Hydroponic ventilation systems are the perfect way to up your game if you’re looking to improve your grow setup. Think about it- plants are exposed to breeze all the time in nature. It only makes sense that there would be advantages to mimicking the breeze! Ranging from humidity control to stronger stems to decreased pathogens, hydroponic ventilation will be your new best friend in no time.

Read on to learn about the impressive benefits that a little bit of air can bring!

How important is ventilation for hydroponics?

Ventilation is very important for hydroponics. 

The reason hydroponic growing is so successful is because you’re able to control every single factor in order to create the most optimal growing environment possible.

Outdoor plants benefit from the gentle breeze in many ways, which we will dive into in this article. 

For indoor growers, proper ventilation is the solution in order to reap those benefits and best replicate the natural environment for healthy plant growth.

While ventilation is an often-overlooked aspect of hydroponic setups, you’ll soon see why it’s so important!

Hydroponic Ventilation System

How does hydroponic ventilation systems help?

Hydroponic ventilation systems help by:

  • Maintaining optimal CO2 levels
  • Regulating heat
  • Stabilizing humidity
  • Reducing pests and diseases 
  • Creating stronger plant stems

Let’s talk more in depth about each of these advantages!

Maintains Optimal CO2 Levels

Plants require carbon dioxide in order to photosynthesize- aka, to live and grow! If there’s no injection of CO2, plants in a confined area can easily run low on CO2 as they use it up. 

Hydroponic extraction fans are absolutely necessary to keep CO2 levels high. 

Heat Regulation

Grow lights give off heat, some more than others. For example, HIDs are sure to create a warmer environment than LEDs or fluorescents.

Therefore- especially if you’re using grow lights that emit a lot of excess heat- ventilation can help mitigate the excessive temperature.

Some plants are very particular about the temperatures they can withstand, and ventilation can be a great solution for cool-weather crops that still need bright lighting.

Humidity Stability

Although you may not realize it, the plants in your hydroponic system increase the humidity level in your grow room by sweating out water vapor. 

While some tropical plants thrive under humid conditions, other plants can be severely damaged by high humidity. Increased humidity can also lead to fungal diseases and more.

Ventilation will keep your grow tent at an ideal humidity level so your plants have the perfect environment to thrive.

Pest and disease reduction

Pests and diseases love humid, stagnant air. Some pests or diseases you might run into without ventilation include:

  • Fungus gnats
  • Spider mites
  • Powdery mildew
  • Mold
  • And more

Part of the reason that your chance of pests increases in stagnant grow rooms is because pests like to lay eggs in damp topsoil. A consistent breeze can dry out the top of your soil and make it less appealing to pests.

Stronger plant stems

Stems are naturally strengthened by the breeze outdoors. By fighting against the wind to stay upright, their cell walls become more fortified.

Plants that are never exposed to any ventilation may end up with weak stems that aren’t able to hold the weight of their fruits.

When To Install A Ventilation System?

You should install a ventilation system in your hydroponic grow tent as soon as possible! Ventilation may not be discussed as much as lighting or fertilizer, but that doesn’t mean it’s not important.

Even if you want to dial other factors in first, ventilation should surely be on your to-do list.

Passive Vs. Active Intake System

Passive and active intake systems are two different methods of ventilating your grow room.

Passive intake utilizes negative pressure. Passive intake systems use a fan to blow air out, with no intake fan blowing air in.

Rather, there’s an “intake hole” that lets new air passively enter. The air will naturally enter because of the negative pressure in your grow room.

Your intake hole needs to be about three to four times bigger than your exhaust hole, and you can feel free to have more than one intake hole.

On the other hand- as you may imagine- active intake systems use an intake fan to blow air into your grow tent. That means one fan to blow in and one fan to blow out.

How to choose a fan for a basic ventilation system?

If you’re just starting out, a basic in-line duct fan will do just fine. You’ll want to calculate the CFM rating of your grow room (more on that to come!) in order to know what fan to get.

Once you’ve calculated the CFM, choose a grow fan that has a higher CFM rating than your calculation and you’ll be set to go!

What is the ideal fan size?

Exhaust fans usually come in 4, 6, and 8 inch models.

The larger your grow tent is, the larger model you will need. Surprise! Extensive systems will definitely need an 8 inch model.

