Can it really be detrimental to the plant? I've always thought the benefits were probably exaggerated but I was unaware of possible problems from misting.

Salt deposits from hard water would A) dehydrate the leaves B) clog the pores

Misting...or keeping the foliage wet (even just overnight) can lead to bacterial and fungal problems as well.

If it is a fairly closed environment then it can raise the humidity. I have most of my plants in enclosed porch and misting can increase humidity. I do it when it is warmish (65+) and I also have a fan so that the water does not sit/pool in one place too long - to avoid fungal problems. Few plants that are more prone to spider mites, the misting the leaves (especially the undersides) every now and then keeps them at bay.

It would have to be a very closed area, or one with minimal air flow or no forced air heating/cooling, or a LOT of mist being applied, or it being applied VERY frequently for misting to make much of a difference in the average home environment.

I have trees in a south facing bedroom and in my foyer. No misting. My trees in my sunroom don't get misted either. It is a closed room with no return air. If there is humidity in the room, it is from the moisture in the soil. Trees are doing well.

Agreed - Average home environment it will not work.

My porch is basically closed system with a window kept half open on the house side. The lowest it gets there is about 30-35 RH when inside house may be in teens. Our max indoor temp is set at 66F for mornings and evenings and 62F for night. It is hot water radiant heating for the house so that helps a lot. Being an attached porch it benefits from the heated house.There is a electric radiant heater in the porch but that only kicks in when it drops below 50F.

When it is warm outside and sunny, temp inside the porch rises to 65-75F during winter. If I mist all my plants there one round humidity will rise to about 70 RH and settle back at 60 RH for a day or two. The plants are also giving out water in this area so that keeps it up too especially when it is warm and the plants are active. The only air exchange that is happening is through the window (passively) and when the door to the porch from inside is open. If it gets over 75F I try to keep the door fully open so some of the extra heat can escape into house.

When I had my plants in the basement, I had it enclosed using plastic sheets hung from the joists to the floor but open on the top to the joists. Although not as effective as the porch but a morning mist would sort of carry through for about 5-6 hrs. But mostly I depended on a small computer fan blowing over a tray of water 24x7. I could maintain a minimum of about 35 RH.

I haven't had any fungal issues whatsoever, and spider mites are definitely kept at bay. I mainly see mites when I don't mist/wash and occasionally temperatures rise too much. My mist is essentially almost a wash. I'm growing various things besides citrus under lights in a cellar (more than half the ceiling height is below legal street grade) with a concrete floor......humidity non issue - always some dampness in a cellar with exposed water piping and steam heat.......but I also use a fan.

I was just thinking about where citrus is grown in southern CA as well as in the Sacramento Valley where I lived for over 20 years. California typically doesn't get any rain from May through September and has virtually no outside humidity. California has dry heat. I remember driving through orange groves in Hemet as a preteen. That area is very close to the desert terrain as it's near Palm Springs. Since water is so precious down there and expensive, do you think the farmers mist their trees? I do not understand why so many people think citrus needs humidity. I have not found that to be true as my trees have been inside since October. I have not done anything to my trees except water and be sure they have as much natural light as possible. I have flowers, new growth and some fruitlets on my trees.

I do not mist

I never do.

Neither do I.

not a mister

I have past winters but have not this winter....I notice no difference.

If I have nothing to do, I'll give my plants a good misting but if I forget a few days, no big deal either. I believe it temporarily slightly increases humidity around the tree and that the tree sucks the water in through its leaves. Regardless, even with a good misting, it's dry within a couple hours if not sooner so no bacteria issue there either.

In normal indoor condition misting is not going to increase humidity by any reasonable amount. But misting the leaves, especially underneath, every few days can make the life of spider mites very difficult.

Because my house is really dry during winter months I used to mist but it never seemed to be enough. This year I'm using humidifiers in the middle of my plant areas. The two challenges are mites and low humidity due to heating system type I guess. I believe that some of my early years winter leaf drop was all because of low humidity in this house.

I am actually misting consistently for the first time (as a test), with one set of trees - the ones I have in my front bedroom (6 of them are up there in front of either window).

My house is completely central air (heat and AC) - something that I am still learning how to deal with after almost 55 years of living with circulated-water heat prior to moving here. I have a couple humidifiers in my living room including a larger "whole house" (ha!) one that I positioned near a close-to-the-floor intake. That bigger one has managed to shunt some humidity upstairs to the back bedroom, which is directly above where it is (and is where I sleep, although I have an optional humidifier there if needed) but not so much makes it to the front, which is also SW-facing and does heat up year round.

Without any supplemental humidification, the house gets down into the 10% - 18% RH range - especially during cold outbreaks, which is insane. The humidifiers have helped to at least get it up to the mid-upper 30%s and higher (I try to aim to get it to the 40% - 45% range as optimum but will take what I can get).

Last year I ran a humidifier in the basement too for the trees there but haven't needed to use it yet this year - partly because we have had so much rain the past year. Plus by having less citrus down there (4 instead of 5), it hasn't been as bad there yet as there is more air-circulation around them (at least so far, although I don't want to jinx it). Almost all of my non-citrus overwintering tropical/subtropical plants are also down there too nearby so there is more potential to have "moisture" by just having more plants in the general area that are getting watered. I have 6 temp/humidity probes all around the house and basement to get a general idea of where things stand as a note.

In any case, I have put all of my trees up on short plant stands (the Australian red center lime is on a tall stand) positioned inside some Home Depot "mixing troughs", and when I water, whatever comes out lands on the pot's plastic saucer just underneath in the trough, and excess in those can overflow directly out into the trough providing some "bottom humidity" as it evaporates.

Denise you may not check out monthly humidity levels in Hemet, CA here: https://weather-and-climate.com/average-monthly-Humidity-perc,hemet-california-us,United-States-of-America

It rarely goes below 60% there.

In cold areas indoor humidity can easily drop into the teens. Misting is a poor way of raising humidity unless the plant area can be closed off. In a normal household even a humidifier will have a hard time keeping up with it.

Since you keep your plant room on the cool side dry air it is less of a concern since water demand on the plant is also considerably less. In fact keeping it cool and humid will be detrimental since it will encourage fungal activity.