How Often Should I Run Exhaust Fan In a Grow Tent?

10 November 2019

Have you just bought a grow tent? Well, you have made a very economical and beneficial decision! Whether it is for your passion or the growth of your business.

Grow tents are almost the perfect antidote for the problems caused by indoor plantations; like other technologies, you can use them to fabricate outstanding indoor plant growth.

However, if not used properly, it has the potential to cause havoc in your indoor plantation.

The information in this article addresses the most frequently asked questions modern urban farmers would ask. It throws light at almost all parts of the ventilation system in a grow tent and further explains why an ideal running time of exhaust is essential for any grow tent.

Ideal Running Time For An Exhaust Fan

We must first measure the grow tent to know the ideal running time for an exhaust fans inside a grow tent. Different grow tents require different amounts of ventilation.

You can carry out the analysis of a grow tent in cubic feet. After we have taken the proper measurement of the room, we need to divide it by three to get the ideal exhaust fan running time inside a to-grow tent.


The unit for running an exhaust fan is CFM. This stands for cubic feet per minute. This lets us know how much air should be exchanged in the specific grow tent we are measuring.

CFM depends on two things. Firstly, it depends on the size of the grow tent and secondly on the size of the exhaust. The influence of the exhaust fan size is so less that it is usually neglected.

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Mathematical explanation:

In almost every grow tent, an exhaust should refresh the air inside after every three minutes. To optimize the exhaust according to the ideal exhaust time, we have to divide the total volume of our grow tent by three.


Suppose you possess a grow tent about 720 cubic feet in size.

If that is the case, you must divide 720 by three. By doing this, you get your CFM, which is the unit of the ideal time for running an exhaust. In this case, the CFM that is calculated equals 240.

720 / 3 = 240 CFM


This is the ideal time for how much an exhaust fan should run inside a grow tent of a specific volume. However, it is always advised to use an exhaust with more CFM.

This is mainly because inside a grow tent, many other factors begin to play a role, which I have discussed below. These factors affect ventilation in a grow tent.

Therefore, an exhaust with slightly higher CFM is preferred as it helps maintain the perfect ventilation your plants are dying for.


Grow tents are 21st-century greenhouses. They serve as the perfect solution for people who find greenhouses not economical enough. These box-shaped canvas enclosure can give plants their ideal conditions for growth.

Like all living things, plants also need a specific environment for perfect growth. Therefore, we must use grow tents properly. It is almost crucial for the healthy growth of your plants.

In horticulture, proper ventilation is as essential for plants as breathing is for humans. It refers to the exchange of stale air inside the grow tent with fresh air.

If a tent is not adequately ventilated, it will result in either of the two conditions:

Therefore, ventilation is the key to having a perfect grow tent. Learn how to set up grow tent ventilation properly.

Why is proper ventilation necessary?

There are three fundamental reasons why without ventilation, plants experience slow or stunted growth. They are as follows:


It would help if you controlled humidity in indoor plantations. All professional urban farmers know how rain can affect plant growth. The optimum humidity level for healthy plant growth is about 45% to 75%.

If the humidity in your plants is about 20 to 40 percent, It must be taken control of. Otherwise, you are at significant risk of losing your plants. Ventilation can come to your rescue if you are stuck in this situation.


Picture photosynthesis as the kitchen of plants, and the stock for that kitchen is Carbon Dioxide. New carbon dioxide can only come from proper ventilation.

Without adequate ventilation, the amount of carbon dioxide inside a grow tent would become stale, and therefore, it will become destructive instead of constructive for the plants.


In every grow tent, light is needed to grow the plants correctly. It takes up the role of sunlight (heat production) and helps to increase the temperature inside the grow tent.

This increase in temperature inside a grow tent must be taken care of. Every plant has its optimum temperature. Proper ventilation helps provide plants with the ideal temperature for healthy growth. If your grow tent becomes too hot, try this ventilation method.

Additional Information


Exhausts are the most critical component in any ventilation system. It helps remove heat, bringing fresh doses of CO2 and maintaining the humidity inside the ventilation system.

It must be installed high up in the tent. Since hot air rises while the cold air being denser, settles down. We need to remove the heat from grow tents. Therefore, exhausts are permanently installed at the top.

Fresh air intake:

The second most important piece of equipment is the sharp air intake. Make sure it is connected precisely to the opposite side of the exhaust. This will help untangle the wires, which may overlap while installing the ventilation. The blocking of air due to overlapping hoses causes severe troublesome obstruction.

Amount of plants:

Make sure not to overcrowd the plants inside the grow tent. These acts cause the plants to not develop to their full extent, injuring their growth. If you want healthy and maximum plant growth, ensure you do not overcrowd the grow tent.


Urban farmers must be familiar with the idea of minimalism. The secret to genius in the indoor plantation is simplicity, not complexity. Therefore, instead of focusing on the number of plants you grow inside a grow tent, you should focus on the quality of plants you produce.

Try to be a master of building one kind of plant instead of being a jack at increasing all types of them.

Grow Room ACs:

Most people are not familiar with a modern ventilation system for grow tents. The popular modern way of ventilation is now the use of Air Conditioners. Apart from being slightly uneconomical, they give urban farmers reasonable ventilation system control. You can use them in a wide range of climates.

And also, you can place it anywhere inside the grow tent. However, it can cause damage to plants if set too close to them.

Why is this important?

The ventilation system is a critical part of grow tent, it is as essential to your plants as air is to you. The information we have shared with you is the nectar of three years of experience of people who have adopted indoor plantation as their profession.

A pro tip is consistently checking your ventilation system and reporting any problem to an electrician. You must also have basic knowledge of other necessary parts such as air humidifiers, and grow lights.

Bottom Line

Ventilation systems are the most fundamental necessity for letting plants thrive. Most people generally focus on what plants to grow instead of concentrating on how to improve their growth.

Urban farmers must learn about the ideal conditions for the growth of their plants. If you are reading this, you are probably on the right way to urban farming. Therefore, kudos for your effort, and happy farming!

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