Does misting actually help?

Does misting your plants actually help the ones that require humidity? Isn't it like licking your lips makes them drier?

It helps!! It gives them humidity, and also helps reduce dust buildup. I notice a real difference in the health of my plants when I mist them on a daily basis.

This will be an everlasting debate - some feel it does help and some feel (and will argue incessantly) that it doesn't.

I do mist some of my plants when I remember to, mostly Tillandsias, other Bromeliads and Dischidias, but also other plants with aerial roots.

What I find most helpful for plants that require a lot of humidity is to mist the top portion of the soil.
With that, your'e adding a fair amount of water to provide evaporation, (more than you would by just misting the leaves) and you're also adding necessary moisture for those plants with those fine 'feeder' roots that are at the top of the soil.
I'm not saying that's a scientific fact - just my opinion.

I personally view misting as pretty much futile when raising humidity is the goal; and there are some compelling reasons, rooted in plant physiology, why we may wish to reconsider the habit/practice of misting, even if we set aside the fact that it helps for only a couple of minutes and has no residual benefit. In passing, I'll also mention that we should consider the possibility that water from misting, dripping from leaf to leaf or plant to plant, will carry and spread insects and other pathogens, especially fungi. Misting does help satisfy the nurturing side of growers who adhere to the practice, though. ;o)

There is something very important about misting that no one EVER mentions on these forums. In many, probably more than half of all plants, exposure to rain causes rapid suppression of photosynthesis by inducing stomatal closure and causing temporary decrease or cessation of the photosynthetic mechanism. Examining plants exposed to several minutes of misty rain often reveals complete stomatal closure within 2 minutes, with a 30-40% decreases in photosynthetic ability within 1 hour. In addition, it often takes many hours to several days for plants to return to a "pre-rain" ability to carry on the efficient business of photosynthesis.

Moisture on leaves and/or in the air surrounding plant foliage will determine the humidity difference (gradient) between the inside of stomata and outside of the leaf (this is termed the saturation deficit). Humidity level just inside stomata is usually very high as they are normally full of water vapor, which will move out rapidly if there is a steep concentration gradient in humidity, i.e. if the surrounding air has low humidity. This causes a drop in turgor which closes stomata. If you equalize the gradient, or raise surrounding (relative) humidity, turgor remains constant so stomata remain open.

Misting:
Some discussion of "diffusional resistance", or things that slow down the diffusion which would occur naturally based on the water vapor concentration gradient (slow water loss through leaves) is required to understand the effect of misting. Primary considerations: the "stomatal pore" and the "boundary layer". Most, (almost all) transpiration occurs through the stomatal pores. We already saw that plants slow water loss by closing their stomatal pores when water is in short supply, but it occurs when something slows transpiration as well.

The blanket of unstirred air on the outer surface of the leaf is called the boundary layer. It helps insulate the leaf against water loss because it becomes nearly completely saturated with water vapor. The thickness of the boundary layer might only be a few thousandths of an inch, and depends, in part, on the degree of air movement, which blows away the boundary layer. If there is no air movement, a thicker layer and slowed transpiration results. More wind gives a thinner layer and rapid transpiration. At high wind speeds, the stomata usually close to prevent this rapid water loss (see above).

You can see examples of how the boundary layer works in cacti and plants that are pubescent (hairy). Most are slow-growing. I have read that the primary reason, indirectly, is stomatal closure due to the more effective boundary layer slowing transpiration and thus slowing photosynthesis.

So - we’ve seen that rain or mist on leaves obviously slows water loss from foliage by making (near) perfect the boundary layer. Since this slows transpirational loss, it closes stomata and also slows photosynthesis, which is not a good thing.

Even though we may not be able to expect the a negative impact on every single species of plant, I have concluded (for my own purposes) that an increase in relative humidity in air surrounding the plant is the most effective way to keep stoma open and insure optimum photosynthesizing ability and vitality. Remember, that there are abundant other factors that influence stomata function - light, temperature, internal plant rhythms all play into the equation, but far more plants will experience reduced photosynthetic ability when exposed to rain or mist than will not.

