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There is plenty of evidence to suggest that misting house plants with a spray bottle can actually cause problems for both them and you. Misting DOES NOT increase humidity. It just…doesn’t.
There isn’t a group of plants that like to be misted and others that don’t. Misting has no benefit to house plants, and can be detrimental to their health.
If you have undisputable PROOF that misting helps plants, then I’m all ears. Leave me a comment and CHANGE MY MIND. ***Brief interlude where I research how to make a meme, then make a meme***
I mean, it’s probably been done, but it was cathartic if nothing else.
Why do people recommend misting plants?
People recommend that we mist our plants because many of the house plants that are popular come from tropical rainforests, where it’s VERY humid.
However, misting does not increase the humidity of a room for more than a minute or two.
And you know what plants like? Consistency in their environment.
And whilst misting does increase humidity momentarily, as soon as the water settles (a couple of minutes) the humidity is pretty much back where it started. Your plant is the same as it was before, only wetter.
Diffusion (the movement of particles from a high concentration to a lower one) of water particles will begin immediately. The particles will spread out, but they won’t increase. Humidity won’t be altered by more than a tiny fraction.
By the way, plants DO NOT enjoy having wet leaves. They just have to deal with it because their roots need it.
Humans also need water. We will die without it in literally days. Do we like to get wet? NO. It inhibits our basic functions. Plants are the same in that respect.
Misting is worse that not misting.
If you don’t have a humidifier, don’t think that you can replace that with a few spritzes of water. Instead, steer towards plants that suit your home better – Agaloanema instead of Calathea, rubber plants instead of peace lilies, and don’t, under any circumstances, consider a fittonia unless you get a terrarium.
How can misting benefit your house plants?
There are good reasons for misting your plants, but it’s not to do with humidity.
Misting your plants does have the beneficial side effect of knocking off some dust and maybe even the odd bug, BUT I highly recommend following up your misting session with a cursory wipe-down of the leaves.
Having wet leaves can also make an inhospitable environment for pests that love dry conditions, such as spider mites. The flip side of this is that a damp environment is a haven for other pests, such as fungus gnats, as well as bacteria and funguses.
Does misting actually raise the humidity in the room?
No, misting has a negligible effect on the humidity of a room. As I mentioned before, the water particles begin diffuse the second they’re released from the mister. A high concentration of water vapour around the plant will disperse around the room in a few seconds.
If you stood and sprayed consistently with a very fine sprayer, then you could successfully increase the humidity of the room, but it’d be a 24/7 job.
Misting can work in a very small enclosure. We successfully kept our small terrarium at 90% humidity by spraying it down twice a day, but since we upgraded to a larger terrarium, we invested in an automatic mister. A mister is a humidifier, but it’s a bit more powerful, and creates a cool misty effect.
Is humidity that important when it comes to the health of your plant?
In order to successfully keep house plants, we need to replicate their natural environment as closely as possible.
As I said at the start, a lot of house plants hail from the tropics, where it’s warm and humid.
High humidity helps to facilitate the exchange of gases required for the plant to photosynthesise effectively.
If the atmosphere isn’t humid enough, water will be pulled from the stomata by the dry air. In response, the plant will close its stomata. If the stomata are closed, photosynthesis can’t occur, and the plant can’t grow.
Before running out and buying a humidifier, I highly recommend that you first purchase a hygrometer (or borrow one from a friend) – they’re pretty cheap.
Put it where you want your plant to live, and leave it for 24 hours. If it reaches 65% that’s probably enough to keep most plants happy.
Then you can decide on a plant that’s suited to your home’s natural environment. Just be aware that humidity tends to decrease in winter, so you may get some crispy tips.
If you can’t be bothered with the hassle, pick plants that don’t require more than ambient humidity, which is USUALLY 40% or less. Mine’s 60%, but if you live somewhere that’s hot and dry, it could be less.
