3 Best Grow Tent Humidifiers in 2022 (& What to Look For)

By: Chenell - Lead Writer and Gardening Advocate

A grow tent humidifier is an essential piece of equipment for any indoor garden. By regulating the humidity level in the grow tent, the humidifier helps to create a more hospitable environment for plants.

When choosing a grow tent humidifier, it is important to select a model that is specifically designed for use with grow tents, and is good for your grow tent size.

This will ensure that the humidifier is properly sized and equipped to maintain the desired level of humidity. With proper care and maintenance, a grow tent humidifier can provide years of service, helping to create a thriving indoor garden.

The Best Grow Tent Humidifiers

There are a ton of humidifiers on the market for grow tents – but here are the top ones I’ve found in terms of value and performance.

Levoit Humidifier

This top filling, Levoit cool mist humidifier is great for grow rooms and has a 360-degree mist nozzle to help you aim the humidity in a specific way.

LEVOIT 6L Humidifier
  • 6L water tank
  • Top Fill
  • Lasts Up to 60 Hours
  • 505 sq ft Coverage
  • Easy to Use and Clean
  • Filterless system
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The clear water tank is great to help you visibly see how much water is left. However with grow lights being on this a lot, it can grow some funky mold or algae in the corners.

The Levoit is a great grow room humidifier for up to 505 square feet of space, which would work well in most smaller grow tents as well.

Vornado Evap40 4-Gallon

This evaporative humidifier is a great option for larger spaces that need more air circulation as well. The Vornado Evap40 uses their signature “Vortex action” to circulate humidified air around your grow tent or grow room, where other humidifiers just pump the air out in the same direction.

Vornado Evap40 4-Gallon Evaporative Humidifier
  • 3 speeds
  • Adjustable Humidistat
  • 4 gallon water tank works on up to 1,000 square feet of growing space
  • Uses a signature Vortex action to circulate the humidified air
We earn a commission if you click this link and make a purchase at no additional cost to you.

The 4-gallon water tank is great for reducing the amount of times you’ll need to add water to the system. However, if you’re using it in a larger space, it’s going to use up more water than the average air humidifier (6 Liter) would.

Plus, the company offers a 5 year replacement warranty on this product, which is almost invaluable since other humidifiers might last just 1-3 years and then you’re out on the hunt for another.

The Evap40 also automatically tests the air and senses what the humidity level is at, and will adjust its output based on the current situation.

It also comes with 3 fan speeds for various humidity settings:

  1. Low – 750 RPM
  2. Medium – 1150 RPM
  3. High – 1600 RPM

This allows you to adjust the system to output the amount of humidity you want for your growing space.

Vivosun Cool Mist Humidifier

Vivosun is a brand that I love using. They have a great customer support team and try to take care of their customers as best they can.

VIVOSUN Cool Mist Ultrasonic Humidifier

This 6 Liter Ultrasonic humidifier is great for providing your plants with a cool mist to raise humidity in your grow tent.

  • Customized Humidity
  • Remote Control
  • Auto Shut Off
  • 360° Nozzle

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This is actually a hybrid option of humidifier, as it’s both an Ultrasonic humidifier but also a cold mist humidifier. That means you get the quietness of the ultrasonic, but the cool air as well.

This humidifier is best for grow rooms or grow tents up to 250 square feet, which will work great for a 2×4 or 3×3 grow tent.

You also get a top nozzle that is able to be rotated 360 degrees, perfect to make sure the humidity and vapor is headed in the right direction.

The Vivosun also comes with a cleaning brush that is included in the base of the humidifier. Since humidifiers can get dirty pretty regularly, this is a huge help when going to clean it.

Pros and Cons of Using a Humidifier

There are pros and cons to using a humidifier, so let’s walk through them to help you make the best decision.

Advantages of a Humidifier

A humidifier can increase the humidity of your grow tent or grow room FAST. We’re talking much faster than some other methods. The humidifier mist quickly reaches the tent and will begin to raise the relative humidity.

Additionally, the humidifier can help to prevent slow plant growth, as well as a whole host of other issues.

The Downsides

The cost is probably the main downside. Of course, a humidifier is going to cost more than a bowl of water sitting in the bottom of a tent. However, it’s much more effective, especially as your grow space size increases, or if you live in a really dry environment.

The other downside is maintenance, cleaning and upkeep. Anything that processes water has the potential for mold, mildew, and other sludge to grow inside. You’ll need to stay on top of cleaning so the air getting pumped out isn’t passing through that sludge and reaching your plants.

What to Look for When Buying a Grow Tent Humidifier

There are a number of things you want to look for when considering a humidifier. After all, some of them are not cheap, so you want to make sure it’s going to provide the right humidity levels and work for your size grow tent.

3 Types of Humidifiers

There are a few different types of humidifiers you can choose from.

