitchell

8/12/2003 3:03:09 PM

[email protected]

Baking Soda. Controls Powdery Mildew by interupting the environment the disease needs to live. In short, the baking soda alters the pH of the leaf surface making it unsuitable for the causal pathogen. By itself though, BS doesn't work very well. So it is added to a 1% Superior Horticultural Oil solution.

1 Tbsp of Baking Soda +
2.5 Tbsp of Superior Summer Oil
Per Gallon of Water.

Spray in the evening paying particular attention to the undersides of the leaves. Watch the oldest growth near the stump. That's usually the first area affected. Areas of reduced air circulation are of concern too.

Temps should be & stay below 85*F for 6-8 hours.

Because this cocktail contains none of the high quality surfactants that conventional fungicide have, you may need to reapply quite often. Like evry 3-5 days if it's been raining (hah!)

Steve

8/12/2003 4:22:08 PM

Garden State Pumpkins

if

8/12/2003 5:24:32 PM

derry n.h u.s.a.

Hi Steve:
I ended up getting "Compass"for the mildew it's a 1/4 teaspoon per gallon of water i will aternate with copper,once a week. Will the Compass kill the existing mildew?its not to bad,im keeping it in check with all the spraying im doing,but cant use the new stuff till it stops raining late tomorrow or early thursday. i did burn 5 to 8 leafs bad with the soda and oil it was hot and they were younger mid sized leafs. John

8/12/2003 7:44:15 PM

Montoursville, PA

John....maybe better to have a little damage than to see fuzzy white leaf winking at you. All fungicides I have ever used on anything has the potential to burn. I go a little light on label instructions. This is very neccessary when I use a sticker. Stickers sometimes increase the value of the associated spray material.

8/12/2003 8:33:13 PM

Monrovia,CA

Have you ever heard of adding household dish detergent as a sticker instead of the summer oil?
Thanks,
Michelle

8/12/2003 9:07:56 PM

[email protected]

Heard of detergent but haven't used it on vegetables of any kind. Goos for spreading. Bad for sticking. And no enhanced tissue penetration. This year I'm using a new organosilicone surfactant that is blowing away anything I've ever used before. Dwaine's using it too. Hawkeye. This is the worst year we've ever had for rain & humidity & yet for the first time in the 8 years we've been here, we have zero Powdery Mildew. Same fungicides too!

8/12/2003 10:10:05 PM

Monrovia,CA

Wow Steve, that's pretty impressive given your weather this season. I spotted the beginnings of powdery mildew on the leaves around the stump....which are slowly dying. I've been Really nervous about spraying...temps are in 100's again. I sevened some corn silks for earworm and fried them last week. Yikes! But I know the mildew has to be stopped dead in its tracks...so I thought I'd start with the baking soda..and go from there.

8/12/2003 11:28:32 PM