Why A Fan for Your Grow Room Will Help Grow Your Marijuana Faster

Grow Room Fan

When growing cannabis indoors, installing a fan is one of the first things you will think about. In the wild, cannabis plants have unlimited access to the pleasant breeze of fresh air.

If you’re looking into setting up a fan in your grow room, here is the guide you should look at first.

Do I need a fan for my grow room? Yes. While setting up oscillating fans will help you moderate the temperature and humidity, it might not be enough. Adding an air extractor to your fan system will keep the air in your grow room or tent fresh.

In this article, you will learn different ideas and information regarding your grow room and its ventilation. You must be able to grow your own farm in the comfort of your indoor spaces.

Grow Room 101

Many people have tried growing marijuana indoors and found themselves encountering many problems. They set up a fan, which will provide air circulation for the plants, but this might not be enough for them to grow.

Grow room ventilation requires more than just the fan itself; you need to know the science behind it.

The good news is, the more you fail, the more lessons you learn, and you can use this new knowledge to do what is right for your grow room. Grow room ventilation is not hard if you have the right knowledge and research all the fundamentals.

Why Is Ventilation Needed in a Grow Room?

You might be wondering why many grow rooms and tents need to be ventilated. There are a few reasons for this. Plants that are grown outdoors enjoy different mitigating effects of sunshine, evaporation, light breezes, and precipitation.

But for indoor planting, you tend to substitute fans for breezes and evaporation, adding grow lights for sunshine and watering systems for their precipitation.

The issue here is that people tend to forget that outside, there is a wide array of air circulation that is more natural compared to your grow room.

You need to have at least a fan and some air extraction system to keep the air flowing in your grow room fresh. Here are some possible reasons why ventilation is needed:

Remove Excess Heat

As mentioned, you need a grow light to act like sunshine for your plants, and grow lights emit heat. It might sound minor, but a few degrees in temperature can make a big difference between a successful plant and a less successful one.

You also have to be wary of other grow lights that can emit more heat than others. One thing is for sure: All of these grow lights can produce enough heat to merit a ventilation process.

Control Humidity

Humidity is another factor that you should consider because it can contribute to your indoor growing systems’ problems.

Throughout the day, plants can emit water vapor that can increase the humidity of your grow room. If you don’t control the humidity, the chances are that it will lead to poor growing conditions resulting in pests and diseases.

A good ventilation system can remove some of the water released during transpiration. It will allow your plants to absorb more water and pull up nutrients through their root systems.

Prevent Pests and Diseases

Pests and disease build-up will follow humidity, so air circulation is essential. This can help prevent these buildups because most molds and other fungus prefer stagnant and humid conditions.

Some pests even lay their eggs in damp topsoil, so a fan’s presence will keep the soil’s surface layer dry and slow down the reproductive cycle.

Control CO2

The science of botany is easy to understand, as plants need an outside air force to get their CO2. Plants must absorb CO2 throughout the day as a part of their nutrient cycle.

If you have a grow room or a sealed tent, it could mean that the level of CO2 will gradually decrease. Proper ventilation will bring fresh air and fresh CO2 from the outside and remove the old air from your grow room.

Manage Wind Stress

Most of your outdoor plants are constantly buffeted by the wind, which makes their stems stronger. This is necessary so that they can become strong enough to hold and bear fruit.

Stronger plants grow and produce better than weaker plants. Good ventilation systems can prevent a lot of diseases from developing. It can also help protect your plants from pests like spider mites and fungus.

How to Ventilate Your Grow Room

A ventilation system requires a lot of work and research, so you might need to take some time before rushing to make one for yourself. Luckily, you can read the pointers below so that you can start ventilating your own grow room.

Place Oscillating Fans in the Grow Room

As you learn how to vent your own grow room, keep in mind that your grow room should have two types of fans: air extraction fans and oscillating fans.

The first one that you should be aware of is the oscillating fans, which are both cheap and effective. They are the ones responsible for blowing air continuously above, under, or around your plants.

As a result, they help to keep the grow room cool and improve air circulation.

Oscillating fans might be good for your grow room, as they can moderate the temperature and humidity. But this is not enough, as you need to add an air extractor fan that will keep the air in your growing room fresh.

Air Extractor Fan System

Using an air extractor fan system can help in the cycle of getting the old air out and bringing in the fresh air. It is imperative because it will help the plant survive and grow with the proper nutrients.

Your air extractor fan system will replace the air in your grow room every minute or at least every three to five minutes. So, you might need to consider the right side of the fan for this job.

Combining a grow tent setup with grow tent ventilation is probably one of the best decisions you can make. Just be mindful of taking a minute to read about grow tent ventilation and the best time to install it.

Calculating Fan Strength

It will be quite challenging, but you can still achieve good results by following this part. The reason is that circulating fan strength might require a little math, though it is relatively simple and basic.

Fans are known to be rated by CFM or cubic feet per minute. To figure it out, you have to know the dimensions of your grow room or tent and the exhaust efficiency.

Calculate the volume of your grow room by multiplying the length, width, and height. This will be the cubic feet measurement of your room.

Save this for later, as you will need to work on the efficiency drop. The efficiency varies based on the age, brand of filter, and duct length between the fan and the filter.

At a minimum, you want to multiply the volume of your room by 25%. If your duct path is long, multiply it by 3, while if you have a short path, multiply it by 2.

Passive Intake vs. Active Intake

There are two ways to bring your air into your grow room: passive intake and active intake. Passive intake is known to rely on passive airflow and negative pressure.

You have a fan blowing out air with grow room ventilation, but no fan blowing in the air. As a result, you have an intake hole that passively allows new air to enter.

To make the passive system work, you must have three or four holes other than your exhaust hole. This will prevent your fan from overworking and keep your ventilation system running efficiently, providing enough suction.

Active intake systems can draw air into your grow room using a fan, which means that you have one fan blowing in air and another one blowing out air. The size of the intake hole should not matter as much in this particular system.


Grow room ventilation systems are a crucial part of indoor growing, as they can make or break your results. Choosing the most suitable ventilation system for your grow room can be a little difficult.

That is why it is essential to know and understand how ventilation systems work. There are also benefits to grow room ventilation that you do not want to miss. Once you have learned the basics, your farm will be in a better position.

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