If you’ve ever walked into a botanical garden or been fortunate enough to travel to a tropical area, you’ve been blasted by warm, humid air. When I first got into houseplants and tropical plants, I was shocked at how much humidity some of them needed to thrive.
Taking care of my new plants seemed simple enough: just give them more humidity, right? Unfortunately, I live in an area that gets a lot of sun but doesn’t naturally have higher humidity (Zone 10b). I also grow plants that hate higher humidity as well, so I didn’t want to just increase the humidity in my garden overall.
So, what could I do for my precious plants that love bathing in humid air?
First, I tried out humidity trays, which are just trays half-filled with water and pebbles. I placed my plants on top of them and hoped for the best. It worked — a little. After a while, even this method failed me and I decided to purchase a humidifier to solve my problem.
The problem is, most humidifiers are made for people, not plants. I had to dig deep into the qualities of humidifiers to figure out which ones were the best fit for my green babies. Below is my advice for selecting the best plant humidifier, as well as some of my recommendations. I’ve listed my recommendations quickly at the top, but I also go into them in more detail below.
My recommended plant humidifiers:
|Best OverallHoneywell Germ Free Cool Mist HumidifierBest Overall||Check Amazon Price|
|Adjustable NozzleEverlasting Comfort Ultrasonic Cool Mist HumidifierAdjustable Nozzle||Check Amazon Price|
|Warm MistVicks Warm Mist HumidifierWarm Mist||Check Amazon Price|
|Long RuntimePure Guardian Cool Mist HumidiferLong Runtime||Check Amazon Price|
|Night LightPure Enrichment MistAire XLNight Light||Check Amazon Price|
|Smart HumidifierLEVOIT 6L Ultrasonic Top-Fill HumidifierSmart Humidifier||Check Amazon Price|
|Multiple SizesGENIANI Cool Mist HumidifierMultiple Sizes||Check Amazon Price|
The Best Plant Humidifiers
- CLEANER INVISIBLE MOISTURE – Honeywell Cool...
- EVERYDAY COMFORT – This humidifier for home...
- EASY TO USE – Featuring a large 1.1 gallon,...
The Honeywell model is my top pick for the best plant humidifier you can buy. It’s an evaporative type that includes ultraviolet technology to disinfect and sterilize the water as it passes through the system. This is great for our purposes, because the last thing we want is to disperse pathogens through the air in vapor.
It has a 24-hour run time, which is twice as long as my budget humidifier pick. It comes apart easily for cleaning and maintenance and also includes a filter to remove minerals and salts from the water before evaporation.
For all its benefits, the filter is also the only downside as it needs to be replaced every so often. It’s also bigger than most humidifiers, but not by much so it’s not a huge deal.
It comes in either white or black and is only around ~$15 more expensive than my value pick. To me, that makes the Honeywell Cool Mist Humidifier a no-brainer purchase.
- 50 Hours Without a Refill: The large capacity 6L...
- Higher Multidirectional Mist Output: Fully...
- Whisper Quiet: Our large room humidifier is nearly...
The Everlasting Comfort cool mist humidifier is adaptable to both human and plant needs. However, I wouldn’t use it for essential oils if you’re also using it for plants as they are sensitive to concentrated substances.
But this large humidifier will moisten the air for plants in a 500 square foot room with a 6 liter tank capacity! Another really awesome feature this humidifier has is a 360° adjustable nozzle which adds aiming functionality to the mix.
It’s whisper quiet, and relatively affordable for such a large coverage area. There’s also an accompanying 2 year replacement policy, giving you a lot of time to figure out if the Everlasting Comfort is for you.
- POWERFUL PERFORMANCE, FUllY UPGRADED: The...
- BEST HUMIDIFIER FOR BEDROOM: Lying in bed, using...
- BETTER SMART CARE: Simply use the free VeSync APP...
Here’s another large capacity humidifier from LEVOIT, a company that specializes in humidifiers for plants and people. This one costs just as much as the Everlasting Comfort with the addition of smart tech, which allows you to control every aspect — minus cleaning — with your smart phone!
With the LEVOIT Ultrasonic Cool Mist humidifier, you can access the app anywhere and control it with the touch of your smart phone screen. Its large tank capacity and design makes it easy to clean, and LEVOIT customer service is tip top!
Just remember to uninstall the included aroma pad before humidifying a room full of plants, and don’t couple the the mist of essential oils with plant care. Along with the aroma pads, though, you’ll have additional water filters and a cleaning brush included.
- ✅ BECAUSE YOU DESERVE THE BEST: Our classic,...
