Indoor plants offer an aesthetic appeal, plus they remove allergens from the air and oxygenate the space. The key to keeping your indoor plants thriving all year round is maintaining humidity levels that are specific to the plant types. And often, simply watering your plants isn’t enough to keep moisture levels optimal. Humidifiers can add moisture to air and are especially beneficial during the colder months because cooler air tends to be a little dryer. In addition, indoor air loses moisture from heating (central heat or fireplaces), which can leave your plants looking a little wilty and dull.
Increased moisture in the air can help you as well by fending off dry sinuses, dry skin, and sore throats. A humidifier can keep your indoor plants happy and healthy. When it comes to choosing the best humidifier for your plants, read through this list of top humidifiers and features to consider on your purchasing journey.
- BEST OVERALL: LEVOIT Cool Mist Humidifiers
- BEST COMPACT: Pure Enrichment MistAire Ultrasonic Cool Mist
- BEST LARGE CAPACITY: LEVOIT 6L Warm and Cool Mist Ultrasonic Air Vaporizer
- BEST EVAPORATIVE: Vornado Evap40 4-Gallon Evaporative Humidifier
Types of Humidifier for Plants
Humidifiers work by discharging moisture into the air. While you might be familiar with a basic humidifier, you might be wondering how it differs from a humidifier indicated for plants. Although the function of a humidifier is consistent between models, it’s the amount of moisture discharged that can make the difference—and just like plants, humans can benefit from eliminating low humidity during dry seasons. The two main types of discharge techniques are described below.
Ultrasonic humidifiers use high-frequency (ultrasonic) vibration to facilitate the water’s evaporation. The vibrations steam the water, producing extra-fine droplets. Ultrasonic humidifiers typically cost a little more than evaporative ones, have no filters to change, and are quieter. Because the ultrasonic conversion of water to mist doesn’t require heating the water, there’s less risk of burn injuries from spills. The drawback is that the absence of heat that would normally inhibit bacteria and mold growth requires you to disinfect the unit regularly to prevent contamination.
Evaporative humidifiers use airflow to create mist by using a fan to pull water over a wet wick. Evaporative humidifiers also contain filters, which need periodic changing to prevent the growth of mold and bacteria. Although these types of humidifiers are less expensive than ones with ultrasonic technology, they can run a little noisy because of the fan that pushes air movement to generate moisture.
What to Consider When Choosing the Best Humidifier for Plants
Understanding a little about humidity can help you determine which humidifier is best for keeping your indoor plants thriving. Humidity is the amount of water (water vapor) that is suspended in the air at any given time. Cooler temperatures tend to remove moisture from the air, and a humidifier is a convenient and inexpensive way to maintain humidity levels that are ideal for indoor houseplants and to help humans avoid dry sinuses and skin during the colder months.
It’s important to find a humidifier with a moisture output that matches your room’s size. If your humidifier’s output is less than what the size of your room requires, you might not achieve optimal moisture dispersion. It’s also helpful to consider where you’ll locate your humidifier. It’s best to place your humidifier at least 6 feet away from your plants, especially if your unit has a fan because the direct airflow can contribute to your plants’ moisture loss.
The size of a humidifier’s water tank is directly proportional to the amount of time a humidifier can run. The larger the tank, the longer you can expect to run the unit without needing to refill it or shut it off. If you require less moisture, you can find small and attractive units that are great for small spaces with limited moisture requirements.
When it comes to the humidity your plants prefer, mist temperature isn’t as critical as you might think. Warm mist tends to be purer because it’s generated by evaporation, but cold mist is a little more cost-effective to generate because cool-mist humidifiers require less energy to run.
Humidity Output and Settings
The amount of moisture released by your humidifier should match the temperature of the room—to avoid releasing too much or not enough moisture. For that reason, humidifiers are designed with mist output controls to make adjustments according to the ambient air environment. Most humidifiers come with at least two settings: low and high. However, three-speed units are available if you think you’ll need a little more control over the mist output. Some models also record relative humidity percentage to help you gauge the ambient humidity levels of your space or room.
To keep your humidifier running at full efficiency, it’s best to replace its filter every two to three months—maybe more frequently if you use tap water. Follow the manufacturer’s instructions for your humidifier’s scheduled maintenance recommendations. There also are filterless units available if you prefer a low-maintenance option.
When it comes to noise levels, all humidifiers are not equal. If you spend time in or near your grow space, you might want to consider a unit with low noise output. Evaporative humidifiers tend to generate more noise than ultrasonic models from the fan that’s used to pull air across the wicking component.
Setup and Maintenance
Periodic maintenance of your humidifier can help keep it running efficiently and keep it free from bacteria and mold that can grow in the tank without proper cleaning. If left unchecked, mold can be released in the mist, causing allergies and respiratory illnesses. Along with cleaning the tank, cleaning or replacing the filter will help ensure the humidifier’s mist isn’t contaminated with allergens. Cleaning your tank once a week with bleach will help prevent unwanted mold and mineral buildup.
Our Top Picks
This list recommends some of the best humidifiers, by category, for keeping your indoor plants’ moisture requirement optimal for year-round growth and survival.
