Hey howzit? Sorry for the slow reply. Hopefully you checked Google for this answer and didn't wait for an answer. I just got some powdery mildew for the first time during the last couple weeks. It was really hot and humid with no wind. So, obviously I'm not an expert on this and had to look up some info on this too. Here's some of the things I found:
- Make a solution of 2 teaspoons organic apple cider vinegar per quart of water. Spray on the plants to eliminate and/or prevent mildew growth.
- Add ½ teaspoon baking soda per quart of water. Spray.
- Oil sprays consisting of neem oil, sesame oil or fish oil work on powdery mildew as it does on many fungal diseases.
- Milk sprays have been very effective in eliminating powdery mildew. Combine 40% milk with 60% water. The milk’s protein acts with the sun to create a natural antiseptic, killing mildew as the result. Milk sprays should be applied in bright light every ten days as a preventative measure. This method can be employed to resist mildew on any garden plant.
- Cinnamon oil, garlic oil, coriander oil, clove oil, jojoba oil, cottonseed oil sprays.
- Applications containing copper, available at any garden center.
- Hydrogen peroxide added to water (1 tablespoon per gallon) oxidizes the fungus cell walls, killing it.
- Limonene (oils extracted from citrus rinds) mixed with water at the rate of one teaspoon per pint offers fungicidal properties and will aid in control, but not eradication.
- Sulfur burners as a means of control. Stay out of the area when using this treatment as it can cause respiratory inflammation in humans. Follow directions and wipe down all walls and windows when completed to remove any residue.
Also Mandala Seeds website says lecithin sprays, and baking soda sprays and garlic extract, but didn't give ratio instructions. Potassium bicarbonate is supposed to work too. And I'm pretty sure a guy I know sprays kombucha on his plants to fight powdery mildew. He also said kombucha is one of the best things you can spray on your plants in general and that guy can grow some super healthy trees so I tend to believe what he says.
I don't think I would necessarily endorse all of these, but it's what I found with a quick search
I've used milk sprays for powdery mildew on my pumpkins, cucumbers and something else that is prone to powdery mildew, but I can't remember what it is right now. The milk spray works, but I think I was mixing it 2 parts water to 1 part milk so a little less than the above ratio recommendations and it was working good. I think I'd try the vinegar spray before milk though. I'm not sure I want to spray milk on my plants.
Anyway, let us know how it goes and what you decided to try.