Al

ok---but, since most house plants are tropicals, don't they usually come from places that get a daily rain?

But tropical places dont necessarily get a daily rain. I have been in tropical areas and saw nary a drop of water coming from the sky!

what if they are in an enclosed area (an atrium) and the misting increases humidity --i can understand that maybe outdoors the misting would just evaporate and maybe indoors some too but when i went to indoor gardens in washington d.c. there were some very humid parts for certain plants

what if they are in an enclosed area (an atrium) and the misting increases humidity --i can understand that maybe outdoors the misting would just evaporate and maybe indoors some too but when i went to indoor gardens in washington d.c. there were some very humid parts for certain plants

sorry for the triple entry!! thought it didn't work first times! am computer challenged!

You'd probably be better off with a humidifier ( if like me you are in a cold climate and it is very dry inside in the winter ) or having water in the room - maybe an indoor fountain or just pepple trays with water under the plants. I doubt the high humidity in some of those indoor gardens comes totally from misting.

I'd also be surprised if those humid indoor gardens use misting to get the humidity up--when you mist, the water droplets are fairly large and aren't going to stay airborne for very long, it's the teensy droplets that stay up in the air that create humidity. I'm sure they have something more along the lines of a giant humidifier.

I used to mist my plants when my collection was quite small but really didn't see any benefit. Humidifiers are good but they are constantly running out of water so I abandoned those a couple of years ago. Pebble trays are similar to humidifiers in that they need constant replenishing but I prefer those to humidifiers - they are easier to fill up and humidity is higher around the plant with this method before evaporating.

If your plants are small and enjoy high humidity, I highly recommend getting some kind of enclosure - a ten gallon aquarium can be had for $10 and is a great investment, plastic baggies work but are unsightly (I use these for propagation), clear food containers from the grocery store help some but usually don't provide a snug fit to the pot, 2 liter clear soda bottles can be a mini-humidity cover, plastic drinking cups for very small plants are cheap and very effective, etc. A self contained environment fills the bill nicely for hundreds of my humid loving plants and cuts down on watering chores significantly.

Talpa. Speak English!! Lol. I only really understood about half of that.

I do the pebble tray and we have a humidifier in the heating system but it all doesn't amount to much. The water in my aquariums evaporates so quickly that I'm constantly refilling them between changes.

I have one of those mist lamps that I think I'm going to set my Bulbophyllum right on top of. I always keep my fan on so I hope it works.

Then, when I finally clean them and get them working, I'm going to bring in two humidifiers I got for large rooms and set up my orchids near them.

I would also love to have one in the sunroom where most of my plants are kept but I doubt my parents will let me.

It's odd. They don't want them in the sunroom so I bought one of those plastic enclosed shelving units and I want to rig up some plain, compact, fluorescent lights for it and get most of my plants out of the sunroom but they're not for that either. I can't win. It would have helped a lot with humidity for some plants.

But that's kind of a different topic.

I also have those 40 gallon clear trash bags that I use but I can't do it for all the plants.

I use a humidifier and a few pebble trays, too, but personally I really feel that misting the top of the soil helps raise the humidity for an extended period of time.

I don't do it with every plant (that would take all day:) but just those that *really* need additional humidity.

Unless you mist every 5-10 minutes 24 hours a day it does nothing but maybe clean leaves off a little. A humidifier is the best way to provide humidity IMHO.

Our radio gardening guru, Ralph Snodsmith (the Garden Hotline), on the air right now, agrees with tommyr2006, 100%.

I'm listening right now as always Pirl!

Me, too! He's such a wonderful human being with such a good heart.

I'm going to jump in for misting. I know for a fact that my philos, pothos, anthuriums, begonias, and hoyas just love the misting when I get around to it. I also run the small hot air humidifiers during winter and keep definitely see the benefit. I even run a humidifier for the plants in the office that are growing via flourescents only.

Susan

i vote for misting too---