Hello everybody.
We have two monsteras at work, which were overwatered and having issues with powdery mildew.
So I decided to treat them both with a spray of baking soda ( 3 tablespoons + 1 drop of olive oil + 1 drop of liquid soap).
Three days had passed but the leaves seems to get worse.
For information, the soil is still humid and I cant do a thing about it (dehumidifying it or removing rotten roots )
Did I use a very concentrated solution ?
Should I mist the leaves and wipe them gently ?
what to do ? please help.

first plant






seond plant

Hi. The yellow/rust-colored spots on the leaves you see are the result of overwatering: it could degenerate into root rot or it could just be cosmetic but right now all you can do is keep an eye on them and make sure no water is allowed to stagnate in the undervase.

Now let's get to the powdery mildew. I don't see any on it right now. What I see is staining on leaves due to the home-made remedy you used. Don't worry: it's purely cosmetic. Just use an ordinary household sponge with warm soapy water and they'll clean away. In case you should have definite powdery mildew problems, please leave the Internet remedies alone and get some water-soluble sulfur. It's cheaper than hamburgers on a weight basis, it's pretty much non-toxic, if stored properly it has no expiration date and, much more critical, works really well on powdery mildew.

Powdery mildew?? On a Monstera?? @Gina 1960

Spider mite stippling could look like powdery mildew. Or just dust? Hard water spots? Who owns the plants? In the future, maybe try plain water first. Those home remedies can be sketchy & some can damage some kinds of plants.