Is misting beneficial?
 

Does it help the plant? When would it be appropriate to mist, and when is it not appropriate to mist? How much does it increase the humidity?

It doesn't significantly affect humidity for more than a minute or two. I would only do it if there are aerial roots - they can use the water and won't get it if you just water in the pot. Otherwise, it doesn't help and could spread pathogens. When you water, water well which brings air into the root zone and flushes fertilizer salts, hard water salts, and general crud.

Ray, who posts on the Board often, points out that these don't suffer from too much water, rather from lack of air in the root zone (which you get if the mix is old and broken down) With fresh and free-draining medium, nearly impossible to overwater.

To increase humidity, the only things that work are:

• Humidifiers;
• Having lots of plants together;
• Having lots of animals in the house, including people.

Things that don't increase humidity are:

• Misting;
• Trays of water with or without pebbles near the plants.

I agree with Roberta and ES that misting does not help increase humidity. With that understanding, I am someone who mists the abundant aerial roots of my plants each and every time I water, which is frequently, because mine are all potted in large bark. I found early on that if I did not do this, those beautiful aerial roots quickly dried up and withered in my home. So I do it not to increase humidity but simply to provide moisture to those roots which they would not get otherwise. I think of it as them getting "rained on" a few times a week.

Mounted orchids appreciate misting if it wets their root zone but, otherwise, I have to agree with what others say. The water does not stay in the air long enough to be of benefit.

Another way to increase humidity...Aquarium or container pond....

Just a caveat to the good advice already given...

Within an enclosed greenhouse / grow room, misting can increase humidity. During warm days in my basement orchid greenhouse I lightly wet all my plants in the early afternoon when temps get near the max (85 f). This usually jump humidity by 10% and also cools the room a couple degrees (evaporative cooling). I agree misting a plant in a large room is pointless however (unless you are wetting copious air roots also).