Exhaust Setup for an 8 x 8 Grow Room Tent

by Kerry

I have an 8 x 8 grow room tent that I'm not sure how to setup the ventilation for (the exhaust and intake). Could you please draw a diagram how it should be setup. Thank you for your help!

Answer: Kerry- enclosed garden spaces such as closets, grow boxes, and grow tents quickly build up too much heat. Heat rises, so the number one rule would be to exhaust the grow tent from holes near the top. In the picture, you can see a yellow arrow pointing to the exhaust hole in this tent.

As you exhaust air, you create negative air pressure (a vacuum) inside the grow tent. Opening some air intake vents will automatically allow cool, fresh air to pour into the grow tent. Cold air sinks, so these air intake holes should be positioned low to the ground to scoop the coolest air right off of the floor. In the picture, there are red arrows pointing to a few air intake points.


In professional grow tents, there are usually velcro flaps over the air intake holes (like the rectangular flaps in the picture). This allows you to "customize" the airflow pattern inside your grow tent.

You will probably learn that your lights put off too much heat, and ventilating the grow tent with cool air off of the floor just isn't enough to keep your grow tent from over-heating. There are two other things you can do if your garden area is over 75*F. If you ventilate your grow lights with an exhaust fan of their own, this will prevent much of their heat from going into the grow tent. In the picture, you can see an air intake on the side of the tent connected with blue lines to an air exhaust on the other side of the tent.

Air would be taken from the room outside the grow tent, passed through your grow lights, and exhausted back into the room (outside the tent). In this way the air moving through your grow lights would be kept separate from the air moving through your garden area (inside the tent). One thing to keep in mind- it is best to exhaust all of this warm air to the outdoors. If you are simply exhausting it into the room in which you set up your grow tent, the entire room will become too warm to keep your grow tent under 75*.

If the entire room in which you have your tent becomes too warm, you will need to run an exhaust fan for the room (so you might as well exhaust the lights and tent to the outdoors to begin with). Any vents to the outdoors should have their fans running constantly....even at night. As soon as you turn them off, the vent duct will siphon cold outdoor air into your garden (from outdoors) and stunt the growth of your plants.


As long as you set your grow tent up in a room that is kept dark, you do not have to worry about light contamination from the room making it into your grow tent during the flowering stage. It is critical that any dark period remain completely dark and un-interrupted. Finally, I included the other grow tent picture to stress the importance of air circulation INSIDE the grow tent.

Air exhaust is important to reduce temperature, reduce humidity, and bring fresh supplies of CO2 to the plants....but it's the air circulation around the plants (supplied by oscillating fans) that act as their lungs. I hope this answers your question....Happy Growing!

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Nov 17, 2013
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by: Original Green Grow

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Happy to see new people there and answer questions about getting set up for indoor growing.

Cheers, Original Green Grow

PS This blog is a GREAT resource!

Apr 07, 2011
by: Anonymous

If you are running the exaust dirictly through your light( the blue lines), do you still need to run an exaust out of the top? also i have 2 inline duct fans for the exaust, should i use them both on the light ( onr on the right d=side and other on the left with one pushing and other pulling going in same direction) ?? and last do i hook up my inline fans in the duct on the inside of the tent or outside?

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