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Grow Tent Ventilation

grow tent ventilation

When growing cannabis indoors, you will definitely require some grow tent ventilation or a way to ventilate your grow room.

Why is grow room ventilation important for growing cannabis?

Fresh air is essential for cannabis plants for two primary reasons:

  • Photosynthesis

Photosynthesis, the process by which plants convert light, water, and carbon dioxide in the atmosphere into food, is fueled by oxygen in the air.

  • Breathability

Plants breathe in and expel oxygen to convert glucose and oxygen from photosynthesis into energy for development.

If you don’t provide your cannabis plants with enough fresh air, they will die. Pathogens and pests will thrive in a shortage of fresh air in your grow room before this occurs. A lack of sufficient ventilation creates a hot, humid climate where many pests and diseases thrive, making your plants vulnerable to infection.

Understanding grow tent ventilation

Many new cannabis producers are baffled or overwhelmed when it comes to ventilation. The fundamental concepts of ventilation in your grow room are simple: remove old, humid air from the chamber and replace it with new, cold air from the outside.’

Cannabis grow tent
Everything you need in a grow tent.

In case you’re still scratching your head, here’s an explanation for why the air in your tent/room becomes so hot and muggy. Let’s take a closer look at it:

  • Transpiration

Cannabis plants naturally expel water (or sweat). This movement of water and nutrients from the earth to the plant’s branches, leaves, and flowers is crucial. The stomata and cuticles on the leaves of cannabis plants and the lenticels (pores present in exterior plant tissue such as stems) generate a pull that pulls water from the roots to the rest of the plant. Your plants naturally expel water into the atmosphere, which raises the relative humidity in your grow area.

  • Heat Emitted by Grow Lamps

To cultivate plants, you need a light source that produces heat. With that being the case, many gardeners still choose to use metal halide or high-pressure sodium (or both) HIDs over LEDs since they generate higher yields. Your grow lights will automatically raise the ideal temperature and humidity in your grow tent/room if they are not adequately ventilated.

What do you need for grow room ventilation setup?

Here’s a list of all the things you’ll need to keep your grow area adequately ventilated.

Extractor Fan

Extractor fans remove stale air from the growing environment. It would help to place your extractor at the top of your room/tent since hot air naturally rises. In some instances, grow lights or reflectors come with an exhaust adapter.

Carbon Filter

The purpose of carbon filters is to remove airborne pollutants. You can remove the terpenes produced by your plants from the air by attaching them to your exhaust system. In cannabis grow rooms, activated carbon filters in grow rooms are an excellent solution.

Oscillating fans

The last component of the ventilation jigsaw is the oscillating fan. A few carefully positioned fans in your grow room will help you get the most out of your space.

Indoor grow tent
Indoor grow tent with multiple fans

It will not only reinforce the branches of your crops. Still, it will also prevent stagnant air from building up around your area, lowering the possibility of pests or diseases damaging your harvest.

Different grow space carbon filter setups 

As one would guess from the name, a variety of extraction and carbon filter systems are available to keep plants healthy and odors to a minimum. Let’s weigh the advantages and disadvantages of the various possibilities.

Carbon Filter to Extractor to Exhaust

Exhaust systems, fans, and filters have often been installed in this manner in a grow tent.

Carbon Filter Extractor Exhaust

At the start of your exhaust system, the carbon filter removes pollutants before the air is blasted through your vents and outdoors.


  • Airborne pollutants are screened out before they reach your fan, reducing harm.


  • Because of its size, it may not be suitable for smaller tents or rooms.

Carbon Filter > Lights > Extractor > Exhaust hood

 This is for farmers who use lights with an enclosed ventilation system. Filter before your grow lights and exhaust fans once your lights are installed.


  • The exhaust setup is simple and small, thanks to its design.


  • Only works with grow lights that have a sealed venting system

Carbon Filter > Exhaust > Extractor

It is not uncommon for growers to choose to install their filters directly at the end of their exhaust system. In this manner, the air in their room/tent gets sanitized just before it’s blasted out the door.


  • For growers with restricted room, the carbon filter may be positioned outside of the grow room/tent if required.


  • It may cause harm to the fan by drawing in dirty air.

Should an extractor fan be inside or outside a grow tent?

Newbie growers often ask themselves these questions. In general, we suggest that you place your exhaust fan and all of its components inside your grow tent to reduce noise emissions. However, if you’re short on the room or struggle to keep your tent cool, you may place your fan outside. Your extractor’s exhaust system must be airtight, regardless of where you put it.

How to ventilate a micro cannabis grow

Micro-growers may keep ventilation simple by growing one or two plants in a cupboard or closet. A micro-grow may be ventilated for almost nothing. Using oscillating fans and opening windows near your tent a few times a day may be enough to ventilate your grow adequately. There should be no concerns with heat for growers utilizing LED, CFL or low-power HID systems (250W or less). Using a dehumidifier to combat humidity in a micro-grow is as easy as plugging it in.

Ventilating a greenhouse

There should be several vents that may be opened and closed as needed by greenhouse producers. Ventilation flaps may be manually opened and closed in most simple greenhouses coated with plastic. In the worst-case scenario, you may be able to eliminate a windowpane from a glass greenhouse or unlock the doors slightly.

It’s all about letting the air in. With so many cannabis plants transpiring, a greenhouse may get quite humid. As plants age, they will emit more water vapor and raise the relative humidity in the area. It is true both inside and outdoors. Every growing area must have enough ventilation. It is common for greenhouse gardeners with large blooms to open all vents and even make their own to prevent the spread of bud rot.

Discreet and efficient grow tent ventilation

You can improve ventilation by installing wicker curtains in front of the window where you’ll be opening and closing it. It will shield the grow chamber from view while allowing fresh air to pass through. After that, you may begin assembling your ductwork. You can run the ducting via a cut-out hole in a piece of plasterboard or plywood that has been drilled into the window frame. Start by making the opening smaller, then fill it in.

Managing airflow is important

There is no need to worry about airflow management in your cannabis grow area. Plants will thrive if you follow the advice in this tutorial and make sure that the air in your tent or room is continually replaced.

Picture of Taylor Christianson

Taylor Christianson

Taylor is an indoor expert. Through their writing, they offer a masterclass on growing cannabis indoors, maintaining a productive growing environment, and guiding growers through all the stages of growth both indoors and outdoors. Combining multiple fields of expertise allows for Taylor to give in-depth insights into overall cannabis growing. About this Author

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