LEVOIT’s ultrasonic air vaporizer is an excellent option for plant lovers on a budget. For the price, the unit comes with several standout features that make it more than just an economical choice. The unit has a 2.4-liter water tank, an optional night-light, and a patented silencer. The LEVOIT comes with low, medium, and high settings, and it can run for up to 24 hours continuously on the low setting. The 360-degree rotating nozzle ensures the mist disperses evenly in up to 290 square feet of space, and the unit will shut off automatically when it detects that the water level is low.
- Portable unit
- Night-light feature
- Runs very quietly
- Difficult to clean inside parts
The Pure Enrichment humidifier’s 1.5-liter water reservoir and sleek base make it a great choice for small spaces like offices, plant rooms, and lanais up to 250 square feet in size. With low and high settings and a 360-degree mist nozzle, it lets you choose the ideal moisture dispersion for your space. The unit can run for 16 hours continuously for overnight or all-day operation. It also features a night-light function and automatic shutoff that turns the humidifier off when the water tank level is low.
- Great for small spaces
- Cleaning brush included
- Excellent customer service
- Small water tank
- Bright power light can be disturbing
The settings, sensors, and large water tank of this LEVOIT model give you customized control over your space’s humidity levels, adjusting the humidity according to preset levels. The unit comes with a remote, which allows you to adjust the settings without leaving your bed or desk. Other notable features include both warm- and cool-mist dispersion, an aromatherapy feature for essential oil use, and ultra-quiet operation. The unit can provide humidity for spaces up to 753 square feet and can run on one tank of water for 60 hours continuously—but if you prefer following a schedule, you can set the timer for one to 12 hours for just the right duration for your plants.
- Comes with a remote
- Warm and cool mist options
- Various settings to choose from
- One tank last for several days
- Refilling the tank can cause leaks
Vornado’s evaporative humidifier uses vortex action to humidify spaces up to 1,000 square feet, and the 4-liter water tank can sustain moisture output for up to 24 hours. The control panel allows you to adjust both fan speed and humidity output. The humidification feature senses the amount of circulation and humidity necessary to maintain moisture in the environment based on the control settings and makes adjustments to the moisture output accordingly. Two easy-refill tanks make refilling the humidifier easy and mess-free.
- Great for large areas
- Tanks are easy to fill
- Automatically controls humidity
For small areas that need to stay humid, the LEVOIT Cool Mist Humidifier is a solid choice at a competitive price. Shoppers looking to control the humidity in a larger area should consider the Vornado Evap40 4-Gallon Evaporative Humidifier, which can maintain the set level automatically.
How We Chose the Best Humidifiers for Plants
This list of recommendations covers the range of options available to shoppers, from small portable units to help keep a few plants hydrated (and that are easy to move around to several places in the home), to large units suitable for a whole room full of exotic flora.
We have made sure to consider the most important aspects of humidifiers when curating our top picks, namely noise level, filter life, and tank capacity. As such, our suggestions all run smoothly and quietly to avoid disturbing users, and we feature a range of tank sizes to suit the variety of uses a shopper may be looking for. In terms of filter life, our research led us toward trusted brands known for their product longevity, ensuring a humidifier capable of keeping your indoor plants healthy for years to come.
When using a humidifier to optimize your home’s humidity level for keeping your indoor plants thriving in every season, here are a few answers to some common questions about humidifier use to get you on your way.
Q. What kind of humidifier is best for plants?
The best humidifier depends on several factors, including the size of the room, typical ambient conditions, and the amount and duration of humidity required by your plants.
Q. Do humidifiers cause mold?
When not properly maintained and cleaned, a humidifier can grow mold in the water tank and on the filter. The mold can then be dispersed into the environment with mist, triggering a variety of respiratory issues, from allergies to asthma.
Q. Is warm mist or cool mist better for plants?
You can use both warm- and cool-mist humidifiers with indoor plants. The biggest difference between the two is that cool-mist humidifiers use a filter system, which is more energy-friendly than the evaporation method of warm-mist humidifiers.
Q. What is the best humidifier placement for plants?
Keeping your humidifier about 6 feet from your plants will ensure they receive adequate moisture. However, it’s advised to not keep them any closer than that distance to avoid accumulation of excess moisture on the plants’ leaves, which could give way to fungus and mold growth.
Q. How often should I use a humidifier for my plants?
When it comes to the frequency at which you should be running your humidifier, follow your plants’ cue. Wilty leaves with brown tips can indicate that your plants are not receiving enough moisture. Stunted growth and blossoms prematurely dropping also can indicate low humidity.
Q. How long should I run my humidifier for plants?
How often you need to run your humidifier depends largely on the types of plants you have and the season. Tropical plants require a longer duration to supply sufficient moisture, while succulents require less.
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Alisa Martin is a freelance writer, specializing in the do-it-yourself, fitness, travel, and education industries. Following a career as a Molecular Technologist, Ms. Martin spent a season as an ISSA personal trainer before moving to North Africa where she served as an English lecturer for a British university. Growing up in a gardening, woodworking family and living abroad have given her a passion for all things repurposed, restored, and sustained. She loves to join conversations centered around budget-friendly, energy-conserving projects that involve the entire family and promote community. When she’s not writing or managing her family’s roofing company, she’s either jogging, exploring international destinations, or enjoying the Gulf Coast’s beautiful beaches with her kids.