- ✅ INNOVATIVE AUTO-FUNCTION FOR YOUR CONVENIENCE:...
- ✅ NEXT-LEVEL APPROACH FOR DAILY USE: Sick of...
The Geniani top fill humidifier for your plants has a tank capacity designed for large rooms, and it’s easy to refill. As a cool vapor humidifier, has a smart sensor that turns itself off when the proper humidity is reached. It has a sleep mode option which might be useful with your indoor space.
It has tons of functionality with 4 different settings, and it won’t make a sound while you use it. If you want the same performance as the LEVOIT humidifier with slightly less accessibility, this is the humidifier for your plants.
Not only does it have multiple settings, but it also has the option of portability with multiple size options.
- WARM MIST HUMIDIFIER – Vicks Warm...
- COUGH AND CONGESTION RELIEF – Vaporizers for...
- QUICK AND EASY TO USE – This filter-free...
The warmed mist produced by this Vicks humidifier is comfortable for both you and your moisture-loving plants. It’s not a hot mist, but warm enough that your tropical plants will be happy, and so will you!
With a one-gallon water tank, it’s capable of running up to 24 hours. Once it runs out of water, it’ll automatically shut off, so you don’t have to worry about damaging the device by running it dry.
It’s simple, bare-bones, but very functional, and deserves a slot on our list!
- COOL MIST HUMIDIFIER: The PureGuardian H965...
- SILVER CLEAN PROTECTED TANK: Silver Clean fights...
- AROMATHERAPY TRAY: The aromatherapy tray option...
Another cooling mist option, this is slightly less variable than the other devices. There aren’t any variations in mist size, but it does have a sizeable water tank and auto-shutoff so it won’t run while empty.
The mist is multidirectional, so it goes in multiple directions around the plant humidifier. This is great if you’re looking for one device to handle an entire room full of plants, but not so great if you have it up against a wall!
Overall, though, this is a solid device and something to keep in consideration.
- LONG-LASTING RELIEF: Ultrasonic cool mist...
- 1 GALLON WATER TANK: Large tank and powerful steam...
- OPTIONAL NIGHT LIGHT: Offers soothing lighting for...
One of the biggest perks of this model is that it has an extended warranty over most of its competition. Five years is a long warranty time for a device like this! The MistAire XL also has different mist sizes, a 1-gallon water tank capacity that holds plenty of water, and automatic shut-off.
But even better: it can be a light if you’d like it to be. A soothing blue or green light, or a warming red light, will remain illuminated to give you just enough light to see by.
What Is Humidity?
It’s important to understand what humidity is and why certain plants need higher or lower humidity levels. By understanding this, we’re able to customize our plant’s environments so they truly thrive.
At its simplest, humidity is a measure of the amount of water vapor present in the air.
There are two common definitions of humidity:
Relative humidity – How much water vapor the air is currently holding relative to how much it can hold at a certain temperature.
Absolute humidity – How much water is in a cubic meter of air.
The higher the temperature of air in a given space, the more water vapor it’s able to hold. This is why plants that require higher humidity usually require higher temperatures as well — the two go hand-in-hand. Here are a few different growing environments for reference:
- Desert – Hot air, low humidity due to low water availability
- Arctic – Cool air, high water availability but still low humidity
When I said that warm air “holds” more water, that wasn’t quite accurate. Warmer air simply causes water to evaporate faster, resulting in more water vapor in the air.
Why Do Some Plants Need Higher Humidity?
Plants evolved to adapt to their native environments. In areas where high humidity is the norm, many plants responded by reducing the amount of water that their leaves can hold. Just like how succulents adapted to hold a lot of water in their leaves, plants native to high humidity areas adapted to do the exact opposite. Some plants also don’t have robust root systems, so they can’t draw much water from the ground.
Furthermore, epiphytes are plants that absorb all of the water they need from the surrounding environment, meaning that they require high relative humidity to survive.
Common Humidity Levels For Houseplants
All plants are different and will require different humidity levels. However, here are some general guidelines for common houseplants:
- Orchids – 40-70%
- Ferns – 40-50%
- Most other houseplants: 40-60%
Types of Plant Humidifiers
Humidifiers for plants work in three basic ways: warmed mist, ultrasonic, and evaporative.
Warm Mist Humidifiers: These are the most common type of humidifiers for plants on the market. The way they work is simple: they heat water up to a high temperature, causing it to become vapor. It’s then sent out into the environment to boost the humidity of the surrounding area.
