How to Keep Grow Tent Walls From Sucking In

Bracing Frame to keep grow tent walls from sucking in

Help! My tent walls are sucking in!

We have a simple solution for this common problem!

Build a Bracing Frame and increase the effective size of your tent!

It is important to maintain negative air pressure inside your grow space. This is accomplished by running an exhaust fan that is more powerful than the intake fan (or passive intake). Setting up your exhaust like this promotes airflow which is critical to manage heat and humidity. This set-up also allows you to control odor by connecting a carbon filter to your exhaust fan.

The Problem

If you grow inside a tent, the negative air pressure makes the walls of the tent pull in. This decreases the effective growing area inside your tent and can squeeze your plants.

The Solution

Build a PVC bracing frame and hang it from the top of your tent!


Buy your PVC tubing and connectors locally, they are not a good bargain online.

  • 1/2” PVC: This is best because it is rigid and light weight. You should get enough linear feet to go completely around your tent. For a 4’x4’ tent you will need 16’ of PVC.
  • 90* connectors: You will need four 90 degree connectors. Get the slip connectors. They fit snuggly. You do not need any adhesive for this application.
  • PVC pipe cutter: If you don’t already have a PVC pipe cutter then this is not the only reason to get one. Obviously it will come in handy to cut the PVC during this project, but PVC pipe cutters are also great at cutting bamboo (used for plant supports) and for cutting down the plant at harvest time. This is a decent pipe cutter and a good price.
  • Rope, twine, or ratchet pulleys: I have a few extra ratchet pulleys that I bought for my lights and I use them to attach the frame to the top bars in the tent. As a cheaper alternative you could use rope or twine.

The Process

You want to cut the frame to be as wide as the interior of the tent. I have a four-foot by four-foot tent, and you might think that the interior measurement is 48 inches, but it is only 45”. However, my frame is 46” wide. It actually pushes the tent apart by an extra inch.

To determine the exact size for your frame you will have to do a little trial and error. Make your initial cuts slightly large and then cut down to size if needed. PVC is great because you can easily trim it down to size.

My frame does not come all the way to the front of my tent, because I do not use the front section for my plants. As a result, I have to tie the frame to the back vertical supports. If I didn’t secure the frame to the back wall, the negative air pressure would pull the back wall in and push the frame forward. Since the frame spans side to side, the pressure on the two walls equalize and the frame does not move side to side.

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Author: Dr Coco

I am a university professor and have taught courses in horticulture. I am coco for cannabis and I hope you are coco for cannabis too :) Grower Love!