When choosing the size for a smaller setup, match it up with your duct size. Six inches is the standard. 

Calculating Fan Strength

Fan strength is measure in CFM- cubic feet per minute.

In order to determine what CFM you need, you’ll need to consider your grow room dimensions along with the exhaust efficiency.

What gets tricky is that there is no set number for exhaust efficiency. If your duct path is long, multiply it by three. If your path is short, multiply it by 2.

Therefore, the formula is as follows:

  • CFM = volume x efficiency drop

Ducting system?

Most home gardeners use flexible aluminum ducting systems. You can also opt for more expensive ducts, but aluminum will do the trick for the majority of hobbyists.

The length and size of your ducts affects your exhaust efficiency (you may remember that term from the last section!).

The shorter the ducting, the better. Likewise, minimize bends. Both of these tips will help increase your exhaust efficiency.

Controlling odors in your grow room

Another pro of ventilation is that is controls odors in your grow room. Sometimes fertilizer smells! And stagnant air is just generally unpleasant.

Proper ventilation will keep odors in your grow room to a minimum.

What is exhaust efficiency, and how is it important?

The exhaust efficiency becomes more and more important, the bigger and more complicated your grow room is. Duct lengths and filter age are two factors- among many- that contribute to exhaust efficiency.

When you’ve decided the CFM of your grow space, buy a fan that has a CFM of an even higher rating. This will ensure that, even if you underestimated during your calculation, you’ll have an adequate CFM.

Ozone Generators

Ozone has the ability to destroy all kinds of microorganisms, ranging from mildew to fungus to mold- and more.

Although it has a bad reputation, ozone is safe for humans in small doses. It’s actually used in hospitals to keep things sanitary!

Ozone generators are becoming more and more affordable and accessible to hydroponic gardeners. They have the power to ward off a plethora of pests and diseases and are certainly worth looking into!

Negative Ion Generators

Ion generators, just like ozone generators, are a preventative measure to protect your crops from harmful pathogens and microorganisms.

Ion generators produce charged ions that are distributed throughout your ventilation system. Essentially, they’re an air purification system.

Activated Carbon Filters

There are some plants whose smell you might want to contain to just your grow room. This is where activated carbon air filters come into play!

Carbon filters pull odors from the air and neutralize them before they go any further. 


Do you need an air filter in hydroponics?

You don’t technically need an air filter in hydroponics, but air filters are certainly worth investing in. One kind of hydroponic air filter is an activated carbon filter. It’s very good at keeping odors in your grow room. I’m sure we can all think of a plant whose smell you may want to contain!

Does a sealed grow room need fresh air?

Sealed grow rooms need fresh air via ventilation. Ventilation encourages stronger stems by mimicking outdoor breeze. It also increases CO2 levels so your plants can successfully photosynthesize.

How much airflow does a grow room need?

A grow room needs all of its air to be recycled every 1-3 minutes. This means you need a constant flow of air for proper ventilation.

Where should a grow room fan be placed?

Your extraction fan should be placed as high as possible in your grow room. This will suck out all the heat that’s risen and keep temperatures at a reasonable level.

Do plants need ventilation at night?

Plants need ventilation at night just like they do during the day. Think about it- the wind doesn’t stop blowing at night outside! All of the benefits of ventilation are just as important at night as they are during the day.

Do plants need air at night?

Plants need air at night. Plants need air to survive and would die without it. Even though plants aren’t photosynthesizing at night, they intake carbon dioxide and breathe out oxygen through their stomata.

How do you make a homemade carbon filter?

Making a homemade carbon filter is a bit of an extensive process. You need to replicate the pre-filter, the body, and of course, add the carbon. At the end of the day you’ll have a higher-quality filter if you buy one, and it will save you a lot of effort.

Do carbon filters actually work?

Carbon filters actually work. The bad odor molecules attach themselves to the carbon molecules and get trapped within the filter.


Whew! There’s a lot more to hydroponic ventilation than meets the eye. It only makes sense that you wouldn’t want your grow room to be stuffy or stagnant! All of the benefits of ventilation become painfully obvious once you read about them. Hopefully this article will give you the push you need to install a hydroponic ventilation system ASAP.

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