Ultrasonic Humidifiers: These are a unique type of plant humidifier that use vibration to increase the evaporation rate of the water in the water tank. You’ll be able to tell it’s an ultrasonic humidifier by the quality of the mist — it’s quite fine and wispy. Here you’ll find both warm and ultrasonic cool mist humidifier options.
Evaporative Humidifiers: These use airflow to create vapor. You may know of swamp coolers, which work similarly. Evaporative coolers draw water from their water tank over a wicking material (like cloth or felt).
Next, a fan forces air over the wet wicking material, which adds vapor to the air. It then flows out into your garden, giving your plants the humidity they so desperately want. Voila! Evaporative humidifiers.
Warm vs. Cold Mist
You might be wondering whether it matters if your plant humidifier puts out a warm or if you’re working with cool mist humidifiers. The answer is: no! It doesn’t really matter at all. The increase or decrease in temperature that results from warm or colder mist will be barely noticeable.
One potential benefit to warm-mist humidifiers is that they create mist via evaporation, so the vapor will be purified. However, they tend to use a bit more electricity as they need to heat up the water.
Cold-misting humidifiers tend to use less energy and can be run for longer periods of time, making them lower-maintenance choices overall.
Features That Make a Humidifier Good For Plants
Humidifiers are made for humans and not plants, so there are a few features that aren’t perfectly calibrated for our indoor plants. That said, here’s what you should look for when it comes to picking the right humidifier for plants:
- Run Time – At least 12 hours of run time and ideally over 24 hours. You don’t want to have to refill it constantly.
- Simple Design – You’ll be using your humidifier more than most, so it must be easy to maintain and take apart.
- Small and Attractive – These aren’t necessary features, but I personally like looking at well-designed and compact humidifiers!
These rules go out the window if you are trying to increase the humidity in a larger space like a greenhouse. You should probably go with misters or foggers to humidify a space of that scale.
How to Best Use Your Humidifier
It’s not enough to plop a humidifier in your garden, turn it on, and expect your plants to thrive. You have to build an environment that is conducive to higher humidity as well.
Proper airflow is a must, especially because many diseases thrive in higher humidity. If you let water condense and sit on your plants, you’re asking for leaf spot fungus and all sorts of other diseases.
Here’s a good basic setup for high-humidity environments and humidity loving plants:
- A high-quality humidifier for plants (reviewed below)
- A fan to increase air circulation
- A tray filled with water and pebbles to catch extra moisture
- A temperature and humidity monitor to keep track of levels
Maintaining Your Humidifier
A good rule of thumb is to completely clean your humidifier a few times a month. Because you’ll be using it often, you’ll have a salt, fungus, or mold buildup quicker than other users.
To clean, simply deconstruct the humidifier and soak the parts in a mixture of water and vinegar.
Frequently Asked Questions
Q: Are plant humidifiers worth it?
A: Absolutely! As you can see from the intro of this piece, other methods are viable for a time, but may not hold up over time. Plant humidifiers have much more to offer in longevity and functionality.
Q: Which humidifier is best for plants?
A: Based on this list here, we’ve chosen the Honeywell Germ Free Cool Mist Humidifier as the Best Plant Humidifier Overall. Check that section to see why we’ve put it at the top of our list.
Q: How do you naturally humidify a plant?
A: In lieu of a plant humidifier, you can use a pebble tray, or mist your plants daily with distilled or filtered water.
Q: How big of a humidifier do I need for plants?
A: The size of your humidifier depends on the size of the room where your plants live. As a general rule, 300 square foot rooms do fine with a small humidifier. For 400 to 500 square feet, medium sizes work, and large ones are best for those room larger than 500 square feet.
Q: Will a plant humidifier cause mold?
A: It’s a possibility for humidifiers, but many are designed for prevention of mold and bacteria buildup. However, we do recommend that you clean your humidifier a few times per month to once per week.
Q: Should I leave my plant humidifier on all night?
A: It’s better to run it for a few hours in the morning into the early afternoon. While plants like humidity, too much creates conditions where diseases proliferate. Give the room humidity it needs early on, and allow the dryness to set in overnight.
Q: Can I use tap water in humidifier for plants?
A: You can! Humidifiers are designed to handle the minerals present in tap water. While these minerals can build up over time, as long as you properly clean your humidifier, you shouldn’t have issues with buildup.
Q: Do plants need warm or cool mist humidifier?
A: To a plant, there’s no difference in the mist temperature. However, warm misting humidifiers sanitize the water as they heat it to vapor. That means there’s a slightly smaller chance that humidity-borne diseases can develop with a warm mist temperature.