With the damp spring and summer we had, some powdery mildew was almost inevitable. Question was, where was it going to hit? The vegetables like squash, cucumbers, zucchini, or tomatoes, or the flowers like zinnias, sunflowers, or phlox? Almost every plant is susceptible to this common set of fungi. On most plants, it looks like a thin layer of dust, on others like tomatoes , it can cause yellow splotches on leaves. No matter what it looks like, if bad enough of an infection it can kill the plant.
The best way to deal with powdery mildew is by prevention. Use mildew resistant varieties, don’t overcrowd plants, and be sure there is enough air circulation. If your plants do get infected, remove the infected plant parts, thin out the plants to improve air circulation, don’t water plants from above and try treating with a chemical fungicide or an organic method like neem oil, or what I tried, a milk and baking soda solution.
This year it was my summer squash and zucchini that became infected with powdery mildew. I may have overcrowded my plants a little bit, well maybe more than a little bit, so I was almost inviting the mildew into my garden. By the time I started to deal with the issue, I had a full blown powdery mildew infection.
Since the powdery mildew was in my vegetable garden, I especially didn’t want to use a non-organic way to treat it. First I got rid of as many of the badly infected leaves. As I did this, I found that the leaves were truly covered in a thick layer of dust that flew everywhere as soon as I handled the leaves. Yuck.
Once that was done, I needed to spray with some kind of fungicide. Other than chemical means, there doesn’t seem to be a lot of evidence that anything else really works well. After a lot of research, I settled on spraying with a milk and baking soda solution.
I used:
2 cups water
1 cup milk (I used 2% but anything would be fine; it’s the milk protein, not milk fat that is the active ingredient)
3 Tbsp baking soda
squirt of Dawn dish detergent
Stir and put in some kind of spray bottle.
Spray on all infected and uninfected leaves every 10-14 days.
After 2 weeks, many of the leaves were looking much better.
Unfortunately, the plants that were severely damaged ended up dying. But, the ones I was able to rescue seemed healthy and have continued to put out squash and zucchini.
Next year, I need to be sure to get on top of this earlier. Isn’t that true for many garden issues? I had success with the milk and baking soda solution on the less infected plants and will use it again next year if the powdery mildew comes back. Many of the plants that failed were severely affected by the time I even started trying to do anything. Again, early intervention is the key!
Did you have any powdery mildew issues this year? How do you treat it?
What a shame to have such damage on your edible garden. I get powdery mildew on my phlox paniculata every year.
I usually get some on my phlox as well. Doesn’t seem to affect them too badly, just makes them a little unsightly.
Good post. I get powdery mildew on my Monarda almost every year. I pretty much just live with it. It doesn’t really harm to plant and doesn’t come until late in the season. You’re right that the focus should be prevention.
I have it on my Monarda as well, but like yours, doesn’t seem to harm the plants too much. Comes late as the garden is waning, so not too noticeable either. I wonder if I sprayed at first sign they might bloom longer?
I use milk and water spray and it does help in the veg garden…but it will keep going on other plants that don’t seem affected by the output of blooms…but the veg garden it can be fatal. Glad to see yours rebounded.
I’ve never had it this bad in the vegetable garden before. Some here and there on the flowers and maybe mildly on the vegetables. Glad the spray works for you too. It sure is easy enough to do. I was sorry to lose all those plants, but glad I got some to survive. Will try again next year.