Ten plants that require 40 % humidity or less
- Cacti – excluding Christmas cacti and his easter and Thanksgiving mates
- Hoya – though it varies from plant to plant. Prefer 50% but will tolerate 40%
- Pothos – just generally hard to kill
- Sansevieria – see pothos
- ZZ plant – again, hard to kill
- Monstera – it would prefer higher, but won’t complain at 40%
- Ficus Robusta (Rubber plants
- Asparagus fern
- Ponytail palm
Stay away from Calathea, ferns, Stromanthe, Ctentanthe, and African violets. Philodendron generally prefer humidity levels of 50%+ but there are a few that would probably tolerate lower humidity – heartleaf are generally pretty chill, as is my Golden Dragon.
Can misting my plants damage them?
Misting mimics rain. It’s one of the reasons that misting advocates continue to spray away.
Rain can be dangerous to plants, which sounds ridiculous because it’s obviously natural, but the fact is that only roots need water. The rest of the plant would prefer to stay dry.
If a plant detects that it has water sitting on the leaves, the stomata will close. Stomata don’t necessarily close when it’s raining, but they will if there’s prolonged moisture.
When the stomata are closed, then the plant can’t photosynthesise. No worries, it’ll get on with other plant stuff it has to get done. The stomata can then take a while to reopen, so a few seconds of misting can cause the loss of a few hours of photosynthesis.
Plants have evolved so rain runs off them
A lot of plants have drip tips – the ends of the leaves taper to a point that rain can run off them.
Wet leaves can cause hitchhikers
This is less of an issue in our homes, but wet leaves in the wild can lead to unwanted guests. Moss, lichen, and even small plants can grow on damp leaves. Not only will this block the stomata, but it’ll block out the sun.
Misting can transfer pests
This is unlikely, but if you have low humidity you may have grouped your plants together to help increase it a bit. Pests transfer between plants pretty easily anyway, but you don’t want to facilitate it even further by literally blasting them between plants.
Misting can cause mould
Grey mould is a disease caused by the fungus Botrytis cinerea. It’s not the same as mould on the soil, which is pretty common and not harmful. Grey mould can kill plants, and usually occurs when the leaves stay wet for prolonged periods of time.
Misting can cause damp soil
Great, right? NO. Damp soil on the top layer creates a breeding ground for fungus gnats. Fungus gnats aren’t particularly dangerous, but they’re extremely annoying.
What should I use to mist my plants?
If you enjoy misting your plants but don’t want to harm them, you don’t need to stop completely.
First, make sure that they have the humidity they need (and understand that misting will not help with humidity).
Then make up a spray bottle filled with warm water and a drop of neem oil. Mist your plant thoroughly with this mixture every couple of weeks but make sure to dry them off afterwards. This should help to keep pests at bay and keep the leaves dust free.
Another option is to buy (or make) a foliar spray. This is a great way to add a bit of nutrition to plants that’s a bit more fun than traditional water-in fertilisers.
Do I mist my plants?
No. But I know a lot of people that SWEAR it benefits their plants, so if you want to go ahead.
I do have a tiny theory on why misters see results – I think it’s for a similar reason that some people swear their plants grow more if they’re spoken to. If you’re misting your plants, you’re paying attention to them, so you’re more likely to notice if they’re thirsty, need repotting, or have pests.
What about misting moss poles?
Misters, listen up! If you love to mist everyday, then consider getting a moss pole to mist.
Moss poles need to be damp if you want the aerial roots to grow into them. Keeping moss poles damp is a full-time job, so I don’t tend to bother (I just zip-tie the plant to the pole).
If you use coir poles, like this one:
…You can mist it if you like, but you’re looking at doing it AT LEAST daily if you want it to stay damp. I don’t really recommend these if you’re looking to mature your plant and grow its aerial roots but they’re fine if you just want your plant to be a bit tidier.
These sphagnum-filled poles are better:
Don’t get too excited about the aerial root stuck in the pole – I did that myself. These poles stay prey damp if you keep them well misted – they’re great if you just like misting.
(I personally don’t have the time or inclination to mist my moss pole daily, so I dampen mine with a homemade water gun made by drilling three holes in the top of a water bottle and *gently* blasting the moss pole with that every couple of weeks.
The most positive likely outcome of misting house plants is that nothing happens.
It’s highly unlikely that your plant will receive any benefits from being misted, and it’s certainly not a replacement for a decent humidifier.
Good humidity has a massive impact on the health and speed of growth of tropical houseplants.