1. Cool Mist and Warm Mist Humidifiers

A warm mist humidifier are better for cold climates, as they heat the water in order to create a vapor. They can be harder to clean but do cut down on the growth of microorganisms.

A cool mist humidifier

I lumped these together because there are some models that create both warm or cool mist from the same machine. Having both allows you to either raise or lower the humidity levels in your tent slightly.


  • A cool mist humidifier cool down the tent there are higher temperatures


  • Warm mist humidifiers are not as effective in larger grow rooms

2. Evaporative Humidifiers

Evaporative humidifiers use a wicking action to move the water from the holding tank into the air. The wicking filter clears the bad stuff/impurities from the water and is then blown out of the system by a fan that helps evaporate it into the air. These are also sometimes called steam humidifiers.


  • The filter will reduce the risk of fine white dust being exposed into the room
  • Faster at getting humidity levels up


  • Tend to be louder than other types
  • Some substances that were in the water will make it into the air

3. Ultrasonic Humidifiers

An ultrasonic humidifier uses a high frequency sound vibration to push a fine mist into the environment. These tiny droplets evaporate shortly after being emitted from the humidifier.

There is no heating element to the ultrasonic humidifier and it uses ceramic plates to do all of the work. Because of this, these are considered a cool mist humidifier as well.


  • Quietest option of the 3 types


  • Potential white powder can coat the plants because of what was in the water initially

Humidifier for Different Sized Tents

When choosing a grow tent humidifier, it is important to select a unit that is appropriately sized for the space. Too small of a unit will not be able to raise the humidity level enough, while too large of a unit may make the grow tent too moist, which can lead to mold or mildew growth.

Humidifier for 2×4 or 4×4 Grow Tent

Most budget humidifier will work well for smaller grow tents. This one would be my pick for both the 2×4 and 4×4 grow tent, as they are generally less than 250 square feet.

For other tent sizes, you’ll want to pay attention to the square footage of the tent and the square footage the humidifier claims to work with.

grow tent humidity

Capacity of the Water Tank

The water capacity of the humidifier is going to be important depending on the size of your grow tent, and how frequently you are able to tend to you grow space.

Most smaller, budget humidifiers come with a 6 Liter water tank, which is great for most home grow spaces, but if you are in a large area, or might be out of town for a few days at a time, you may want to get one with a more robust water tank.

This humidifier has a 4 gallon tank which would work well if you don’t want to constantly be refilling the tank.

Humidifier Noise Levels

Let’s be honest, a lot of home grow room setups are in a bedroom or office, where you don’t want a loud fan running constantly. Paying attention to how loud or quiet a specific humidifier is will help you avoid frustrations down the road.

Some models have a “whisper quiet operation” that claims to be almost silent, but you want to check reviews and see if that’s actually true.


Humidifiers that come with filters are something to keep in mind as well. Filters need to be cleaned, and can clog up the operation of an electric humidifier pretty quickly.

The Ultrasonic humidifiers typically don’t have filters, but because of this, they might need to be cleaned more frequently. Which leads us into the next section.

Cleaning & Maintenance

The best humidifier would be one that didn’t need to be cleaned that often, and doesn’t get clogged up or weird pink stuff in the corners of it.

But life isn’t perfect. So you want to be aware of what you’re getting yourself into before purchasing.

How Does a Humidifier Work & Do You Need One?

Let’s start with how a humidifier works so you can understand why some of these options are important.

A grow tent humidifier is a small, self-contained unit that is designed to raise the humidity level within a grow tent. By adding moisture to the air, a humidifier can create an ideal environment for plants inside your grow tent.

If your grow tent doesn’t have enough humidity for the plant, you will see decreased yields and slower plant growth, along with problems like brown leaves or wilting plants.

Where to Put a Humidifier in a Grow Tent

The placement of your humidifier in the grow tent isn’t super critical, but you do need to make sure the air spout or nozzle is pointed towards your plants or at least towards the ceiling.

Should a Humidifier be Inside or Outside the Grow Tent?

A typical humidifier will need to be inside of the grow tent. By typical, I mean a smaller unit you can buy online for less than $100.

If you are building a larger DIY humidifier with proper ducting running into the tent, then the base of it can do just fine right outside the tent.

Do You Run the Humidifier 24/7?

You can leave the humidifier plugged in all day, but I would make sure it’s hooked up to a controller. This will automatically turn off the humidifier when the desired humidity is reached so you don’t end up with too much moisture inside your tent.

The Best Grow Tent Humidifiers

Finding the best humidifier for your situation can be a challenge, but I hope this post was helpful for finding the right one to help mediate the dry air in your tent.



Hi - I'm Chenell! I lived in the city for almost a decade, but after moving to the suburbs in 2020, I decided the logical millennial thing to do was to learn how to grow my own avocado toast. That's what this site is all about. 🥑

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