I'm struggling with powdery mildew on my zinnias, which are overcrowded and planted alongside cosmos. The sprinkler system also waters them from above, which I hear isn't great for preventing this issue. Any suggestions on how to tackle this? Thanks in advance for the help!
19 Answers
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You’re right about the close plant spacing and overhead watering being major culprits. Try to improve airflow around your plants, water them less often, and apply water directly to the soil instead of the leaves. For treating powdery mildew, hydrogen peroxide works wonders! Just dilute 3% H2O2 down to around 0.25% or 0.75% in a spray bottle and apply it every few days. That should help clear things up without damaging the leaves. And it's usually more affordable and less smelly than neem oil!
Neem oil can also help! I mix my concentrate with water in a gallon sprayer. I’ve been dealing with the same issue on my zucchini and pumpkins lately. Just make sure to spray in the morning or evening, not in direct sunlight, especially during peak sun hours. Good luck!
Thank you!
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I’ve had success with diluted milk as well! But honestly, the best prevention is good cultural practices and choosing resistant plant varieties. I had to give up on Monarda in my yard, but I know there are some mold-resistant options out there.
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Thank you so much!