Why do we mist?

[Team Ferret]

I was wondering why do we mist our orchids?

From what I have read, it is transpiration that brings water and nutrients from the roots to the leaves. Transpiration, which is the cooling mechanism of plants similar to perspiration in humans. Well, if there is water on the plant already, how can it transpire?

I do understand that there is a requirement of these plants, that there be some humidity around them and that the humidity should be higher as the temperature gets higher. So it seems appropriate to mist orchids that are outside and/or subject to higher temperatures, as this aids the cooling of the plant which is unable to transpire enough to cool itself, because the plant evolved in a different environment. Also, orchids grown in drier climates would need to be misted to slow transpiration and prevent dehydration. Now, this is based on my understanding of how plants work, but I am not a botanist. I have been just reading as many books I can get my hands on to learn more about how plants, specifically orchids, work.

So is there really a need to mist orchids that are not subject to high temp or low humidity? Would doing so slow the uptake of water and nutrients and thus slow growth?

Dave